fix(docker): trust bind-mounted repos via git safe.directory

The container runs as root over uid-1000-owned host repos; git's dubious-
ownership guard made every project read as not-a-repo, hiding the git diff
panel's Git tab and nulling the branch indicator. Bakes safe.directory='*'
into the runtime image. Applied live to the running container too.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.codecontextignore

@@ -21,6 +21,7 @@ out/
 .opencode/
 .vscode/
 .idea/
+.claude/worktrees/
 
 # Test artifacts / coverage
 coverage/

.env.example

@@ -11,6 +11,15 @@ POSTGRES_PASSWORD=CHANGE_ME
 # point BooCode at a different SearXNG instance.
 SEARXNG_URL=http://100.114.205.53:8888
 
+# Context7 MCP key. Referenced from data/mcp.json as "{env:CONTEXT7_API_KEY}"
+# ({env:VAR} substitution, opencode-compatible). Leave unset to send no key.
+# CONTEXT7_API_KEY=ctx7sk-...
+
+# Task model: lightweight model for auto-naming, search rewrite, etc.
+# Direct llama-server instance (NOT llama-swap). Falls back to LLAMA_SWAP_URL
+# with FAST_MODEL when unset.
+# TASK_MODEL_URL=http://100.90.172.55:7995
+
 # v1.13.15-tools: BOOCODE_TOOLS narrows the tool whitelist sent to the LLM.
 # Unset (default) → all tools (~21k schema). Useful primarily for single-purpose
 # sessions where the model only needs read-only filesystem access.

.gitignore

@@ -15,4 +15,6 @@ secrets/
 data/*
 !data/AGENTS.md
 !data/skills/
-!data/mcp.json
+!data/mcp.example.json
+!data/coder-providers.example.json
+codecontext/fork.tar.gz

AGENTS.md

@@ -1,109 +0,0 @@
-# Agent navigation
-
-Cursor/agent entry point for the BooCode monorepo. **Deep engineering reference:** `CLAUDE.md` (Claude Code). This file is navigation + task routing only.
-
-Last updated: 2026-05-25
-
-## Doc map
-
-| Need | Read |
-|------|------|
-| Commands, gotchas, inference, DB, env | `CLAUDE.md` |
-| Read-only chat behavior | `BOOCHAT.md` |
-| Write tools, dispatch, pending changes | `BOOCODER.md` |
-| Shipped vs planned, version order | `boocode_roadmap.md` |
-| Latest release truth | `CHANGELOG.md` (top entry = current) |
-| System diagram + data flow | `docs/ARCHITECTURE.md` |
-| Current focus / blockers | `CURRENT.md` |
-| Batch convention | `openspec/README.md` |
-| Shipped batch snapshots | `openspec/changes/archived/` |
-| Chat agent personas + tool lists | `data/AGENTS.md` |
-| External repo lift inventory | `boocode_code_review.md` |
-
-## Monorepo layout (actual)
-
-Three **surfaces**, four **packages**. There is no `apps/chat/` directory.
-
-| Surface | Packages | Port | Deploy |
-|---------|----------|------|--------|
-| **BooChat** | `apps/server` (API + inference) + `apps/web` (SPA) | `100.114.205.53:9500` | Docker `boocode` container |
-| **BooTerm** | `apps/booterm` | `100.114.205.53:9501` | Docker `booterm` container |
-| **BooCoder** | `apps/coder` | host `:9502` | systemd `boocoder.service` (not Docker since v2.1.0) |
-
-Shared: Postgres 16 — Docker service `boocode_db`, **database name `boochat`**, host port `127.0.0.1:5500`.
-
-## Task routing
-
-| Task type | Start here |
-|-----------|------------|
-| Chat inference / tools / compaction | `apps/server/src/services/inference/` |
-| WS frames | `apps/server/src/types/ws-frames.ts` + `apps/web/src/api/ws-frames.ts` (keep in sync) |
-| Frontend chat UI | `apps/web/src/components/`, hooks in `apps/web/src/hooks/` |
-| BooCoder write tools / dispatch | `apps/coder/src/` — build server first (`pnpm -C apps/server build`) |
-| Provider picker / external agents | `apps/coder/src/services/provider-registry.ts`, `dispatcher.ts`, `agent-probe.ts` |
-| Terminal panes | `apps/booterm/src/`, frontend `TerminalPane.tsx` |
-| Schema changes | `apps/server/src/schema.sql` + sync `*_STATUSES` in `apps/server/src/types/api.ts` |
-| New batch / feature | `openspec/changes/<slug>/proposal.md` + `tasks.md` (see below) |
-
-## Verification (before claiming done)
-
-```bash
-pnpm -C apps/server test && pnpm -C apps/server build
-npx tsc -p apps/web/tsconfig.app.json --noEmit   # root tsc can miss web errors
-curl http://100.114.205.53:9500/api/health       # Tailscale IP, not localhost:9500
-curl http://100.114.205.53:9502/api/health       # BooCoder on host
-```
-
-Deploy truth beats source-only reads — check running health + `git log --oneline -3`.
-
-## Hard rules (from CLAUDE.md)
-
-- **Do not commit or push** unless Sam explicitly asks.
-- **No app-layer auth** — Authelia at the reverse proxy.
-- **Parts table is source of truth** — read message tool fields from `messages_with_parts` view, write via `insertParts`.
-- **New WS frame type** — update server + web schemas; publish via `publishFrame` / `publishUserFrame` only.
-- **New tool** — own file in `services/`, register in `tools.ts` `ALL_TOOLS`; whitelists derive from there, never hardcoded.
-- **Typecheck web with per-app tsconfig** — root `tsc --noEmit` uses project references and can miss errors.
-- **`includeUsage: true`** on `createOpenAICompatible` in `provider.ts` — do not remove.
-- **Agent dispatch** — direct `spawn`/`exec` on host via `install_path` (v2.1.0+); SSH helpers deprecated.
-- **Event dedup** — server publishes via broker; frontend must not duplicate `sessionEvents.emit` after API calls that already WS-broadcast.
-
-## Using openspec with Cursor
-
-Openspec is a **folder convention**, not a CLI. Use it to give agents a scoped brief before coding.
-
-### When starting a batch
-
-1. Create `openspec/changes/<slug>/` (lowercase-hyphenated, e.g. `v2-2-arena-ui`).
-2. Write `proposal.md` — why, scope, non-goals, dependencies.
-3. Write `tasks.md` — numbered checkbox steps (build + smoke).
-4. Optional `design.md` — schema/API decisions that outlive the batch.
-
-See `openspec/README.md` for the full shape. Shipped pre-v1.13.15 batches live in `openspec/changes/archived/` as snapshots only.
-
-### Prompting an agent
-
-```
-@openspec/changes/<slug>/proposal.md @openspec/changes/<slug>/tasks.md
-Implement tasks 1–3. Server tests must pass. Do not commit.
-```
-
-Attach the spec files with `@` so they load into context. Point at specific code paths when known:
-
-```
-@openspec/changes/v2-x/proposal.md
-Extend apps/coder/src/routes/providers.ts — follow provider-registry.ts patterns.
-```
-
-### After shipping
-
-- Tag: `vMAJOR.MINOR.PATCH-slug`
-- Add entry to top of `CHANGELOG.md`
-- Move or snapshot the openspec folder to `archived/` if you want history preserved
-- Update `CURRENT.md` and `boocode_roadmap.md` shipped table if the batch was roadmap-tracked
-
-### What not to use openspec for
-
-- One-line bug fixes — just describe the bug + file.
-- Exploratory questions — Ask mode + `@CLAUDE.md` is enough.
-- Duplicating `CLAUDE.md` — openspec is per-batch scope, not permanent conventions.

BOOCHAT.md

@@ -28,6 +28,11 @@
 - Prefer codecontext (`search_symbols`, `get_symbol_info`, `get_dependencies`) over `grep` for symbol-level questions. Fall back to `grep` / `view_file` when codecontext returns degraded or empty results — that signals an unsupported language or parse failure.
 - Verify before reporting work complete: run the relevant test/build/smoke command and confirm output matches the claim. Evidence first, assertion second.
 
+## Recovery and context (v2.7)
+
+- **Heed the recovery nudge.** Native inference tracks consecutive tool **failures** (`mistake-tracker.ts`): after 3 in a row with no successful step between, a `mistake_recovery` sentinel is injected telling you to re-read tool schemas, verify a path exists before acting, and try a *different* approach — not retry variations of the same failing call. Ignoring it (a second failure run with the nudge still outstanding) **escalates and stops the turn** to protect the step budget. This complements the doom-loop guard, which only catches *identical* repeats.
+- **Files-read provenance survives compaction.** Paths you read via `view_file` / `grep` / `find_files` / `list_dir` are accumulated and merged into a cumulative `## Files Read` ledger in the rolling summary, so a file read long ago stays in context across compactions. You don't manage this — but it means you usually don't need to re-read a file just because the raw turn scrolled out of the window.
+
 ## Output format
 
 - Stay in Markdown by default for every reply, short or long.

BOOCODER.md

@@ -23,6 +23,8 @@ You are BooCoder, a write-capable coding agent. You can read AND modify files wi
 
 Every file modification queues in `pending_changes` before touching disk. The user sees a diff preview and approves/rejects each change. Never bypass this queue — it is the safety boundary between inference and the filesystem.
 
+`edit_file`'s `old_string` match is **fuzzy** (`fuzzy-match.ts`, v2.7.1): an exact → per-line-whitespace → unicode-canonicalization (curly quotes/dashes/nbsp) → Levenshtein-≥0.66 ladder, so minor whitespace/indentation/unicode drift in `old_string` still lands on the right span. Two consequences: a near-miss `old_string` may still apply (verify the queued diff is what you intended), and an `old_string` matching **more than one** place is rejected as **ambiguous** rather than editing the first — add surrounding context to disambiguate. A genuine non-match returns a clear failure, not a thrown error.
+
 ## Behavior
 
 - Show diffs clearly. Explain what you're changing and why.
@@ -37,3 +39,113 @@ Every file modification queues in `pending_changes` before touching disk. The us
 - Never count `dist/` directory sizes as source lines. Only count `src/**/*.ts` files. Compiled output is inflated by inlined types and transpilation artifacts.
 - Before claiming a feature works, run the actual command and show the output. "Should work" is not verification. Acceptable evidence: test output (`pnpm test`), build output (`pnpm build`), curl response, docker logs, `\d tablename` output. If you can't run it, say so explicitly — don't assert success without evidence.
 - When reporting counts (tools, tests, files, routes, lines), derive the number from a command (`grep -c`, `wc -l`, test runner output) — not from memory or approximation.
+
+## Provider lifecycle (v2.3)
+
+BooCoder's coding agents are a **config-backed registry**: built-ins live in `provider-registry.ts`, and `data/coder-providers.json` layers overrides + custom entries on top. Registration ≠ installation — the config lists what you *want*; a probe reports what's *ready*.
+
+### Config file: `data/coder-providers.json`
+
+Resolved from `CODER_PROVIDERS_PATH` (default `/data/coder-providers.json`; dev/host path `/opt/boocode/data/coder-providers.json`). It is **gitignored** — it's live runtime config that the coder reads *and writes* (UI toggles `PATCH` it), so tracking it would churn `git status`. The tracked reference is `data/coder-providers.example.json`; copy it to `coder-providers.json` to seed overrides. A missing file, invalid JSON, or a schema mismatch all fall back to built-ins-only — loading never throws at startup.
+
+```json
+{
+  "providers": {
+    "goose": { "enabled": false },
+    "amp-acp": {
+      "extends": "acp",
+      "label": "Amp",
+      "description": "ACP wrapper for Amp",
+      "command": ["amp-acp"],
+      "enabled": true
+    }
+  }
+}
+```
+
+Per-provider override fields (all optional):
+
+| Field | Meaning |
+|-------|---------|
+| `extends` | `"acp"` — required for a NEW (custom) provider; built-in overrides omit it |
+| `label` | Display name (required for custom) |
+| `description` | Sub-label shown in the picker / settings |
+| `command` | `[binary, ...args]` to spawn (required for custom; overrides a built-in's default argv) |
+| `env` | Extra env vars merged into the spawn |
+| `enabled` | Default `true`; `false` hides it from the composer |
+| `order` | UI sort key |
+| `models` / `additionalModels` | Replace / merge onto the discovered model list |
+
+A PATCH to one provider id **replaces that id's override object wholesale** (per-id shallow merge), so to flip a single field keep the rest; a `null` value for an id deletes its override (reverts to the built-in default).
+
+### Refresh contract
+
+The snapshot is cached and a provider's cold ACP probe (tier-2) is **skipped** while `available_agents.last_probed_at` is younger than `PROVIDER_PROBE_TTL_MS` (default `86400000` = 24h). Opening the composer is therefore fast and does not re-probe. To force a cold re-probe (after installing a CLI or editing models): **`POST /api/providers/refresh`** (the Refresh button in the Providers settings tab), which clears the cache and re-probes.
+
+### Enable / disable
+
+Two ways:
+- **Settings → Providers tab** — open the sidebar → **Settings** → **Providers**: toggle a provider on/off, refresh it, or open its diagnostic. (Earlier builds exposed a gear in the composer; that control was moved into Settings.)
+- **Edit the config** (`"enabled": false`) then `POST /api/providers/refresh`.
+
+A **disabled** provider leaves the composer's provider picker but stays listed in the Providers tab (status "Disabled") so you can re-enable it. **Native `boocode` is always-on** — an `enabled:false` on it is ignored (with a warn log) and it is never rendered as toggleable.
+
+### Adding a custom ACP provider
+
+- **Catalog modal**: Providers tab → **Add provider** → pick an entry → it PATCHes the config (`extends:'acp'` + label + command, enabled) and refreshes that provider.
+- **Hand-edit** `data/coder-providers.json`: add an id with `extends:'acp'`, `label`, and `command`, then `POST /api/providers/refresh`.
+
+Either way, **adding to config does NOT install the binary.** Until the CLI is on `PATH` the provider shows **"Not installed"** (status `unavailable`) and does not appear in the composer picker.
+
+### Known limitation — subset refresh
+
+`POST /api/providers/refresh` accepts an optional `{ "providers": ["id", ...] }` body and returns a `refreshed` count scoped to that subset — **but the underlying cold re-probe currently covers ALL installed providers**, not just the requested subset. True per-provider force is a future change (it needs a snapshot-internal parameter). This is intentional for now, not a bug: a subset refresh still re-probes everything; only the reported count is scoped.
+
+### Deploy + smoke
+
+Two deploy targets:
+- **Routes (host service):** `pnpm -C packages/contracts build && pnpm -C apps/server build && pnpm -C apps/coder build && sudo systemctl restart boocoder`
+- **Web UI (container):** `docker compose up --build -d boocode`
+
+Green gate (verified across phases 1–5): `pnpm -C apps/coder test` (134 passing) `&& pnpm -C apps/coder build`.
+
+Smoke (via Tailscale):
+
+```bash
+curl http://100.114.205.53:9502/api/providers/snapshot       # lists every registered provider
+curl http://100.114.205.53:9500/api/coder/providers/config   # raw config, through the BooChat proxy
+# Settings → Providers: disable goose → it leaves the composer picker, stays in the tab
+# POST refresh → models repopulate; Add a catalog entry → it appears after refresh (unavailable until its CLI is installed)
+```
+
+## Persistent agent sessions (v2.6)
+
+When you `dispatch_external_agent` to a chat-tab provider, BooCoder keeps that agent **warm and resumable** instead of spawning a fresh process per turn. This is mostly transparent — but the model below explains why turn 2 is fast, why an external agent remembers earlier turns, and how edits flow.
+
+### Backends and keying
+
+- One live backend per **`(chat_id, agent)`** pair, owned by the `agent-pool` (`agent-pool.ts`). State lives in `agent_sessions` (the resumable session id) and `worktrees` (the per-chat working copy).
+- **opencode** runs a long-lived `opencode serve` (`backends/opencode-server.ts`) with per-session SSE; turns after the first reuse the same session (memory intact, ~9× faster).
+- **goose / qwen** run a warm ACP connection (`backends/warm-acp.ts`) — `initialize` + `session/new` once per `(chat,agent)`, then `session/prompt` per turn. Interrupt cancels the prompt (`session/cancel`), never the child.
+- **claude** runs the Claude Agent SDK backend (`backends/claude-sdk.ts`) over a clean-room Postgres session store.
+- Arena, MCP `new_task`, and one-shot dispatches still use the cold `runExternalAgent` path — warm reuse needs both a `session_id` and a `chat_id`.
+
+### Worktrees
+
+- External agents write **directly into a persistent per-chat worktree** (`/tmp/booworktrees/sess-<id>`), not into the project root via `pending_changes`. The worktree is created once, base commit captured, and **reused across turns and across agents in the same chat** — so opencode and goose in one chat share one worktree.
+- Each turn's worktree diff supersedes the prior `pending_changes` row for that `(chat,agent)` (latest-wins) and is badged with the authoring agent in the DiffPanel.
+- **Staging boundary:** a provider only sees another agent's edits once they are **applied**. Unapplied worktree edits from a different agent are invisible to you — the DiffPanel shows a muted hint when that's the case.
+
+### Lifecycle (v2.6.10–v2.6.11)
+
+- **Idle eviction:** a backend idle past `AGENT_POOL_IDLE_TTL_MS` (default 30 min) is disposed; an LRU cap of `AGENT_POOL_MAX_LIVE` (default 10) bounds live backends. A busy backend is never evicted, and the next turn transparently re-attaches or re-creates from `agent_sessions`/`worktrees`.
+- **Crash recovery:** a health monitor restarts a crashed server (opencode → fresh sessions; ACP → re-`session/new`) and reclaims its port.
+- **Close cleanup:** closing/deleting a chat or session evicts its backends, archives the `worktrees` row, and removes the worktree. An hourly reaper sweeps orphaned worktrees (dirty/unpushed preflight before removal).
+
+### Checkpoints (v2.7.1)
+
+Because external agents write the worktree directly (outside `pending_changes`), a worktree **checkpoint** is shadow-committed before each external-agent turn (tracked + untracked, into `refs/boocode/checkpoints/<id>`), anchored to that turn's assistant message. The per-message **"Restore to here"** affordance resets the worktree (`reset --hard` + `clean -fd`), trims the transcript past that message, and resets the `(chat,agent)` backend session — so files, transcript, and agent context land consistent at the restore point. `rewind` still only reverses BooCoder's own applied `pending_changes`; checkpoints are what cover external-agent worktree edits.
+
+### Normalized status (v2.6 / v2.7.6)
+
+Turn boundaries publish a normalized per-`(chat,agent)` status — `working | blocked | idle | error` — to the UI (`agent_status_updated` frame), so blocked-on-permission and crash/idle are visible, not just WS liveness.

CHANGELOG.md

@@ -2,6 +2,174 @@
 
 All notable changes per release tag. Most recent on top, ordered by tag creation date (which matches the git history). Tag names follow `vMAJOR.MINOR.PATCH-slug` — the slug describes what shipped, so the tag name alone is enough to recall the batch.
 
+## v2.7.16-container-git-safedir — 2026-06-03
+
+Hotfix that makes the `v2.7.15-git-diff-panel` work in production. The `boocode` container runs as root but bind-mounts host project repos owned by uid 1000, so git rejected them with "detected dubious ownership" and the diff route reported every project as not-a-repo — which hid the Git tab entirely (and had been silently nulling the existing branch indicator too). Adds `git config --system --add safe.directory '*'` to the Dockerfile runtime stage so the container's git trusts the mounted repos; applied live to the running container and baked into the image for future rebuilds. Surfaced by a live smoke immediately after the v2.7.14/v2.7.15 deploy.
+
+## v2.7.15-git-diff-panel — 2026-06-03
+
+A Files / Git tab in the right-side file panel (the file-browser sidebar) that shows the project repository's git diff and lets the user stage, unstage, commit, and discard whole files in-session — modeled on Paseo's diff view, scoped and planned through the `plan-a-feature` → `plan-implementation` skills, then built and audited via `paseo-epic` in an isolated worktree. Two comparison modes (Uncommitted vs HEAD, and the current branch vs its base — the upstream tracking branch else `origin/HEAD`), auto-selected by repo dirty-state on first open and pinned after an explicit choice; per-file expand/collapse with lazy Shiki `lang:'diff'` highlighting, +/- stats, and binary/too-large placeholders. All git read and write logic lives in `apps/server` (new `git_diff.ts` + routes on `projects.ts`) — the read-only-server posture governs the assistant's tools, not the user's own actions, and the container already mounts `/opt` read-write while `project_bootstrap` already commits via `execFile`. Every write uses the safe `execFile` argv pattern (never a shell string) with `--` operand separators, per-file `pathGuard` + realpath symlink-escape validation, server-derived `-c` commit identity (the request body is `.strict()` and carries no author fields), and the write endpoints are deliberately absent from the assistant tool registry. Reads are bounded (30s deadline, 10MB); an index lock or an in-progress merge/rebase/cherry-pick/bisect surfaces as "repository busy" and disables writes. The panel stays current via a client `git_diff_refresh` sessionEvent (no new wire contract) coalesced across tab-open, mutations, turn completion, and pending-change apply; discard is an irrecoverable hard-delete behind a plain confirm distinguishing a tracked revert from an untracked delete. New `git_diff` pure-helper + temp-repo integration tests (59 cases); server 630 tests green, web tsc clean. Pairs with `v2.7.14-backlog-hardening` (shipped together).
+
+## v2.7.14-backlog-hardening — 2026-06-03
+
+Five independent items from the second external-code-review backlog (`boocode_code_review_v2.md`), each built and audited as its own phase via `paseo-epic`. **External task-cancel** now actually works: Stop on an opencode/goose/qwen/claude task aborts the running child via a per-task `AbortController` registry reachable from the cancel route and finalizes the assistant message as `cancelled` — fixing two latent bugs (catch blocks left the message `streaming`; warm success-paths wrote `complete` on an aborted turn); warm pools/worktrees are preserved (abort the prompt only, never the pooled process) and the native boocode path is unchanged. **Parser prune**: the tool-call parser drops to its two load-bearing exports (eight zero-caller symbols unexported, a gate test added for the `<invoke>`-as-text fallback) with no live-path behavior change, and placeholder-rejection logging moves to pino. **BooChat stall-timeout**: a 90s per-chunk deadline wraps native inference's `fullStream` via `AbortSignal.any` so a hung local stream finalizes the message instead of hanging — no retry, since re-running re-emits already-streamed deltas (a pure `classifyStreamError` helper is added). **view_session_history**: a read-only MCP tool returning the newest-N transcript (role≠system) in chronological order. **Retire :9502**: the unused `apps/coder/web` fallback SPA is removed (package, static-serve block, build step, Dockerfile copy, `@fastify/static`), keeping every API/WS/health/MCP route. F1 added an optional `status` field to the shared `message_complete` contracts frame (so a deploy rebuilds `@boocode/contracts` first, as the sequence already does). Server 630 / coder 360 tests green.
+
+## v2.7.13-contracts-ssot — 2026-06-02
+
+Creates `@boocode/contracts` (`packages/contracts`), a new workspace package that becomes the single source of truth for every cross-app wire contract — reversing the decision recorded in `v2.5.12-provider-lifecycle-phase4` that declined a shared types package as not worth the Docker/build-order risk at solo scale; a live `AgentSessionConfig` drift that had since appeared between `apps/coder` and `apps/web` justified the investment. Six contracts are now defined exactly once: the `WsFrameSchema` Zod runtime schema, the provider snapshot types (`ProviderSnapshotEntry` and family), the Zod provider-config schemas, `MessageMetadata` + `ErrorReason`, `AgentSessionConfig`, and `WorktreeRiskReport`; both Zod-backed contracts use `z.infer` so validator and type derive from the same definition and cannot drift independently. All four consumers — `apps/server`, `apps/web`, `apps/coder`, and the fallback SPA `apps/coder/web` — import via `workspace:*` through a per-subpath exports map consuming built dist only (no tsconfig project references); the hand-synced copies and their parity tests (`provider-types-parity.test.ts`; the ws-frames byte-parity assertion) are deleted while the KNOWN_FRAME_TYPES drift test and broker fail-closed tests are preserved. Build order is inverted in the root build script, Dockerfile, and coder deploy docs; `apps/coder/web`'s migration also removed dead `pending_change_*` reducer arms (no frame publisher exists for these — pending changes are HTTP-delivered), closing a latent missing-default-arm crash, and reconciled field-type conflicts with the canonical `WsFrame`; zod is pinned to a single version across the workspace. Server 543 / coder 293 / contracts 11 tests passing; human smoke verified on the live stack 2026-06-02.
+
+## v2.7.12-audit-cleanup — 2026-06-02
+
+A repo-wide audit and aggressive cleanup pass, run as a multi-agent orchestration (five read-only Opus auditors over server/web/coder/booterm + cross-cutting deps/build/parity + a structural-architecture lens) followed by phased, behavior-preserving implementation — every change gated on the per-app test suites and delivered behind a strict DEFER discipline that never touched the files in flight for `v2.7.9`–`v2.7.11` (`mcp-config`, the `ws-frames` pair, `dispatcher`, `claude-sdk-map`, `AgentComposerBar`/`CoderMessageList`/`CoderPane`), so the branch rebased onto current main with zero conflicts. **Dead code/deps/schema**: removed ~9 dead files and a swathe of dead exports/write-only state across all four apps, dropped dead deps (`next-themes`, `@xterm/addon-webgl`, booterm `tslib`; `shadcn`→devDep), and idempotently dropped dead schema columns/tables (`sessions.tags`, `tasks.worktree_path`/`feature_values`, `available_agents.supports_mcp_client`, the superseded `session_worktrees` table, the always-empty `list_worktrees` MCP tool) — chat/session/message DATA untouched, only never-read columns. **Server dedup + reshapes**: collapsed the dead `budget.ts` tier system (surfacing a latent `READ_ONLY_TOOL_NAMES` drift, then deleted), extracted shared `MESSAGE_COLUMNS`/`selectProject`/`stripQuotes`/`SENTINEL_KINDS`/`samplerOptsFromAgent`/`createContentFlusher`/`insertSentinel`/a `makeCodecontextTool` factory/a pending-tool-call resolver, split `tools.ts` (799→46 barrel + `tools/{types,fs-tools,misc-tools,registry,tiers}`, register-through registry preserved so coder's import contract stays byte-stable), and decomposed the inference pipeline (`sentinel-summaries`→`runWrapUpSummary`, `turn.ts`→`turn-config`+`step-decision`, a pure `stream-phase-adapter`, shared finalize atoms — stopping short of fusing synthesis to preserve frame timing). **Coder reshapes**: split the 1062-line `opencode-server.ts` god-class into supervisor / sse-loop / pure event-map / port-utils + extracted `buildAcpClient`/`makeFrameEmitter`/`worktree-risk`, plus happy-path-safe concurrency hardening (reconnect backoff, double-spawn guard; a defensive busy-assert + ensureSession coalescing flagged for review). **Web**: `React.memo` on `MessageBubble`/`MarkdownRenderer` + module-hoisted markdown components (the streaming re-parse was the biggest perf cost), shared `linkifyPaths`/artifact/tab dedup, two latent bug fixes (`ChatPane` index-keys → stable ids; `FileViewerOverlay` blank-line line-number desync), and decomposed the 1298-line `TerminalPane.tsx` into fit/socket/selection hooks + presentational pieces (verbatim move, all ~30 listeners/timers inventoried; the label-dep fix stops a live terminal tearing down on pane renumber). +78 parity/unit tests (server 597, coder 328 green; `apps/web` has no harness, so its changes are typecheck + manual/device QA). Net ≈ −4,600 LOC. Deferred (designed; blueprints in the audit reports): the `tasks` dual-CREATE / `project_id` FK (a cross-service deploy-ordering decision, not a data migration), web structural decomposition of `useWorkspacePanes`/`MessageBubble` (needs a web test harness first), a `@boocode/contracts` shared package, and the `dispatcher.ts` split — the last two now unblocked since their in-flight files shipped in `v2.7.9`–`v2.7.11`. Rebased clean onto `v2.7.11-coder-model-snapshot`.
+
+## v2.7.11-coder-model-snapshot — 2026-06-02
+
+Hotfix for the coder model-attribution chip vanishing on refresh. The chip showed during a live turn (the `message_complete` frame carries `model`) but disappeared when a BooCoder session was reloaded — only in the coder, not BooChat. Root cause: `CoderPane`'s `useCoderMessages` hydrates from two sources on load — the HTTP `listMessages` fetch (whose SELECT includes `model`, added `v2.7.8`) AND the WS `snapshot` frame — and the WS snapshot's query in `apps/coder/src/routes/ws.ts` had its own column list that omitted `model`. The client's `snapshot` handler `setMessages`-overwrites the HTTP load, so the model-less rows won, and with no later `message_complete` for historical messages the chip stayed gone. Fix is one column: add `model` to the WS snapshot SELECT so both hydration paths agree. The `apps/coder/CLAUDE.md` "update every mapper" note now lists the WS snapshot SELECT explicitly (it was the one place not enumerated). apps/server + apps/coder builds green; deployed via `systemctl restart boocoder` (host service — the earlier `v2.7.10` docker deploy rebuilt only the container, never this route). Fixes the chip shipped in `v2.7.8-ember-coder-tabs-model-chips` / completed in `v2.7.9-mcp-keys-docs-coder-fixes`.
+
+## v2.7.10-composer-chips — 2026-06-02
+
+A composer control-row refresh shared by BooChat and BooCoder via `ChatInput`. The slash-commands menu moves out of the full-width `AgentCommandsHint` disclosure (now removed) into a compact chip in the message box's bottom controls row — clicking it opens the existing `SlashCommandPicker` anchored to the chip and selecting inserts `/<name> `, while the typed-`/` autocomplete is unchanged. A new attach-file button sits beside it, opening a native multi-file picker that funnels picks through the same drag-drop pipeline (5 MB / binary gate, 10-attachment cap, chips + preview, `source:'drop'`). On mobile both collapse to icon-only — the slash count is `max-md:hidden` and the paperclip is icon-only — so the row stays on one line per the no-scroll toolbar rule. Web tsc + build green; deployed (docker). Builds on the BooCode 2.0 composer work in `v2.7.8-ember-coder-tabs-model-chips`.
+
+## v2.7.9-mcp-keys-docs-coder-fixes — 2026-06-02
+
+The MCP-key hygiene feature plus accumulated in-flight coder fixes and a docs refactor. **MCP `{env:VAR}` substitution** (`mcp-config.ts:substituteEnvVars`, opencode-compatible) recursively resolves `{env:NAME}` references in any string value of `data/mcp.json` from `process.env` *before* Zod validation, so real keys live in `.env` (`env_file`) instead of the gitignored config — an unset var resolves to `''` with a boot-log warning, and on a validation failure the loader names the unset vars alongside the field errors (an empty `{env:VAR}` in a strict url/command field invalidates the whole config, an otherwise-disconnected warning). `data/mcp.json` is now untracked (`.gitignore` flips `!data/mcp.json` → `!data/mcp.example.json`); the tracked template `data/mcp.example.json` carries `"CONTEXT7_API_KEY": "{env:CONTEXT7_API_KEY}"` and `.env.example` documents the key (9 mcp-config tests). **Two coder bug fixes** ride along: the `message_complete` frame's `model` is widened `string` → `string | null` in both ws-frames copies (server + web parity) and the dispatcher now publishes `model: task.model` at all four external assistant-completion points — without the nullable widen a null model would fail-closed in `publishFrame` and drop the entire frame including the `status:'complete'` transition (regression test added); and Claude-SDK `mapUserToolResults` now maps `user`-message `tool_result` blocks → terminal `tool_update` events (completed/failed with output) so external-agent tool snapshots resolve instead of spinning forever (the SDK feeds tool output back as a user message, previously unmapped). On the view side the `AgentComposerBar` drops the §9b resumed/history/new-session chip and token-usage readout and loses `flex-wrap` so the control row stays on one line, while `CoderPane` gains a per-chat `localStorage` agent-config cache (provider/model/mode/thinking keyed by chat id, restoring the last model on reopen) and threads the new `model` field into the timeline + attribution chip. **Docs refactor**: the root `CLAUDE.md` is slimmed (~190 lines) with per-app deep references split into `apps/{coder,server,web}/CLAUDE.md` (auto-loaded in-subtree), plus a new 372-line `docs/coder-backends.md` dispatch reference, a `docs/project-discovery.md` stack inventory, and a `docs/coding-standards/` set (the `cross-app-contract-parity` standard, fronted by `.claude/rules` path-scoped indexes) — `ARCHITECTURE.md` links the backends doc. Server 555 + coder 299 tests passing (incl. new mcp-config, ws-frames, and claude-sdk-map suites), web tsc + server + coder builds green. Builds on `v2.7.8-ember-coder-tabs-model-chips`.
+
+## v2.7.8-ember-coder-tabs-model-chips — 2026-06-01
+
+The BooCode 2.0 visual identity plus two workflow features. **Ember theme** (`styles/themes/ember.css`, now `DEFAULT_THEME_ID`) is the signature orange-on-near-black look — rebuilt on Obsidian's flat charcoal structure (`#0c0c0e`/`#15151a`/`#1f1f23`) with `#ff7a18` swapped in for the purple, after a Reinvented-direction detour (neon borders + a scanline/glow texture overlay) was dialed back to taste; the server `theme_id` whitelist gains `ember` so it can actually be selected. The **brand banner** (`ProjectSidebar`) shows the eye-patch Westie mascot + the `>_BooCode` wordmark big and edge-to-edge on transparent backgrounds — the source PNGs shipped with baked-white canvases, so they were flood-filled to transparency from the corners (preserving the white dog, which a naive white-key would have destroyed) and cropped to bounds. **Coder panes are now multi-tab**: `+` opens a new BooCode tab (a fresh chat = a new agent context sharing the session worktree) while the split button still opens a pane — coder panes reuse the shared `ChatTabBar` via a kind-aware `tabKind`, backed by a new `createCoderTab` action with `closeOtherTabs`/tab-numbering extended to coder kind. **Model-attribution chips**: a new `messages.model` column (both apps share the table) stamped at `finalizeCompletion` (BooChat + native coder) and at the dispatcher's assistant-row creation (external coder), surfaced through the `messages_with_parts` view + wire types + the live `message_complete` frame (the Zod already allowed `model`; nothing consumed it), and rendered as a subtle accent chip with a shortened label (`shortenModelName` → `Sonnet 4.6`, `Qwen3.6 35B`) beside the message stats — so swapping models mid-coder-session stays legible. Also the composer moved its Web toggle into a boxed, focus-ringed input, tool rows lead with a glowing accent dot, and the Claude-SDK-backend follow-ups validated live this session (1M context window, follow-up-message fix, collapsed thinking/tool chips) land with `CLAUDE_SDK_BACKEND=1` flipped on. One snag fixed mid-deploy: the view's new `m.model` was first inserted mid-list and `CREATE OR REPLACE VIEW` can't reorder columns (42P16) — appended at the end. Web tsc + server + coder builds green; deployed (docker + boocoder, tools:34). Builds on `v2.7.7-pane-header-actions`.
+
+## v2.7.7-pane-header-actions — 2026-06-01
+
+In-flight workspace UX work, committed alongside the v2.7 review batches. Extracts a shared `PaneHeaderActions` cluster (the +/Split/Reopen-closed-pane/Session-history/Close controls) used across the `ChatTabBar` and the desktop coder + terminal pane headers in `Workspace`, replacing the divergent per-header copies, with `SessionLandingPage` history enhancements and `useWorkspacePanes` tweaks. Also fixes a coder-side correctness bug: `resolveChatId` (`apps/coder/src/routes/chat-resolve.ts`) still read `sessions.workspace_panes` as a bare `WorkspacePane[]`, but `v2.6.5-panes-tabs-composer` widened it to a `WorkspaceState` envelope — so it mis-read the panes and, worse, clobbered `tabNumbers`/`nextTabNumber`/`closedPaneStack` back to a bare array on every pane-chat write; a new `normalizeWorkspaceState` accepts either shape and preserves the envelope (with a regression test). Plus a CLAUDE.md doc-sync (apps/coder vitest suite, deploy-by-surface, dual-remote push, in-flight-web-WIP staging, release-branch naming). Web tsc + coder build + coder tests green. Builds on `v2.7.6-agent-status-normalize`.
+
+## v2.7.6-agent-status-normalize — 2026-06-01
+
+The scoped half of `boocode_code_review_v2.md` §1 #10 — normalized external-agent status, surfaced from BooCoder's own dispatch observation (the heavier config-injection notify-hook, clean-room from superset's ELv2 `agent-setup`, is documented as the follow-on). The review's premise ("PTY agents have no status") had partly aged out — warm-ACP/opencode/SDK already carry working/done — so the real gap was that BooCoder never *published* a normalized per-`(chat,agent)` status (blocked-on-permission was invisible; crash/idle weren't pushed). Adds an `agent_status_updated` WS frame (`working|blocked|idle|error`, server+web parity) published from the dispatcher's turn boundaries across all four external paths (warm-acp/opencode/sdk/pty — `working` at start, `idle`/`error` at end) and the permission flow (`blocked` on request, `working` on resolve), best-effort so it never breaks a turn. A clean-room `normalizeAgentEvent` helper (superset's ~30-vendor-event → Start/blocked/Stop collapse, reimplemented with the event names as facts) ships now with 25 tests so the deferred notify-hook injection reuses it verbatim. The `AgentComposerBar` gains a normalized status dot (working=spinner, blocked=amber, idle=gray, error=red) distinct from the WS-liveness dot, fed by a `useAgentStatus` map `CoderPane` tracks per `(chat,agent)`. Built by two parallel agents (data plane + view plane) against a pinned frame contract; server 545 + coder 294 tests passing (25 new), web tsc + builds clean, ws-frames parity green. Clears the actionable review backlog (#1/#3/#4/#6–#12). Builds on `v2.7.5-claude-sdk-sessionstore`; openspec `agent-status-normalize`.
+
+## v2.7.5-claude-sdk-sessionstore — 2026-06-01
+
+Lands the Claude Agent SDK direction (`boocode_code_review_v2.md` §1 #9, §6.2 "lean SDK") behind a flag. Adds `@anthropic-ai/claude-agent-sdk@0.3.159` (Commercial Terms — runtime dep, code reference-only) and builds a warm, resumable claude backend to supersede one-shot PTY dispatch — env-gated (`CLAUDE_SDK_BACKEND`, default off) so production claude stays on the unchanged PTY path until a host smoke. **Clean-room `PostgresSessionStore`** implements the SDK's real `SessionStore` type (`append`/`load`/`listSessions`/`delete`/`listSubkeys`) over a new `claude_session_entries` table — typechecked against the installed SDK type, 8 DB-integration tests. **`ClaudeSdkBackend`** (`implements AgentBackend`, mirroring warm-acp/opencode-server) drives one persistent `query()` per `(chat,'claude')` in streaming-input mode via a pushable async-iterable pump, with `sessionStore` + `resume` for cross-turn/cross-restart continuity, a pure `mapSdkMessage`→`AgentEvent` mapper, `session_id` captured from the `init` message, and `result.usage`/`total_cost_usd` accumulated onto `agent_sessions` (backend CHECK gains `'claude_sdk'`). Built against the REAL SDK 0.3.159 types after installing it — surfacing shapes a blind build would have missed (`SDKPartialAssistantMessage` is `type:'stream_event'` needing `includePartialMessages`; `SDKUserMessage.message` is `MessageParam`; the `SDKResultMessage` error arm). Also fixes a latent test-infra deadlock — three DB-integration suites applying the full schema in parallel under `DATABASE_URL` deadlocked, now serialized via `fileParallelism:false`. ~32 new tests (8 store + 10 mapper + 8 pushable + 6 routing); coder suite 269 passing default / 290 with DB; tsc clean against the SDK types; builds clean. **The live streaming pump + resume + an actual claude turn need a host smoke (`CLAUDE_SDK_BACKEND=1` + claude binary + ANTHROPIC auth) — cannot run from the dev container.** The zod peer-dep wants `^4` (workspace `3.25`) — watch at runtime. Builds on `v2.7.4-mistake-tracker-ledger`; openspec `claude-sdk-sessionstore`.
+
+## v2.7.4-mistake-tracker-ledger — 2026-06-01
+
+Two native-inference hardening features from `boocode_code_review_v2.md` §1 #12 (cline, algorithm-reimplemented). **MistakeTracker:** complements the doom-loop guard (identical repeats) and cap-hit (budget) by catching a run of consecutive tool *failures*. A new pure `mistake-tracker.ts` tracks heterogeneous failure kinds (`zod_reject`/`tool_not_found`/`exec_error`/`api_error`/`permission_denied`, surfaced per tool from `tool-phase.ts`); after 3 consecutive failures the `turn.ts` loop does a **soft nudge** — injects model-facing recovery guidance into the next step + drops a `mistake_recovery` UI sentinel + resets — then **escalates** to stopping the turn (cap-hit-style, with a Continue affordance) if it re-trips without an intervening success, so heterogeneous failures can't burn the whole step budget. **File-provenance ledger:** `compaction.ts` now derives a deterministic, sorted `## Files Read` list from the head messages' read-tool calls (`view_file`/`grep`/`find_files`/`list_dir`) and injects it into the rolling-summary prompt so file provenance survives compaction (no new table; prompt-driven merge, read-only since BooChat has no write tools). The `mistake_recovery` sentinel adds an arm to `MessageMetadata` in both server + web type copies plus a `MessageBubble` render branch. Built by two parallel agents (backend + frontend sentinel) over disjoint apps; server 545 tests passing (23 new: 12 mistake-tracker + 11 compaction), build + web tsc clean. Native-inference only (external agents run their own loops). Builds on `v2.7.3-sampling-streamjson-tokens`; openspec `mistake-tracker-file-ledger`.
+
+## v2.7.3-sampling-streamjson-tokens — 2026-06-01
+
+Three small BooCode wins from `boocode_code_review_v2.md` §1 #11/#7/#8. **Sampling knobs:** per-agent `top_n_sigma` + the `dry_*` repetition family (`dry_multiplier`/`dry_base`/`dry_allowed_length`/`dry_penalty_last_n`) are now first-class Agent frontmatter fields, parsed in `agents.ts` and threaded into the llama-swap chat-completion body via `providerOptions.openaiCompatible` (the `@ai-sdk/openai-compatible` extra-body channel). This surfaced and fixed a **latent bug**: `top_k` (rejected by the AI-SDK provider as unsupported) and `min_p` (never passed to `streamText` at all) had been dead on the wire — no agent's `top_k`/`min_p` ever affected sampling; both now route through the same channel, so agents that set them will start using them. `--reasoning-budget` is documented in `data/AGENTS.md` (already works via `llama_extra_args`, permitted by the deny-list validator). **Live PTY stream-json:** qwen/claude PTY dispatch sliced stdout opaque; a new `stream-json-parser.ts` line-buffers the Claude-Code-compatible NDJSON and emits text/reasoning/tool frames live as they arrive (mirroring the ACP/opencode paths) + persists the structured parts, with a clean fallback to the old opaque slice when output isn't NDJSON (claude now runs `--output-format stream-json --verbose`). **Token UI:** the per-`(chat,agent)` `agent_sessions.input_tokens`/`output_tokens`/`cost` columns (accumulated since `v2.6.8` but dropped by the read route + wire type) now flow through and render condensed beside the AgentComposerBar session chip. Built by three parallel agents over disjoint subsystems; server 523 + coder 245 tests passing (incl. 11 new stream-json-parser + new agent-parse tests), all builds + web tsc clean. Builds on `v2.7.2-checkpoint-idor`; openspec `sampling-streamjson-tokens`. The qwen-vs-claude `usage` field names in #7 are best-guess pending a live smoke.
+
+## v2.7.2-checkpoint-idor — 2026-06-01
+
+Closes two IDOR authorization holes in the `v2.7.1-write-edit-robustness` checkpoint routes, flagged by the automated push security review. The `GET /api/sessions/:id/checkpoints?chat_id=` list route scoped its `chat_id` branch by `chat_id` alone — any session's `chat_id` would read its checkpoints; it now joins through `chats` and gates on `chats.session_id` (authoritative; `checkpoints.session_id` is a nullable denormalized hint). The `restoreCheckpoint` scope guard was fail-open — `cp.session_id && cp.session_id !== sessionId` fell through whenever the checkpoint's denormalized `session_id` was null, allowing a cross-session restore (worktree reset + transcript trim) — it now resolves the owning session via the checkpoint's chat and denies on any missing-or-mismatched row. A DB-integration regression covers the exact null-`session_id` cross-session case. Real-world blast radius is small (BooCoder is single-user behind Authelia on loopback), but both are genuine authorization bugs. Coder suite 234 passing (7/7 checkpoint tests incl. the regression against live postgres+git), typecheck clean. Hotfix on `v2.7.1-write-edit-robustness`.
+
+## v2.7.1-write-edit-robustness — 2026-06-01
+
+Two BooCoder hardening features for local quantized models, algorithm-reimplemented (not vendored) from the cline findings in `boocode_code_review_v2.md` §1 #3/#4. **Fuzzy patch applier:** `edit_file`'s apply path was exact-`.includes`-or-throw + first-occurrence `.replace` (`pending_changes.ts`), so a qwen3.6 whitespace/indentation/unicode drift in `old_string` lost the edit; a new pure `fuzzy-match.ts` (`locateMatch`) now runs an exact → per-line-trim → unicode-canon (curly quotes/dashes/nbsp) → Levenshtein-≥0.66 ladder and returns the real file span, refusing multi-exact matches as ambiguous rather than silently editing the first. `applyOne`/`rewindOne` both use it. **Worktree checkpoints + conversation-trim:** `rewind` only reversed BooCode's own `pending_changes`, blind to what external agents (opencode/goose/qwen/claude) write directly into the session worktree — so a new `checkpoints` table + `checkpoints.ts` shadow-commit (tracked **and** untracked, captured via a temp-index `read-tree`/`add`/`write-tree`/`commit-tree` into a GC-safe `refs/boocode/checkpoints/<id>`) snapshots the worktree before each external-agent turn (hooked into all three dispatcher paths), anchored to the turn's assistant message. A new `POST /api/sessions/:id/checkpoints/:cid/restore` resets the worktree (`reset --hard` + `clean -fd`), trims the transcript past that message, and resets the `(chat,agent)` backend session so files, transcript, and agent context land consistent at the restore point; a per-message "Restore to here" affordance in `CoderMessageList` drives it. Built by three parallel agents over disjoint files; DB-integration testing caught a microsecond-`created_at` self-deletion bug in the later-checkpoint cleanup. Full coder suite 234 passing (incl. 17 fuzzy-match + 6 checkpoint tests), server+coder build + web tsc clean. Builds on `v2.7.0-mit`; openspec `write-edit-robustness`. Live host smoke (dispatcher hook + restore UI end-to-end) still to run.
+
+## v2.7.0-mit — 2026-06-01
+
+Relicenses BooCode from AGPL-3.0 back to MIT by clearing the three Unsloth-Studio-derived files the `v2.4.0`/`v2.4.1` lifts pulled in — the root `LICENSE` and all five `package.json` had been `AGPL-3.0-only`, making the network-served work AGPL §13-encumbered. The enabling finding decoupled the relicense from the long-planned native-llama-server-parsing retirement: `tool-call-parser.ts`'s Unsloth-ported algorithm (`parseToolCallsFromText`/`scanBalancedBraces` + unused nudge constants) was **dead code** with no production import, so it was simply deleted while the load-bearing `extractToolCallBlocks`/`stripToolMarkup` (BooCode-authored streaming helpers) were kept byte-identical — no behavior change to the live tool-call path. `html-to-md.ts` was swapped to the MIT `node-html-markdown` library (`parse5` dropped; the only behavior delta is column-aligned tables, GFM hard-break `<br>`, and `<ol start>` renumbering, all feeding the LLM via `web_fetch`), and `llama-args-validator.ts` was clean-room rewritten with the managed-flag denylist re-derived from the public llama-server flag list (facts, not copyrightable). The license flip set `LICENSE` to MIT (`Copyright (c) 2026 indifferentketchup`), the five `package.json` to `MIT`, removed every AGPL SPDX header, added a README License section, and added a `license-mit` guard test that fails if AGPL provenance returns. Built by three parallel agents over the disjoint files; full server suite 519 passing (incl. 9 new guard tests), server build + coder typecheck clean. Resolves `boocode_code_review_v2.md` §1 #1 / §5k and the roadmap's `License-debt` batch (openspec `license-debt-mit`); supersedes that batch's original staged plan, which had entangled the flip with a live qwen3.6 validation window.
+
+## v2.6.11-close-hooks-staging — 2026-06-01
+
+The two v2.6 follow-ups left after `v2.6.10-lifecycle-hardening`. **Server close-hook caller:** `apps/server` (BooChat) now fire-and-forgets BooCoder's Phase-3 close hooks so warm agent backends + worktrees tear down *immediately* on delete/archive instead of waiting for the idle-evict/reaper backstop — a new `coder-notify.ts` `notifyCoderClose(kind,id)` (reusing the v2.6.2 `BOOCODER_URL` reach, never-rejects) is `void`-called after the WS frame at session-delete (`POST /api/sessions/:id/close`) and chat archive / archive-all / delete (`POST /api/chats/:id/close`); an unreachable coder can never block or fail the user's delete/archive. **Staging-boundary hint (task 3.7):** the BooCoder DiffPanel now shows a muted one-liner when the selected provider can't see another agent's unapplied worktree edits — native boocode selected + external-agent-staged changes (or vice-versa) → "<agent>'s edits live in its worktree — BooCode won't see them until applied" — derived purely from the per-change `agent` + current provider, no new state. 6 new server tests (`coder-notify`), 537 server tests pass; web + server tsc/build clean. **With these the v2.6 openspec is fully closed** — only the live Smoke 2/2b/3 remain (manual exercise).
+
+## v2.6.10-lifecycle-hardening — 2026-06-01
+
+v2.6 Phase 3 (the last phase) — lifecycle hardening of the warm-process backends. **Idle eviction + LRU cap:** the agent pool runs a 60s sweep that evicts backends/sessions idle past `AGENT_POOL_IDLE_TTL_MS` (30 min default) and any beyond `AGENT_POOL_MAX_LIVE` (10, LRU) — **never a busy one** (in-flight turn, double-checked via a new `isBusy()` backend hook); the worktree persists (DB-backed) and the next turn re-spawns + reattaches. The eviction/LRU/restart decisions are factored into a pure `lifecycle-decisions.ts` (modeled on the inference `selectPruneTargets` pattern). **Crash recovery:** lifts openchamber's health-monitor + busy-aware-restart + consecutive-failure + stale-busy-grace state machine into `opencode-server.ts` (with port reclaim) and `warm-acp.ts` — an opencode server crash settles in-flight turns as failed, marks the rows `crashed`, and recreates fresh sessions (a fresh server can't hold the old in-memory id), while a warm-ACP child crash re-`session/new`s next turn; the F.1 turn-guard and U.6 usage are preserved (their tests still pass). **Worktree reaper:** a periodic reaper removes orphan on-disk worktrees (no live `worktrees` row, 1h grace) behind a superset-style preflight that skips dirty/unpushed/unmerged work, with Paseo-style soft-delete (`status='archived'`). Plus close hooks (`/api/chats/:id/close`, `/api/sessions/:id/close`, awaiting the apps/server caller) and diff re-baseline after `apply_pending`. Built test-first — 35 new tests (`lifecycle-decisions` 22, `agent-pool` 13) + a DB-opt-in reconnect integration test; 215 coder tests pass, tsc + build clean. **This completes v2.6** (Phase 0–3 + F.1 + Phase 1-UX). Remaining follow-ups (out of v2.6 scope): the apps/server close-hook caller, the 3.7 DiffPanel staging-boundary hint (frontend), and live Smoke 2/2b/3.
+
+## v2.6.9-warm-acp — 2026-05-31
+
+v2.6 Phase 2: goose and qwen now run as **warm ACP backends** instead of one-shot-per-task. A new `WarmAcpBackend` (`backends/warm-acp.ts`, implementing the same `AgentBackend` interface as the opencode warm server) holds one persistent `goose acp` / `qwen --acp` child + `ClientSideConnection` + ACP session per `(chat, agent)`, running `initialize` + `session/new` once and reusing the connection across turns; per-turn abort cancels the in-flight prompt (`session/cancel`) without killing the child, and a child exit marks `agent_sessions.status='crashed'` for re-spawn on the next turn. The dispatcher routes `goose`/`qwen` chat-tab tasks to the pooled warm backend via a pure `shouldUseWarmBackend(task)` predicate (warm only when both `session_id` and `chat_id` are set), keeping the one-shot `runExternalAgent` path as the fallback for session-less creators (arena, MCP, `new_task`); broker frames + `persistExternalAgentTurn` + the latest-wins `pending_changes` diff are identical to the opencode path. The `acp-dispatch.ts` `handleSessionUpdate` switch was extracted into a pure shared `acp-event-map.ts` mapper used by both the one-shot and warm paths (one-shot behavior byte-identical, all existing acp tests green). The design's `unstable_resumeSession` concern is resolved — the installed `@agentclientprotocol/sdk@^0.22.1` exposes stable `resumeSession`/`loadSession`, but resume is moot in the hot path (warm reuse needs none); cross-restart resume + idle eviction are deferred to Phase 3. Built test-first (15 new tests: `warm-acp-routing`, `acp-event-map`); 180 coder tests pass, tsc + build clean. **Smoke 2/2b (live two-message warm reuse + the opencode→boocode→opencode switch round-trip) to be run post-deploy.** Phase 3 (lifecycle hardening) is the last v2.6 phase.
+
+## v2.6.8-agent-attribution — 2026-05-31
+
+v2.6 Phase 1-UX: agent attribution + switch affordances over the already-shipped `pending_changes.agent` column and `agent_sessions` table (read+display, no new backend capability). **Backend:** `pending_changes.agent` is now stamped at every queue site (native write tools → `'boocode'`, dispatched external agents → the task's agent, manual RightRail create → `NULL`) and flows through `listPending`; a new `GET /api/sessions/:id/agent-sessions` route returns `[{agent,status,has_session,last_active_at}]` per `(chat,agent)` for the session's chats; and the opencode warm-server backend consumes opencode's `session.next.step.ended` events, accumulating `input_tokens`/`output_tokens`/`cost` onto the `agent_sessions` row (new columns, idempotent). **Frontend:** the BooCoder DiffPanel renders a per-row agent badge (provider icon + label; `null` → "manual") with a "Changes from X, Y" note when a pending set spans multiple agents, and the AgentComposerBar shows a resumed / history / new-session chip beside the Provider picker — gated on an optional `sessionId` prop so BooChat is unaffected — driven by a new `useAgentSessions` hook that refetches on message-complete; `providerIcon` was extracted to a shared `components/coder/providerIcons.tsx`. Built by three parallel subagents over disjoint file sets; web + coder typecheck clean, 165 coder tests pass (9 new across `opencode-usage` and `agent-sessions.routes`). U.6's persisted token totals are conversation-cumulative and not yet surfaced in the UI (deferred). Implements the U.1–U.6 "remaining" plan from the v2.6 openspec reconciliation; Phase 2 (warm ACP goose/qwen) + Phase 3 (lifecycle hardening) remain.
+
+## v2.6.7-interrupt-guard — 2026-05-31
+
+Fixes a post-interrupt correctness bug in the `v2.6.1-phase1-opencode` warm-server backend, made one-click reachable by `v2.6.5-panes-tabs-composer`'s Send→Stop composer. `opencode-server.ts` settled an in-flight turn on opencode's `session.idle`/`session.error` by calling `activeTurn.settle()` on whatever turn currently held the session slot — but opencode emits one trailing terminal event for a *cancelled* turn after `client.session.abort()`, and those events carry only a `sessionID` (no turn id). So after the user hit Stop and immediately sent another message, the aborted turn's orphan `session.idle` settled the *new* turn early as success (Paseo hit and fixed the same class in `1d38aac`). The fix adds a small pure guard (`turn-guard.ts`: `armAbortGuard`/`noteTurnActivity`/`consumeTerminal` over a per-session `swallowNextTerminal` flag): abort arms it, the next terminal is swallowed once, and a new turn's first delta self-heals the flag so a never-arriving orphan can't strand a real turn. Implemented test-first — three regression tests in `turn-guard.test.ts` (swallow-the-orphan, settle-when-no-abort, self-heal); full coder suite green (156 passed). This is the F.1 "fix-next" item from the v2.6 openspec reconciliation; Phase 1-UX / Phase 2 / Phase 3 remain.
+
+## v2.6.6-claude-md — 2026-05-31
+
+Docs-only — CLAUDE.md session-learnings update, no code. Captures four recurring gotchas surfaced while shipping `v2.6.5-panes-tabs-composer`: (1) `sessions.workspace_panes` is now a `WorkspaceState` envelope (`panes` + `tabNumbers`/`nextTabNumber` + `closedPaneStack`), migrated from the legacy bare `WorkspacePane[]` on both frontend hydrate (`toWorkspaceState`) and the union-accepting server PATCH validator; (2) DB/session-aware tools take an optional `ToolExecCtx` (`{ sql, sessionId }`) 4th arg on `ToolDef.execute`, plumbed through the tool phase, with `read_tab_by_number` as the reference; (3) the two-schema-files-one-DB ownership split — `apps/coder/src/schema.sql` owns `agent_sessions`/`worktrees`/`pending_changes`/`available_agents` and extends `tasks`, distinct from BooChat's `apps/server/src/schema.sql` — plus the idempotent `confdeltype` FK-action-flip pattern (guard `ON DELETE` changes on `pg_constraint.confdeltype` so re-runs no-op); and (4) React StrictMode is on, so a `setState` called inside another `setState`'s updater double-fires in dev and must be made idempotent. Pairs with `v2.6.5-panes-tabs-composer`.
+
+## v2.6.5-panes-tabs-composer — 2026-05-31
+
+A workspace UX batch across BooChat panes, tabs, and the composer, plus the persistence model that backs them. **Panes & tabs:** a chat can be opened in a fresh pane (the ChatTabBar tab context menu's "Open in new pane", and the fork button — which now lands the fork beside the original via a new `open_chat_in_new_pane` event instead of replacing the active pane); the per-pane "+" became a New BooChat/BooTerm/BooCode menu; closing a chat pane relocates its tabs (in order) into the oldest chat/empty pane instead of discarding them, and reopen strips the restored chatIds from every live pane first so a relocated-then-reopened pane never duplicates a tab (no stack-shape change); each tab carries a stable session-scoped number assigned on open and retired on close (never reused), rendered map-keyed rather than positional. The per-message "Open in pane" artifact button was removed, and the empty/landing pane became a real session history — the session's open chats plus separately-fetched archived chats, click to open or restore-and-open. **Persistence:** `sessions.workspace_panes` was widened from a bare `WorkspacePane[]` to a `WorkspaceState` envelope (`panes` + `tabNumbers`/`nextTabNumber` + `closedPaneStack`) so tab numbers and the reopen stack survive reload; the PATCH validator accepts the legacy array or the envelope (zod union) and migrates on write, and the `session_workspace_updated` WS-frame schema was widened on both web and server (byte-identical, parity test green) — the same schema-drift class as `v2.6.4-agent-sessions-fk`. **Composer:** the send button morphs Send → Stop → Queue with generation state (BooCoder keys on `sending || activeTaskId`, which also corrected its queue gates and added `cancelTask`), the standalone "Stop generating" pill was folded into it, and pasted chips now trail the typed text so a leading slash command stays first. **Tooling:** adds the read-only `read_tab_by_number` tool — resolves a session-scoped tab number to its chat via the persisted `tabNumbers` map and returns that chat's transcript; tools gained an optional `ToolExecCtx` (`{ sql, sessionId }`) on `execute` to support DB-reading tools. Builds on `v2.6.4-agent-sessions-fk`.
+
+## v2.6.4-agent-sessions-fk — 2026-05-31
+
+Follow-up to `v2.6.3-chatkey-and-skills` (P1.5-b): the live `agent_sessions.session_id` foreign key is converged from `ON DELETE CASCADE` to `ON DELETE SET NULL`, matching the schema's stated intent. The P1.5-b re-key block re-adds `session_id_fkey` as `SET NULL`, but the whole block is guarded on `chat_id_fkey`'s absence — so a database already re-keyed to `(chat_id, agent)` while `session_id_fkey` was still `CASCADE` never re-enters it, leaving the live FK at `CASCADE` and diverging from both `worktree_id` (already `SET NULL`) and the `v2.6.3` changelog's own claim that `session_id` is informational `SET NULL`. The fix adds a standalone `confdeltype`-guarded `DO` block (mirroring the `session_worktrees` defang) that flips `session_id_fkey` `CASCADE → SET NULL` independently of the re-key gate; it is idempotent — fires only while the FK is still `'c'`, a no-op on a fresh deploy (already `'n'`) and on every re-run. The live DB was converged by hand with the identical statements, so `applySchema` and the hand-applied state match (`\d agent_sessions` now shows `session_id ... ON DELETE SET NULL`). Also bundles a CLAUDE.md doc-sync (committed separately): per-session SSE (P1.5-a) and the `(chat_id, agent)` re-key reflected in the engineering notes, the stale root `AGENTS.md` navigation pointer dropped, and new conventions for `data/AGENTS.md` parsing and the `data/skills/<vendor>/` layout.
+
+## v2.6.3-chatkey-and-skills — 2026-05-31
+
+Three threads. **agent_sessions re-keyed to `(chat_id, agent)` (P1.5-b):** the tab (a chat) is now the agent-context unit, so two opencode tabs in one BooCode session are two independent contexts that share one worktree. `chat_id` is threaded end-to-end — `tasks.chat_id` added, stamped by the coder message + skills routes from the frontend tab, read by `runOpenCodeServerTask` which falls back to resolve-or-create a chat for session-less creators (arena/MCP/new_task/generic `/api/tasks`) so `ensureSession` never receives a degenerate `(null, agent)` key. A new first-class `worktrees` table (one-per-session, survives session delete via `session_id ON DELETE SET NULL`) supersedes `session_worktrees`, which is defanged (CASCADE dropped, not yet removed); `agent_sessions.chat_id` CASCADEs from `chats` (closing a tab ends its context) while `worktree_id`/`session_id` are informational `SET NULL`. The migration is idempotent with a backfill-verify gate; the live re-key was applied against an empty table after the 35-chat test session `20d28876` was deleted (backed up first). This corrects and supersedes an earlier draft that wrongly keyed on `(worktree_id, agent)`; the delete-guard from `v2.6.2-delete-guard-and-sse` is repointed here from `session_worktrees` to `worktrees` (`worktree_path`→`path`). **dcp-strip cross-chunk fix:** the `<dcp-message-id>` tag streams split across SSE deltas, which the per-chunk strip from `v2.6.1-phase1-opencode` missed — a stateful `makeDcpStreamStripper` at the dispatcher boundary holds back partial-tag tails so neither live frames nor persisted content carry the tag (11 unit tests). **Agent-judgment skills:** `committing-changes` (segment by concern, stage explicitly, present-and-stop, never push) and `using-worktrees` (the when-to-isolate heuristic, autonomous-when-clear vs committing's command-gate) land in `data/skills/boocode/` with eval.yamls, plus a parser-safe `data/AGENTS.md` preamble pointing at both.
+
+## v2.6.2-delete-guard-and-sse — 2026-05-30
+
+Two coder-side batches under one tag. **Session-delete work-loss guard:** deleting a BooChat session CASCADE-wipes its `session_worktrees` row, which would silently orphan uncommitted/unpushed/unmerged work — so the server's `DELETE /api/sessions/:id` now gates before the delete. It reads `session_worktrees` from the shared DB first (no row → chat-only session → delete immediately, zero round-trip), and for worktree-backed sessions calls a new BooCoder endpoint (`/worktree-risk`) that runs git on the host, since the container can't see `/tmp/booworktrees` — only the host systemd service can. `checkWorktreeWorkAtRisk` reports dirty/unpushed/unmerged via the audited `hostExec`+`shellEscape` path, default branch detected from `refs/remotes/origin/HEAD` (never the worktree's own branch, never hardcoded); any at-risk worktree returns 409 with per-worktree `RiskReport[]`, `force=true` bypasses, and the check is fail-closed (BooCoder unreachable also blocks — force still escapes). The sidebar renders a block dialog distinguishing work-at-risk (Commit/Stash/Force; stash uses `-u` and re-blocks on remaining commits) from couldn't-verify (Cancel/Force), and Commit never auto-commits. A follow-up fix gates the `unpushed` arm behind an actual upstream (`atRisk = dirty || unmerged > 0 || (hasUpstream && unpushed > 0)`) so the no-upstream `session-<id>` branches stop flagging every pristine worktree-backed session — no protection lost, since real local work always also surfaces as `unmerged > 0`. **Per-session SSE (P1.5-a):** replaces the single global SSE loop scoped to the most-recent worktree directory — the known limit flagged in `v2.6.1-phase1-opencode` — with one `event.subscribe({directory})` per live opencode session, so sessions in different worktrees stream concurrently instead of the second silently dropping the first's events. Each session owns an `AbortController` wired into `subscribe(…, {signal})`, which also fixes a latent Phase-1 bug where switching directories left the old loop parked forever in its `for await` (zombie loops); a `sessionID` demux guard drops cross-session events so two sessions sharing a worktree (possible after P1.5-b) don't double-process deltas. The opencode SDK was confirmed to open an independent SSE connection per `subscribe()` call, so N concurrent dir-scoped streams are supported.
+
+## v2.6.1-phase1-opencode — 2026-05-30
+
+v2.6 Phase 1: opencode runs as a warm HTTP server (`apps/coder/src/services/backends/opencode-server.ts`) — one `opencode serve` per BooCoder process, one opencode session per BooCode session resumed across turns via the new `agent_sessions` table, with a single SSE read loop, reasoning dedup ported from Paseo, an inactivity watchdog, and a stale-session guard (crashed-not-resumed + a `config_hash` fingerprint over `opencode_server|<model>`, deliberately excluding the ephemeral server port so cross-restart resume survives). Builds on the `v2.6.0-phase0-foundations` schema/interface scaffold. The batch's hard-won fixes: opencode streams `session.next.*` events (not `message.part.*`), and `event.subscribe()` must pass the session's worktree `directory` or events route to the server CWD and turns come back empty; model strings must be `llama-swap/`-prefixed and present in opencode's own config, with `agent-probe` now populating `available_agents.models` via `mergeLlamaSwap` so the frontend stops sending an empty model; `session_worktrees`/`agent_sessions` FKs are `ON DELETE CASCADE` so session deletion no longer 500s. Also bundled: dcp-message-id tag stripping from opencode text output, a reopen-closed-pane control, the `[+]`/split-pane button separation, auto-name using the session's loaded model, and a `systematic-debugging` slash command. Smoke 1 verified end-to-end (two turns, session reuse, turn 2 ~9x faster). Known Phase 1 limit: one SSE stream scoped to the most-recent session's directory — concurrent opencode sessions in different worktrees collide (warns; per-session SSE is Phase 2).
+
+## v2.5.15-acp-path-guard — 2026-05-29
+
+Security fix + repo hygiene. Fixes a path-traversal in the ACP filesystem bridge (`acp-client-fs.ts`, flagged by the automated push security review): the worktree guard used an unbounded `startsWith(resolve(worktreePath))`, so a sibling path sharing the worktree as a string prefix (`<worktree>-evil/…`) escaped the scope — and `writeWorktreeTextFile` writes to disk directly (no `pending_changes` gate), so a confused/buggy ACP agent could write outside its worktree. Now uses a separator-bounded check matching `write_guard.ts` (`resolve()` + `startsWith(root + sep)` / `=== root`) via a shared `resolveInWorktree`, with a regression test covering `../` traversal and the sibling-prefix bug. Symlink-swap/`O_NOFOLLOW` hardening was intentionally skipped — consistent with `write_guard`'s no-realpath stance, and the agent already runs with host FS access so this is a containment guard, not a trust boundary. Separately, stops tracking the live `data/coder-providers.json` (it's runtime config the UI reads *and writes* on provider toggles, which churned `git status`) — it's now gitignored with a tracked `data/coder-providers.example.json` reference; the loader falls back to built-ins-only when the live file is absent. The provider-type duplication (coder ↔ web) stays guarded by the existing text-identity `provider-types-parity.test.ts` — a shared package was considered and declined (drift is already prevented; not worth the Docker/build-order risk at solo scale).
+
+## v2.5.14-claude-md — 2026-05-29
+
+Docs-only — CLAUDE.md session-learnings update, no code. Adds gotchas surfaced while shipping the v2.3 provider-lifecycle batch: the host `boocoder.service` keeps running the old process after `pnpm -C apps/coder build` (stale-process tell = new routes 404 while old routes 200, restart don't re-debug); the `boocode` container `build: .` deploys the working tree, so web edits are live on the Vite dev server but not production until `docker compose up --build -d boocode`; `PATCH /api/providers/config` replaces a provider's override wholesale (send `{...existing, enabled}` or a custom ACP entry's command is wiped) and `data/coder-providers.json` is live config not to be committed as code; external agents dispatch one-shot with no context/token tracking (only native `boocode` tracks ctx; OpenCode-as-server is the unshipped `v2-6-persistent-agent-sessions` plan); the `ui/` primitive inventory with `button role=switch` / Dialog fallbacks for the absent switch/sheet; and the mobile Dialog-with-list scroll-containment recipe. Also backfills previously-uncommitted doc bullets for the `v2.5.7`–`v2.5.11` coder work (provider-type parity test, async ACP command discovery, AgentComposerBar `installed` filter, provider-registry path disambiguation).
+
+## v2.5.13-provider-lifecycle-phase5 — 2026-05-29
+
+Closeout of the v2.3 provider-lifecycle batch — the web UI (Phase 5) plus docs (Phase 6). Provider management moved into **Settings → Providers**: a tab listing every registered provider with a status badge (Available / Disabled / Not installed / Error / Loading), an enable/disable toggle, a per-provider refresh, and a plaintext diagnostic; toggling sends the provider's *full* override (preserving a custom ACP entry's command under the wholesale-replace PATCH merge) then refetches the snapshot. The composer's provider picker now filters to `enabled && (status === 'ready' || 'loading')`, so disabled and unavailable providers drop out of the picker and are managed only in settings (native `boocode` always shows). A curated ACP catalog (`apps/web/src/data/acp-provider-catalog.ts`) + `AddProviderModal` register custom providers via `PATCH /api/providers/config` then a subset refresh, and the web client gained `getProvidersConfig` / `patchProvidersConfig` / `refreshProviders` / `getProviderDiagnostic`. Two mobile fixes ship alongside: the Settings pane is now reachable on phones (opening it pushes `?pane=` atomically so the mobile URL-sync effect keeps it active instead of snapping back to the chat pane), and the Add-provider modal caps to the viewport with a single `overscroll-contain` scroll region so the list scrolls instead of dragging the whole modal. This completes the arc begun in `v2.5.4-provider-lifecycle-phase1` (config-backed registry over the built-ins) → `v2.5.5-provider-lifecycle-phase2` (loading/unavailable snapshot lifecycle + tier-2 probe TTL gate) → `v2.5.6-provider-lifecycle-phase3` (generic `resolveLaunchSpec` ACP dispatch) → `v2.5.12-provider-lifecycle-phase4` (config GET/PATCH, subset refresh, diagnostic HTTP API). Docs landed in `BOOCODER.md` (config file, refresh contract, enable/disable, custom ACP, the honest subset-refresh known limitation) and `docs/DEFERRED-WORK.md` §2 is marked addressed; the remaining Tier-2 follow-ups (WS `provider_snapshot_updated` frame, `available_agents.enabled` column, shared types package, MCP provider tools) stay deferred.
+
+## v2.5.12-provider-lifecycle-phase4 — 2026-05-29
+
+Phase 4 of the v2.3 provider-lifecycle batch (`openspec/changes/v2-3-provider-lifecycle/design.md` §6): the HTTP API to read, patch, refresh, and diagnose providers. `routes/providers.ts` gains `GET /api/providers/config` (the raw loaded `CoderProvidersFile`), `PATCH /api/providers/config` (a partial providers map — an id's override object is replaced wholesale, a `null` value deletes it), an optional `{ providers?: string[] }` body on `POST /api/providers/refresh` (the `refreshed` count reflects the requested subset; the force probe itself still covers all installed providers, since per-provider force is a snapshot-internal change left to a later phase), and `GET /api/providers/:id/diagnostic` returning JSON `{ diagnostic: string }` — a read-only report (resolved def, install_path, last_probed_at, enabled, `which` availability, last cached probe error) with no probe spawn. PATCH correctness is the whole story: the order is validate→save→reload→clear, a malformed body or an invalid merged config returns 422 without writing the file, and a `save()` failure returns 500 without reloading the registry or clearing the snapshot cache, so on-disk and in-memory state can never diverge. New pure `mergeProviderConfigPatch` + `ProviderConfigPatchSchema` in `provider-config.ts`, a read-only `peekSnapshotEntry` cache accessor (source of the diagnostic's last-error — no probe/cache logic change), and a new `provider-diagnostic.ts` formatter. The web client gains `api.coder.getProvidersConfig` / `patchProvidersConfig` / `refreshProviders(providers?)` / `getProviderDiagnostic`, with mirrored `ProviderOverride` / `CoderProvidersFile` / `ProviderConfigPatch` types; the existing `/api/coder/*` proxy blanket-forwards the new routes with no change. +28 tests (134 coder total: pure merge/validate, the diagnostic formatter, and `app.inject` route tests proving the 422-no-write and save-fail-no-divergence guards). The diagnostic returns JSON rather than the §8 plaintext so it flows through the JSON `request` client helper (reconciling design §6.4's `{ diagnostic }` with §8's string report). No UI (Phase 5). Builds on `v2.5.6-provider-lifecycle-phase3`.
+
+## v2.5.11-claude-skill-discovery — 2026-05-29
+
+Surface Claude Code's real enabled commands + plugin skills in the coder slash menu, with icons separating commands from plugin skills. New `claude-command-discovery.ts` reads (user-global scope) `~/.claude/commands/*.md` plus every enabled plugin in `~/.claude/settings.json:enabledPlugins` — each plugin's user-scope install path contributes `skills/<name>/SKILL.md` (kind `skill`) and `commands/*.md` (kind `command`), parsed from frontmatter, bare names, deduped. The snapshot's claude branch discovers these **live** (claude is PTY, no ACP probe; the snapshot cache rate-limits the fs reads). The `/` menu now renders up to three icon'd groups: **`<agent> commands`** (Terminal), **`<agent> skills`** (Puzzle — claude's plugin skills / opencode is all commands), and **BooCoder skills** (Sparkles), via a new optional `icon` on `SlashCommandGroup`. `AgentCommand` gains a `kind` field, added identically to the coder and web copies (the `provider-types-parity` test enforces it); `mergeCommandsByName` is now generic so it preserves the tag. Invocation is unchanged — picking a claude command/skill sends `/name` to claude (PTY), which executes it. Project-local plugins + `<cwd>/.claude/commands` deferred. BooChat unaffected (flat skills). Smoke-test the claude skill slash-execution on the host.
+
+## v2.5.10-opencode-live-commands — 2026-05-29
+
+Surface opencode's real (live ACP) command set in the coder slash menu without needing a dispatch. Two fixes: (1) the cold ACP probe (`acp-probe.ts`) captured `available_commands` but read `probedCommands` synchronously right after `newSession` — racing opencode's async `available_commands_update` notification, so it captured **zero** and only the 7-item static manifest showed. The probe now waits briefly (poll up to 3s for the first batch + a 300ms settle, capped under the 30s probe timeout) so the commands are actually captured. (2) Captured commands are persisted to a new `available_agents.commands` JSONB column and served (merged with the manifest) on the tier-2-probe-skip path, so the agent's discovered commands survive once the model list is warm and show without a dispatch. Boot warms this via the `force: true` startup snapshot. apps/coder only (probe + schema + snapshot). Caveat: depends on opencode emitting `available_commands_update` on session creation rather than only after a prompt — to be confirmed on the host. Claude (PTY) disk/plugin discovery deferred.
+
+## v2.5.9-agent-slash-commands — 2026-05-29
+
+Segmented per-agent slash menu in the coder pane, plus cross-agent skills. The `/` menu now shows two labeled groups — **the active agent's commands first** (opencode/claude/qwen manifest + live ACP `available_commands`), **BooCoder skills second** — instead of always showing BooCoder's skills regardless of provider. `SlashCommandPicker` gains an opt-in `groups` prop (the flat `items` path is unchanged, so **BooChat's menu is byte-identical** — parity verified: no BooChat caller passes the grouped prop, and the skills lookup / invocation routing are untouched); `ChatInput` takes `slashGroups`; `CoderPane` builds the groups from the selected provider's commands + skills. Skills now **run under the selected agent**: the coder `skill_invoke` route accepts a `provider` and, when external, injects the server-side skill body into a dispatched task (instead of native inference) — so a skill like brainstorming executes through opencode/claude with the body kept server-side, mirroring the messages-route external dispatch. Also folds in the earlier initial-chat fix: invoking a skill on the landing chat now runs the same create-chat → assign-to-pane → invoke transition as a text send (`handleLandingSkill`) rather than invoking invisibly without a pane transition (the blank-screen repro). Web tsc + coder build clean.
+
+## v2.5.8-mobile-composer-row — 2026-05-29
+
+Mobile fix for the `AgentComposerBar`: the refresh button was wrapping to a second line. Root cause was layout order, not width — the status dot carried `ml-auto` (pinned to the far-right edge) and the refresh button followed it in DOM order, so it overflowed and wrapped. The dot + refresh are now one right-aligned (`ml-auto`) unit, keeping the refresh on the top line. Additionally, `CompactPicker` gained an `iconOnly` option and the Mode (permission) picker now renders icon-only on mobile (shield + chevron, no "Bypass"/"Plan" text label; `aria-label`/`title` and the tap-to-open list still convey the value) to free row width. Desktop is unchanged (full labels). Web-only change.
+
+## v2.5.7-claude-models-and-picker-fix — 2026-05-29
+
+Two provider-layer changes. **(1) Fix the empty provider picker** — a regression from `v2.5.5` (Phase 2): on a cache miss `getProviderSnapshot` returned synchronous `installed:false` `loading` entries, which `AgentComposerBar` filters out (`e.installed && e.status !== 'error'`); with the client-side poll deferred to Phase 5, a single fetch landed on `loading` forever and no providers appeared. `getProviderSnapshot` now awaits the build and returns terminal entries (the sync `loading` return is deferred until Phase 5 ships the poll); builds stay fast via the tier-2 cold-probe skip. **(2) Claude models** — the list was a hardcoded 2-entry static list (Opus 4 / Sonnet 4, May 2025), and the v2.3 config schema's `models`/`additionalModels` were parsed but never wired. `buildResolvedRegistry` now carries config `models` (replace) + `additionalModels` (merge) onto `ResolvedProviderDef`, and `provider-snapshot` applies them to every ready model list — so `/data/coder-providers.json` can add or replace any provider's models with no code change. Claude `staticModels` bumped to `opus`/`sonnet`/`haiku` latest-aliases plus pinned `claude-opus-4-8` / `claude-sonnet-4-6` / `claude-haiku-4-5-20251001` (passed verbatim to `claude --model`; the CLI accepts both aliases and pinned full names). +2 unit tests (109 total). Builds on `v2.5.6-provider-lifecycle-phase3`.
+
+## v2.5.6-provider-lifecycle-phase3 — 2026-05-29
+
+Phase 3 of the v2.3 provider-lifecycle batch (`openspec/changes/v2-3-provider-lifecycle/design.md` §5): generic ACP dispatch. `acp-spawn.ts` gains `resolveLaunchSpec(resolved, installPath)` — it consults the resolved registry's `launchCommand` (a config override or a custom-ACP entry's command) first, falling back to the kept `resolveAcpSpawnArgs` switch for built-ins. `acp-dispatch.ts` now spawns `spec.binary`/`spec.args` with `env: { ...process.env, ...spec.env }` instead of the hardcoded per-name argv, and `dispatcher.ts` loads the resolved def by `task.agent` and passes it through. This lets config-defined custom ACP providers dispatch with no new switch case. Built-in dispatch (claude/opencode/goose/qwen) is **byte-identical** to pre-v2.3 — proven by a regression test asserting opencode→`['acp']`, goose→`['acp']`, qwen→`['--acp']`, binary=`installPath ?? id`, and empty config env → plain `process.env`. One deliberate deviation from the spec's literal `!installPath → null`: the `installPath ?? id` fallback is preserved so a missing install path still spawns the bare agent name as before. `setSessionMode`/permission/streaming and the dispatcher poll/NOTIFY/running-guard are untouched. 7 new `acp-spawn.test.ts` cases. No routes/UI (Phase 4+). Builds on `v2.5.5-provider-lifecycle-phase2`.
+
+## v2.5.5-provider-lifecycle-phase2 — 2026-05-29
+
+Phase 2 of the v2.3 provider-lifecycle batch (`openspec/changes/v2-3-provider-lifecycle/design.md` §4). `provider-snapshot.ts` stops returning `null` for uninstalled/disabled providers — it now emits one entry per registered provider with a lifecycle status (`loading | ready | unavailable | error`), an `enabled` flag, and a two-tier probe. Tier-1 is a fast `which`-style availability check (`command-availability.ts`, `execFile`/no-shell); tier-2 — the 5–30s cold ACP probe — is now SKIPPED unless forced (`POST /refresh`), the `available_agents.last_probed_at` row is older than `PROVIDER_PROBE_TTL_MS` (24h default), or the DB model list is empty, which kills snapshot latency on warm reads. A cache miss returns `status:'loading'` synchronously while the build settles in the background (client polling is deferred to Phase 5). `ProviderSnapshotStatus`/`ProviderSnapshotEntry` regained `loading`/`unavailable` and gained `enabled`, `description?`, `fetchedAt?` in both the coder and web copies, guarded by a runtime parity test (`provider-types-parity.test.ts`, mirroring the `ws-frames.test.ts` convention) that fails on any field drift — a compile-time cross-project assignability check was attempted first but blocked by TS6307 (web is a composite tsconfig project). Also tracks the previously-gitignored `data/coder-providers.json` seed via a `.gitignore` exception, completing the Phase 1 config file. No dispatch/route/UI changes (Phase 3+); AgentComposerBar filtering unchanged. Builds on `v2.5.4-provider-lifecycle-phase1`.
+
+## v2.5.4-provider-lifecycle-phase1 — 2026-05-29
+
+Phase 1 of the v2.3 provider-lifecycle batch (`openspec/changes/v2-3-provider-lifecycle/design.md` §2–3): a config-backed provider layer merged over the hardcoded built-ins, with no runtime change when no config file exists. Adds `CODER_PROVIDERS_PATH` (default `/data/coder-providers.json`); `provider-config.ts` (Zod `ProviderOverride`/`CoderProvidersFile` schemas + a loader that never throws at startup — a missing file, invalid JSON, or schema mismatch all fall back to built-ins-only — plus `save` for the Phase 4 PATCH route); and `provider-config-registry.ts` (`ResolvedProviderDef` + `buildResolvedRegistry` merge: built-in overrides, custom `extends:'acp'` entries requiring label+command, `boocode` always enabled, plus a module singleton). `agent-probe.ts` now iterates the resolved registry instead of the hardcoded list — custom ACP entries resolve their binary from `command[0]` via `execFile` (no shell), disabled providers skip probing without losing their row, and `enabled` is read from memory only (no DB column this phase). Six unit tests, including a regression proving an empty config yields exactly the built-ins. No snapshot/dispatch/route/UI changes (Phase 2+). The `data/coder-providers.json` seed exists on disk but is gitignored (`data/*`). Lands on top of `v2.5.3-remove-cursor-copilot`.
+
+## v2.5.3-remove-cursor-copilot — 2026-05-29
+
+Retire the cursor and copilot providers from BooCoder entirely. Removes their `acp-spawn` argv cases, `provider-manifest` mode blocks + manifest keys, `provider-commands` command maps, the `provider-snapshot` cursor model-CLI branch (and the now-orphaned `exec`/`promisify` imports), and the `agent-probe` copilot ACP-detect branch; deletes the dead `cursor-models.ts` module and its test. The `PROVIDERS` registry array already lacked both entries, so only the doc comment needed correcting. Built-ins unchanged: claude, opencode, goose, qwen, native boocode. Standalone cleanup; pairs with `v2.5.4-provider-lifecycle-phase1` which builds on it.
+
+## v2.5.2-coder-ux-fixes — 2026-05-29
+
+Working-tree checkpoint bundling this session's fixes with in-progress coder UI work. This session: the BooCoder dispatcher now reacts to new tasks immediately via a Postgres `LISTEN/NOTIFY` (`tasks_new`) AFTER INSERT trigger, with the poll loop kept at 2s as a missed-notification fallback (`dispatcher.ts`, `apps/coder/src/schema.sql`); the mobile nav drawer no longer sticks open after returning to a backgrounded tab — `useViewport` re-syncs on `pageshow`/`visibilitychange`/`resize`/`orientationchange` (iOS reported a stale width on bfcache restore, leaving `isMobile=false`); assistant reasoning renders as a collapsible "Thinking" block in `MessageBubble`, surfacing ACP `agent_thought_chunk` from opencode/goose/qwen and native `reasoning_parts`; paste-to-chip inserts pasted text verbatim instead of wrapping it in a code fence; and a "New file from pasted text" affordance in the RightRail browser queues a `pending_changes` create through the new `POST /api/sessions/:id/pending/create` endpoint, paired with a fix repointing the DiffPanel's dead approve/reject calls to the real `/api/pending/:id/apply` and `/reject` routes. Also carried in the tree but not authored this session: the CoderPane `ChatInput` migration and `AgentComposerBar` refinements, plus backend tweaks to `auto_name`, inference `tool-phase`/`turn`, `secret_guard`, and `provider-registry`. Ships the `v2-6-persistent-agent-sessions` openspec proposal/design/tasks (free agent-switching with per-agent memory, opencode-as-server) as planning docs only — the feature is unimplemented and reserves the `v2.6.0` tag for it. Build green across server/coder/web; server suite 531 passing. (CHANGELOG note: the v2.3–v2.5.1 entries were never backfilled and remain absent above.)
+
 ## v2.2.2-xml-placeholder-reject — 2026-05-26
 
 Reject placeholder XML tool args at parse time in `extractToolCallBlocks` (`xml-parser.ts`). Drops calls when any string arg is `...`, empty/whitespace, `<path>`, `<file>`, `placeholder`, or angle-bracket sentinels; appends the raw XML block to flushed prose instead of silently deleting it. Fixes qwen3.6 answer-then-spurious-tools tail that caused duplicate assistant rows (full answer + failed `xml_call_*` tools + regenerated answer). Four new tests in `xml-parser.test.ts`. Known nit: rejection logs via `console.debug` instead of pino — filed in `docs/DEFERRED-WORK.md` §6 for a later cleanup.

CLAUDE.md

@@ -2,11 +2,11 @@
 
 This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
 
-**Cursor agents:** start with `AGENTS.md` (navigation) and `docs/ARCHITECTURE.md` (diagram). This file is the deep engineering reference.
+**Cursor agents:** start with `docs/ARCHITECTURE.md` (diagram); this file is the deep engineering reference. `data/AGENTS.md` is the agent *registry*, not navigation (the root navigation `AGENTS.md` was removed).
 
 ## What is BooCode
 
-Self-hosted single-user developer chat app. AI assistant with read-only file tools (view_file, list_dir, grep, find_files) running against a local llama-swap inference server. Sessions organized by project, with a multi-pane workspace (chat + file browser side by side).
+Self-hosted single-user developer chat app. AI assistant with read-only file tools (view_file, list_dir, grep, find_files) against a local llama-swap inference server. Sessions organized by project, multi-pane workspace (chat + file browser side by side).
 
 Plus `apps/booterm` (second container, port 9501, bookworm-slim+glibc): Fastify + node-pty + tmux. Browser terminal panes WS to `/ws/term/sessions/:sid/panes/:pid`; per-session tmux session `bc-<sid>`, per-pane window `term-<pid>`. Shells drop privs to samkintop via `gosu` in `tmux.conf` default-command.
 
@@ -23,90 +23,33 @@ pnpm -C apps/server build  # server only (tsc + copy schema.sql)
 pnpm -C apps/web build     # web only (vite)
 
 # Type checking (no emit)
-npx tsc --noEmit                              # project references (root)
-npx tsc -p apps/web/tsconfig.app.json --noEmit  # web app specifically
-
-# IMPORTANT: root tsc --noEmit uses project references and can miss errors
-# that the per-app tsconfig catches. Always verify with the per-app command
-# when editing web code. The server build (pnpm -C apps/server build) is
-# authoritative for server code.
+# Per-app is authoritative. There is NO root tsconfig.json (only tsconfig.base.json),
+# so a bare `npx tsc --noEmit` at root compiles nothing.
+npx tsc -p apps/web/tsconfig.app.json --noEmit   # web (authoritative)
+pnpm -C apps/server build                        # server typecheck (tsc + copy schema)
+pnpm -C apps/coder build                         # coder typecheck
+pnpm -C apps/booterm typecheck                   # booterm typecheck
 
 # Production
 docker compose build --no-cache boocode && docker compose up -d
 ```
 
-Tests: `pnpm -C apps/server test` runs the vitest suite. No test harness on `apps/web` (adding it requires installing vitest as a new devDep). Vitest pinned to `^3` because Vite 5 / vitest 4 are incompatible. No linters configured. Vitest include glob is `src/**/__tests__/**/*.test.ts` (see `apps/server/vitest.config.ts`) — tests outside `src/**/__tests__/` silently won't run; match the per-domain convention (`apps/server/src/services/__tests__/foo.test.ts`).
+Tests: `pnpm -C apps/server test` (vitest); `apps/coder` has its own suite — `pnpm -C apps/coder test` (`globals:false`, so import `describe`/`it`/`expect` from `vitest`). No `apps/web` test harness, no linters. Vitest pinned to `^3` (Vite 5 / vitest 4 incompatible). Include glob is `src/**/__tests__/**/*.test.ts` — tests outside it silently won't run. Extract pure helpers to unit-test (`backends/turn-guard.ts`, `lifecycle-decisions.ts` are the pattern).
 
 ## Architecture
 
-**Monorepo**: pnpm workspaces with `apps/server` (Fastify + postgres), `apps/web` (React + Vite), and `apps/booterm` (Fastify + node-pty + tmux).
+**Monorepo**: pnpm workspaces with `apps/server` (Fastify + postgres), `apps/web` (React + Vite), `apps/booterm` (Fastify + node-pty + tmux), `apps/coder` (BooCoder, host service), `packages/contracts` (`@boocode/contracts`, cross-app wire-contract SSOT — builds FIRST).
 
-### Server (`apps/server/src/`)
+### Per-app deep references
 
-- **Fastify** with `@fastify/websocket` and `@fastify/static` (serves built frontend)
-- **postgres** (porsager/postgres) with tagged-template SQL — no ORM. Schema in `schema.sql`, applied on startup. LSP may false-positive on `sql<Type[]>\`...\`` generics; CLI `tsc` / `pnpm build` is authoritative.
-- **Zod** for request validation and config parsing.
+Detailed engineering notes live in per-app `CLAUDE.md` files, **auto-loaded when you read/edit files in that subtree** (and worth opening before non-trivial work there):
 
-Key services:
-- **`services/inference/`** — Public surface re-exported via `inference/index.ts`; callers import from `./services/inference/index.js` explicitly (NodeNext doesn't honor directory-index resolution). Layout: `turn.ts` (runAssistantTurn / runInference / createInferenceRunner; exports `InferenceFrame`, `InferenceContext`, `TurnArgs`, `StreamResult`, `MAX_STEPS`), `stream-phase.ts` (streamCompletion as a v1.13.1-A AI SDK adapter + executeStreamPhase), `provider.ts` (`upstreamModel(baseURL, modelId)` wrapping `createOpenAICompatible` against llama-swap), `tool-phase.ts` (executeToolPhase → returns `ToolPhaseResult`; no longer recurses into runAssistantTurn — v1.14.0 converted the recursion to an explicit while loop in turn.ts), `sentinel-summaries.ts` (runCapHitSummary + runDoomLoopSummary + runStepCapSummary + their sentinel inserters), `error-handler.ts` (handleAbortOrError, finalizeCompletion), `payload.ts` (buildMessagesPayload, loadContext, maybeFlagForCompaction, `OpenAiMessage`), `sentinels.ts` (`detectDoomLoop`, `DOOM_LOOP_THRESHOLD`, sentinel predicates), `budget.ts` (resolveToolBudget), `xml-parser.ts` (qwen3.6 XML tool-call fallback — KEEP, AI SDK doesn't handle inline-XML tool calls), `parts.ts` (parts-table write helpers: `partsFromAssistantMessage`, `partsFromToolMessage`, `insertParts` — v1.13.20 made parts the sole source of truth), `prune.ts` (v1.13.4 two-tier compaction; `selectPruneTargets` is the pure decision helper), `types.ts` (`StreamPhaseState`, `DB_FLUSH_INTERVAL_MS`). **`TurnArgs`** is the per-turn state envelope populated from loop locals each iteration; reset in `runInference` at user-message boundary. The outer loop in `runAssistantTurn` (v1.14.0) runs `while (stepNumber < effectiveCap)` where `effectiveCap = Math.min(agent.steps ?? Infinity, MAX_STEPS=200)`. Per-agent `steps:` field in AGENTS.md frontmatter. `steps: 0` means text-only (no tool execution). Step-cap hit writes a `cap_hit` sentinel so `CapHitSentinel.tsx` renders it.
-- **AI SDK v6 streamCompletion adapter** (v1.13.1-A; `services/inference/stream-phase.ts`). `streamText` is the underlying call; the BooCode layer above (executeStreamPhase, finalize, dual-write) is shape-preserved via an adapter. Five gotchas the LSP/test suite won't catch:
-  - **Abort signals are swallowed.** `streamText`'s `fullStream` iterator exits cleanly when `abortSignal` fires — no throw. Post-iteration `if (signal?.aborted) throw <AbortError>` is required; without it the row finalizes as `complete` instead of `cancelled`. Comment in stream-phase.ts pins this; don't refactor it away.
-  - **Usage lands only at stream end** via `await result.usage` (`inputTokens` / `outputTokens` v6 names → mapped to `promptTokens` / `completionTokens` for the existing onUsage callback). Mid-stream live tok/s is gone vs v1.12.2; ChatThroughput shows a single value at stream end.
-  - **Tools have NO `execute` field.** BooCode dispatches tools in tool-phase.ts, not the AI SDK loop. Only `description` + `inputSchema: jsonSchema(parameters)` — surfacing tool-call parts via `fullStream` and stopping is what we want.
-  - **`includeUsage: true` MUST be set on `createOpenAICompatible`** in `services/inference/provider.ts`. The adapter defaults it false, omitting `stream_options.include_usage` from the request body; llama-swap then never emits the usage block and `result.usage.inputTokens/outputTokens` resolve to `undefined`. Latent regression from v1.13.1-A through v1.13.7 — every assistant row in that window has `tokens_used`/`ctx_used` NULL. Don't remove this flag during refactor.
-  - **Tool-call-only turns may emit a leading `\n` text-delta** as the assistant content. `MessageList.flatten`'s `hasText` and `MessageBubble`'s `hasContent` both `.trim()` before the length check — otherwise whitespace-only content renders an empty bubble + ActionRow between every tool call (v1.13.7 fix). `payload.ts:buildMessagesPayload` also skips `status='failed'` AND complete-but-empty (no content, no tool_calls) assistant rows to avoid "Cannot have 2 or more assistant messages at the end of the list" upstream rejections after cap-hit + Continue.
-- **AI SDK ModelMessage conversion** (`toModelMessages` in stream-phase.ts). Tool messages need a `toolName` for `ToolResultPart` — BooCode's OpenAI-shape history doesn't carry it, so a forward-scan builds a `tool_call_id → toolName` map from prior assistant `tool_calls`. Tool outputs wrapped as `{ type: 'json' | 'text', value }` matching the v6 `ToolResultOutput` union. Assistant messages with reasoning emit a `ReasoningPart` first in the content array (v1.13.1-C).
-- **`experimental_repairToolCall`** (v1.13.3) wired into `streamText` to keep the stream alive when qwen3.6 emits malformed tool args. Pass-through implementation — logs the bad call and returns it unmodified; `executeToolPhase`'s existing zod-reject error path routes it to the model on the next turn.
-- **`chat_status` frame shape** (published via `broker.publishUser`) — `status: 'streaming' | 'tool_running' | 'waiting_for_input' | 'idle' | 'error'` (widened from `working|idle|error` in v1.12.1). Frontend `useChatStatus` derives `idle_warm` (<30s since idle) vs `idle_cold`. `ChatThroughput` renders inline beside `StatusDot` only when streaming or tool_running, fed by 500ms-throttled `'usage'` WS frames (`completion_tokens` + `ctx_used` + `ctx_max`). The `POST /api/chats/:id/discard_stale` endpoint exists to mark a stuck-streaming row as `failed` when the frontend's 60s no-token-activity timer (`ChatPane` content-length watcher) gives up.
-- **Boot-time stale-streaming sweep** in `apps/server/src/index.ts` after `applySchema()`: any `messages.status='streaming'` older than 5 minutes flips to `'failed'`. Logs only on non-zero count. Recovers from container restart while inference was mid-stream (v1.12.1).
-- **Periodic 60s sweeper** in `apps/server/src/index.ts` (v1.13.3 + v1.13.5). Same `setInterval` runs `sweepStaleStreaming` (marks `messages.status='streaming'` older than 5 min as `failed`, publishes `chat_status='idle'` so the UI dot drops) and `cleanupTruncations` (TTL + orphan reap of tmpfs truncation files). `app.addHook('onClose')` clears the timer. No-op when nothing to reap.
-- **`services/broker.ts`** — In-memory pub/sub with two channel types: per-session (message streaming) and per-user (sidebar updates). No persistence; clients reconnect on restart. v1.13.11: every WS publish goes through `broker.publishFrame(sessionId, frame)` or `broker.publishUserFrame(user, frame)` — both Zod-validate against `WsFrameSchema` (`types/ws-frames.ts`) and fail-closed (log + drop). `ctx.publish` / `ctx.publishUser` in inference + auto_name route through the index.ts adapter that calls publishFrame internally. The schema is duplicated byte-identical at `apps/web/src/api/ws-frames.ts`; a `ws-frames.test.ts` case enforces parity. Don't add new raw `broker.publish()` / `publishUser()` calls.
-- **`services/tools.ts`** — Tool registry (`ALL_TOOLS`, `READ_ONLY_TOOL_NAMES`, `TOOLS_BY_NAME`). Filesystem tools (view_file/list_dir/grep/find_files) go through three guard layers: `path_guard.ts` (workspace scope), `secret_guard.ts` (filename deny list), `url_guard.ts` (SSRF/private-IP block for web_fetch). v1.11.8+ web tools (`web_search`, `web_fetch`) are opt-in per chat via `session.web_search_enabled` (resolved with `project.default_web_search_enabled` fallback) and filtered out of the LLM's tool schema when false. v1.13.5 truncation: when a tool slice cuts content, `services/truncate.ts` stashes the full text on tmpfs at `BOOCODE_TRUNCATION_DIR` (default `/tmp/boocode-truncations`, 0o700) keyed by an opaque `tr_<12 base32 chars>` id, and the `view_truncated_output(id)` tool retrieves it. 5MB cap (matches `view_file`'s `MAX_FILE_BYTES`), 7-day TTL, reaped by the periodic sweeper. Tmpfs path means container restart loses retrieval — acceptable, the model usually has moved on.
-- **`services/compaction.ts`** + **`services/model-context.ts`** — v1.11.0 anchored rolling summary (single `summary=true` assistant row per chat, supersedes itself on each compaction). Triggered when `chats.needs_compaction` is set after an inference turn exceeds `usable(ctx_max) = floor(0.85 × ctx_max)` (v1.13.9 opencode-pattern early trigger; was `ctx_max - 20k` pre-v1.13.9, which gave only 7.6% headroom at 262k and 0 budget for ≤20k contexts). **`ctx_max` comes from `model-context.getModelContext()` which fetches `${LLAMA_SWAP_URL}/upstream/<model>/props`** — NOT from `parsed.timings.n_ctx` (the stream completion's `timings` doesn't carry n_ctx; that read was dead code until v1.11.3 ripped it out). First inferences after a boocode boot may have `ctx_max=NULL` if llama-swap hasn't loaded the model yet; negative cache TTL is 60s, recovers on next turn. v1.13.6: `buildHeadPayload` embeds `reasoning_parts` as a `<reasoning>...</reasoning>` prose prefix on the assistant `content` (OpenAI wire shape has no structured reasoning field; the summarizer reads text). Standalone tag when content is empty (tool-call-only turn). `buildHeadPayload` + `OpenAiMessage` exported for test access — keep them exported.
-- **`services/system-prompt.ts`** — `buildSystemPrompt` is the string-returning shim; `buildSystemPromptWithFingerprint` is the canonical impl returning `{prompt, fingerprint, drift}`. v1.13.8 instrumentation: SHA-256 of the assembled prefix is logged per `buildMessagesPayload` call (msg `prefix-fingerprint`, level=info); a `Map<sessionId, lastHash>` observer fires `prefix-drift` (level=warn) on hash change with a field-level `changed_inputs` diff. Smoke proved the prefix is byte-stable across turns in steady-state — the originally-planned `system_prompt_cache` DB table was dropped as redundant against the v1.12.0 input-layer mtime caches (BOOCHAT.md here + AGENTS.md global+per-project in `agents.ts:safeStat`).
-- **`services/inference/budget.ts`** — tool-call budgets: `BUDGET_READ_ONLY = 30`, `BUDGET_NON_READ_ONLY = 10` (forward-looking; no write tools yet), `BUDGET_NO_AGENT = 30` (v1.13.7; was 15 — every tool in `ALL_TOOLS` is read-only today, so no-agent mode shares the read-only-agent cap). Per-agent `max_tool_calls` from AGENTS.md frontmatter overrides.
-- **`messages_with_parts` view** (v1.13.1-B; `schema.sql`). Read sites that need `tool_calls` / `tool_results` / `reasoning_parts` SELECT from this view, NOT `messages` directly. v1.13.20 dropped the legacy `messages.tool_calls` / `messages.tool_results` JSON columns; the view now reads parts-only subselects. Writes target `message_parts` exclusively via `insertParts` (or via the helpers `partsFromAssistantMessage` / `partsFromToolMessage`). The `Message` wire type still carries `tool_calls?` / `tool_results?` because the view synthesizes them from parts — frontend reads are unchanged. Shapes: `tool_calls jsonb[]`, `tool_results jsonb` single object, `reasoning_parts jsonb[]` of `{text}`. If you ever need to UPDATE a message and return its full Message shape, do a two-step UPDATE returning `id` followed by SELECT from the view — RETURNING off the bare `messages` table no longer carries the tool fields.
-- **`services/file_ops.ts`** — Shared file operation implementations used by both inference tools and HTTP routes.
-- **`services/auto_name.ts`** — Non-streaming LLM call to generate 4-word session titles after first assistant reply.
-- **`services/provider-registry.ts`** — Static registry of provider metadata (label, transport, model source). `PROVIDERS` array, `PROVIDERS_BY_NAME` map. 5 providers: boocode (native), opencode (acp), goose (pty), claude (pty), qwen (pty).
-- **`services/agent-probe.ts`** — Startup probe using direct `exec()` (not SSH). Discovers installed agents on host, their versions, ACP support, and models. Qwen models read from `~/.qwen/settings.json`. Claude models are static from the registry. Results persisted to `available_agents` table.
-- **`routes/providers.ts`** — `GET /api/providers` returns installed providers with models. Transport field reflects actual capability (checks `supports_acp` from DB, not just registry preference).
-- **Provider picker dispatch**: when `provider !== 'boocode'`, the message route creates a `tasks` row (with `session_id` set) instead of calling `inference.enqueue`. The dispatcher picks it up and dispatches via ACP or PTY using the agent's `install_path`.
+- **`apps/server/CLAUDE.md`** — inference pipeline, AI-SDK adapter gotchas, tools, compaction, broker, the `messages_with_parts` view, sidecar routing, secret guard, the `data/AGENTS.md` registry.
+- **`apps/coder/CLAUDE.md`** — BooCoder dispatch, provider registry/probe/snapshot, opencode/ACP/PTY/Claude-SDK backends, `agent_sessions` resume.
+- **`apps/web/CLAUDE.md`** — React app, hooks/event buses, font & CSS pipeline, multi-pane workspace, all UI conventions.
+- **`docs/project-discovery.md`** — full stack / tooling / command inventory across all packages (read-on-demand).
 
-Route registration: all routes registered in `index.ts` via `register*Routes(app, sql, ...)` functions. Routes are in `routes/*.ts`.
-
-### BooCoder (`apps/coder/src/`)
-
-- Write-capable coding agent. Runs as a **systemd service on the host** (`boocoder.service`), NOT in Docker. Fastify server at port 9502, connects to postgres at `127.0.0.1:5500`.
-- **Workspace dependency on `@boocode/server`**: imports `createInferenceRunner`, `createBroker`, `ALL_TOOLS`, `appendMcpTools` from the server's compiled `dist/`. apps/server's `package.json` has an `exports` map with `types` conditions for NodeNext resolution. apps/server must build FIRST.
-- Build + deploy: `pnpm -C apps/server build && pnpm -C apps/coder build && sudo systemctl restart boocoder`. Env file at `apps/coder/.env.host`. Service file at `/etc/systemd/system/boocoder.service`.
-- Agent dispatch spawns binaries directly using `install_path` from `available_agents` — no `spawn('sh', ['-c', ...])` (fails under systemd). Follows Paseo's pattern: `spawn(fullBinaryPath, argsArray, { cwd })`.
-- systemd hardening: only `NoNewPrivileges=true` is safe. `ProtectSystem`, `ProtectHome`, `PrivateTmp` all break agent dispatch (agents need full filesystem access to read configs, write to worktrees).
-- `apps/server/tsconfig.json` has `declaration: true` so `.d.ts` files exist for workspace consumers.
-- Write tools (`edit_file`, `create_file`, `delete_file`, `apply_pending`, `rewind`) queue in `pending_changes` table. Nothing hits disk until `apply_pending` is called. `write_guard.ts` validates paths (resolve + prefix-check, no realpath since files may not exist for creates).
-- Frontend: NOT a separate SPA. BooCoder is a `'coder'` pane type within BooChat's SPA (`apps/web/`). `CoderPane.tsx` in `apps/web/src/components/panes/`. API requests go through `/api/coder/*` proxy (Vite dev + Fastify production) which rewrites to the boocoder host service (`BOOCODER_URL` env var, default `http://100.114.205.53:9502`). WS connects directly to `:9502`.
-- `apps/coder/web/` is a STANDALONE fallback SPA served at `:9502` directly. The PRIMARY BooCoder frontend is the `CoderPane` in BooChat's SPA (`apps/web/src/components/panes/CoderPane.tsx`), accessible via the "Coder" pane in the workspace at `code.indifferentketchup.com`. Both exist; the pane is what Sam uses.
-
-### Frontend (`apps/web/src/`)
-
-- **React 18** + React Router v6 + **Tailwind v4** + shadcn/radix-ui primitives.
-- **Shiki** for syntax highlighting (async `codeToHtml` in `CodeBlock.tsx` and `FileViewer` in `FileBrowserPane.tsx`).
-- Path alias: `@/` maps to `src/`.
-- **Mobile interaction primitives** (post-v1.6): `useViewport` (matchMedia, breakpoints mobile <768 / tablet 768–1023 / desktop ≥1024), `useSidebarDrawer` / `useRightRailDrawer` (Context + auto-close on `useLocation().pathname` change), `useLongPress` (500ms timer, dispatches synthetic `contextmenu` on `[data-tab-id]`), `usePullToRefresh` (80px threshold, 600ms hold), `SwipeablePaneTab` (60px close, 30px vertical bail). Tap-target convention: `max-md:min-h-[44px] max-md:min-w-[44px]`. Mobile headers: `border-b px-3 sm:px-4 py-2` + `style={{ paddingTop: 'max(0.5rem, env(safe-area-inset-top))' }}`. Hamburger left, FolderTree right.
-
-Key patterns:
-- **`hooks/sessionEvents.ts`** — Module-singleton event bus (Set of listeners). Used for cross-component communication: session renames, file-open events, attachment dispatch. 9 event types in the discriminated union. When adding a new event type to the `SessionEvent` union, you must also add a case to the `applyEvent` switch in `useSidebar.ts` (even if it's a no-op `return prev`).
-- **`hooks/useSessionStream.ts`** — WebSocket per session, `applyFrame` reducer builds message list from streaming frames.
-- **`hooks/useUserEvents.ts`** — Single app-level WS to `/api/ws/user` with exponential backoff reconnect. Forwards frames onto the sessionEvents bus.
-- **`hooks/useSidebar.ts`** — Module-singleton with Set<setState> subscriber pattern; one bus subscription guarded by `globalThis.__boocode_sidebar_subscribed` for HMR safety. Every new `SessionEvent` type needs a `case` in the `applyEvent` switch (no-op `return prev` is fine).
-- **`api/client.ts`** — Centralized typed fetch wrapper. All endpoints under `api.*` namespace.
-
-Font / CSS pipeline (apps/web):
-- Tailwind v4's `@import "tailwindcss"` directive strips font URLs from subsequent CSS `@import`s — `@fontsource*` packages must be imported as JS side-effect modules in `apps/web/src/main.tsx`, not via `@import` in `globals.css`. Otherwise the woff2 files never make it to `dist/`.
-- Lightning CSS (inside `@tailwindcss/postcss` v4) collapses contiguous unicode-ranges to wildcard shorthand (`U+0000-FFFF` → `U+????`), which iOS Safari/Vivaldi mishandles (silently drops the font from those codepoints). Use explicit non-wildcard-collapsible subranges (e.g. `U+2500-259F` not `U+2500-25FF`). The `apps/web` build script greps `dist/assets/*.css` for `U+2500-259F` and fails the build if missing — preserve that guard.
-- `@font-face` blocks must live AFTER all `@import` statements (CSS spec). Earlier placement silently breaks every subsequent `@import` (this broke the 18 theme palette imports in globals.css for one session).
-- JetBrainsMono Nerd Font self-hosted in `apps/web/src/fonts/` (TTF from ryanoasis/nerd-fonts release) — needed because `@fontsource-variable/jetbrains-mono` ships subsetted woff2s that don't cover `U+2500-259F` (box drawing + block elements, used by opencode's banner). "NL" = No Ligatures (matches `font-feature-settings: "liga" 0`); "Mono" = single-cell icon width so TUI layouts don't desync.
-- xterm-addon-webgl rasterizes glyphs via Canvas2D into a GPU texture atlas. Canvas2D does NOT honor `font-display: block` — it uses whatever font is currently registered. Gate xterm initialization on `document.fonts.load(<font-name>)` resolving before calling `term.open()` (see `fontsReady` useState in `TerminalPane.tsx`). iOS Safari/Vivaldi also reclaims WebGL contexts from backgrounded tabs: keep `webgl.onContextLoss(() => webgl.dispose())` + recreate via visibilitychange. Do NOT manually dispose+recreate the addon after font load — iOS silently fails the second GL context creation and the terminal drops to DOM renderer with stale metrics.
+Cross-app contracts (WS-frame & provider-type parity, sentinels) and everything below stay here.
 
 ### Data flow for chat
 
@@ -117,71 +60,67 @@ Font / CSS pipeline (apps/web):
 5. Tool calls: inference executes tools server-side, publishes tool_call/tool_result frames, loops back to LLM
 6. Terminal states (complete/error): DB updated with final content + token counts, `session_updated` frame published on user channel
 
-### Multi-pane workspace
-
-Sessions hold 1–5 panes (chat / empty / placeholder terminal+agent). v1.12.1 moved pane state from per-device localStorage to `sessions.workspace_panes jsonb` for cross-device sync. `PATCH /api/sessions/:id/workspace` persists; `session_workspace_updated` user-channel frame broadcasts to every device watching the session. `useWorkspacePanes` debounces saves 300ms and dedups echoes by JSON string. Legacy localStorage key `boocode.workspace.panes.<sessionId>` is read once on first hydrate (one-time seed-and-delete migration when server is empty but localStorage has data); no longer written. The deprecated `session_panes` table was dropped. `validatePanes(validChatIds)` prunes panes referencing chat IDs that no longer exist (called by `useSessionChats` after the chat list fetch lands). Each chat lives in at most one pane; tab strip is per-pane and tracks `chatIds[]` + `activeChatIdx`. Tab reorder via native HTML5 drag events.
-
 ## Database
 
-PostgreSQL 16. Database name: `boochat` (renamed from `boocode` in v2.0.0-alpha; Docker service name stays `boocode_db`). Tables: `projects`, `sessions`, `chats`, `messages`, `settings`, `message_parts` (v1.13.0), `pending_changes` (v2.0.0), `tasks` (v2.0.0), `available_agents` (v2.0.0). Views: `messages_with_parts` (v1.13.1-B parts-merge read path), `tool_cost_stats` (v1.13.10 per-tool 100-call rolling window), `human_inbox` (v2.0.0 — tasks WHERE state IN blocked/failed). (`session_panes` was dropped in v1.12.1; workspace pane state lives in `sessions.workspace_panes jsonb`.) Schema applied idempotently on startup via `applySchema()`. Use `clock_timestamp()` (not `NOW()`) inside transactions. CHECK constraints in place: `projects_status_chk` ('open'|'archived'), `sessions_status_chk` (same), `chats_status_chk` (same), `messages_role_chk`, `messages_status_chk` — keep in sync with the `*_STATUSES` const arrays in `apps/server/src/types/api.ts`. The older anonymous `messages_status_check` (without 'cancelled') and `messages_role_check` (without 'system') were dropped in v1.12.1; only the `_chk` variants remain.
+PostgreSQL 16. DB name: `boochat` (Docker service stays `boocode_db`). Tables: `projects`, `sessions`, `chats`, `messages`, `settings`, `message_parts`, `pending_changes`, `tasks`, `available_agents`. Views: `messages_with_parts` (parts-merge read path), `tool_cost_stats` (per-tool 100-call rolling window), `human_inbox` (tasks WHERE state IN blocked/failed). Schema applied idempotently on startup via `applySchema()`. Use `clock_timestamp()` (not `NOW()`) inside transactions. CHECK constraints: `projects_status_chk`/`sessions_status_chk`/`chats_status_chk` ('open'|'archived'), `messages_role_chk`, `messages_status_chk` — keep in sync with the `*_STATUSES` const arrays in `apps/server/src/types/api.ts`. **Two schema files, one DB:** `apps/server/src/schema.sql` owns `sessions`/`chats`/`messages`/`message_parts`; `apps/coder/src/schema.sql` (applied by the boocoder host service) owns `agent_sessions`, `worktrees`, `pending_changes`, `available_agents` and extends `tasks` — so e.g. an `agent_sessions` FK change goes in the **coder** schema. Idempotent FK-action flips (e.g. `ON DELETE CASCADE`→`SET NULL`) guard on `pg_constraint.confdeltype` so re-runs are no-ops.
 
-Schema CHECK migration order when renaming allowed values: (1) `ALTER TABLE ... DROP CONSTRAINT IF EXISTS <system_name>` (inline `CREATE TABLE` checks get `<table>_<column>_check`), (2) `UPDATE` rows to new values, (3) wrap new constraint ADD in `DO $$ ... pg_constraint` guard — that block is the only way to get `ADD CONSTRAINT IF NOT EXISTS`.
+Schema CHECK migration order when renaming allowed values: (1) `ALTER TABLE ... DROP CONSTRAINT IF EXISTS <system_name>` (inline `CREATE TABLE` checks get `<table>_<column>_check`), (2) `UPDATE` rows to new values, (3) wrap the new constraint ADD in a `DO $$ ... pg_constraint` guard — the only way to get `ADD CONSTRAINT IF NOT EXISTS`.
 
+**`CREATE OR REPLACE VIEW` can't reorder/rename columns** (Postgres `42P16`): append a new `messages_with_parts` column at the END of the SELECT — a mid-list insert shifts an existing column → crash-loops boot. Add it to each explicit read SELECT too (`routes/messages.ts`/`chats.ts`/`ws.ts`).
+
+**A `SELECT *` view pins every column** (`2BP01`): `DROP COLUMN` on the table fails while such a view exists. `human_inbox` is `SELECT * FROM tasks` — to drop a `tasks` column, `DROP VIEW IF EXISTS human_inbox` first, drop the column(s), then recreate the view (idempotent). Bites existing DBs only; a fresh DB never had the column, so fresh-DB testing misses it.
 
 ## Environment
 
-Required: `DATABASE_URL`, `LLAMA_SWAP_URL`. Optional: `PORT` (3000), `HOST` (0.0.0.0), `PROJECT_ROOT_WHITELIST` (/opt, read-only scope for add-existing path resolution), `BOOTSTRAP_ROOT` (/opt/projects, writable scope for create-new-project bootstrap mkdir target — host must `mkdir -p /opt/projects` before container start), `DEFAULT_MODEL`, `LOG_LEVEL`, `SEARXNG_URL` (default `http://100.114.205.53:8888` — internal Tailscale Fathom; the public `search.indifferentketchup.com` is behind Authelia and unusable from server context), `BOOCODE_TOOLS` (`core` | `standard` | `all`, default `all`; v1.13.15-tools tier filter — ceiling, never expands an agent's whitelist), `MCP_CONFIG_PATH` (optional; default `/data/mcp.json` — JSON config for MCP servers matching opencode's `mcpServers` shape; file missing = no MCP).
+Required: `DATABASE_URL`, `LLAMA_SWAP_URL`. Optional: `PORT` (3000), `HOST` (0.0.0.0), `PROJECT_ROOT_WHITELIST` (/opt, read-only add-existing scope), `BOOTSTRAP_ROOT` (/opt/projects, writable bootstrap mkdir target — host must `mkdir -p` it before container start), `DEFAULT_MODEL`, `LOG_LEVEL`, `SEARXNG_URL` (default `http://100.114.205.53:8888` — internal Tailscale; the public host is behind Authelia, unusable from server context), `BOOCODE_TOOLS` (`core`|`standard`|`all`, default `all`; a ceiling, never expands an agent's whitelist), `MCP_CONFIG_PATH` (default `/data/mcp.json`, opencode `mcpServers` shape; missing = no MCP), `CONTEXT7_API_KEY` (the Context7 MCP key, referenced from `data/mcp.json` as `"{env:CONTEXT7_API_KEY}"`). `data/mcp.json` is **gitignored** but no longer holds secrets — string values support opencode-style `{env:VAR}` substitution (`mcp-config.ts:substituteEnvVars`, applied before Zod validation; unset var → `''` + warn), so real keys live in `.env`; template `data/mcp.example.json`. A config-only edit there needs only `docker compose restart boocode` (data/ is bind-mounted); changing a referenced secret edits `.env`. MCP loads at server startup with per-server graceful degradation; the coder does NOT load MCP (BooChat only).
 
-BooCoder at port 9502: `curl http://100.114.205.53:9502/api/health`. Runs as `boocoder.service` on the host (not Docker). Deploy: `pnpm -C apps/server build && pnpm -C apps/coder build && sudo systemctl restart boocoder`. Health reports tool count: `{"ok":true,"db":true,"tools":33}`.
+BooCoder at port 9502: `curl http://100.114.205.53:9502/api/health`. Runs as `boocoder.service` on the host (not Docker). Deploy: `pnpm -C packages/contracts build && pnpm -C apps/server build && pnpm -C apps/coder build && sudo systemctl restart boocoder`. Health reports tool count: `{"ok":true,"db":true,"tools":33}`.
 
-- `FAST_MODEL` (optional) — cheaper model for titles, summaries, labeling (auto_name.ts, tool-summaries.ts). Falls back to session model or DEFAULT_MODEL when unset. Set to a small model on llama-swap (e.g. `nemotron-nano-4b`) to avoid loading the 35B for 20-token calls.
-- Qwen Code dispatch: `OPENAI_BASE_URL=http://100.101.41.16:8401/v1 OPENAI_API_KEY=dummy qwen -p "<task>" --output-format stream-json`. Install: `npm install -g @qwen-code/qwen-code@latest`. Node ≥22 required on host (container stays Node 20; BooCoder dispatches via direct spawn on host). No `--yolo` flag — non-interactive mode (`-p`) runs autonomously without approval prompts. ACP bridge is HTTP daemon (not stdio); use PTY dispatch.
-- Arena (v2.0.5): `POST /api/arena {project_id, input, contestants: [{agent?, model?}]}` dispatches the same task to N models/agents in parallel. Each contestant gets its own task + worktree. `GET /api/arena/:id` for results. `POST /api/arena/:id/select/:task_id` picks winner.
+- `FAST_MODEL` (optional) — cheaper model for titles, summaries, labeling (auto_name.ts, tool-summaries.ts). Falls back to session model or DEFAULT_MODEL. Set to a small llama-swap model (e.g. `nemotron-nano-4b`) to avoid loading the 35B for 20-token calls.
+- Qwen Code dispatch: `OPENAI_BASE_URL=http://100.101.41.16:8401/v1 OPENAI_API_KEY=dummy qwen -p "<task>" --output-format stream-json`. Install: `npm install -g @qwen-code/qwen-code@latest`. Node ≥22 on host (container stays Node 20; BooCoder dispatches via direct spawn on host). No `--yolo` flag — `-p` runs autonomously without prompts. ACP bridge is an HTTP daemon (not stdio); use PTY dispatch.
+- Arena: `POST /api/arena {project_id, input, contestants: [{agent?, model?}]}` dispatches the same task to N models/agents in parallel; each contestant gets its own task + worktree. `GET /api/arena/:id` for results; `POST /api/arena/:id/select/:task_id` picks a winner.
 
 ## Workflow
 
 - Sam reviews all diffs and commits manually. Do not commit unless explicitly asked.
-- Per-batch docs live under `openspec/changes/<slug>/{proposal,tasks,design}.md`. Already-shipped batches are snapshots in `openspec/changes/archived/`. New batches follow the proposal+tasks shape; see `openspec/README.md` for the convention.
-- Tag naming: `vMAJOR.MINOR.PATCH-slug` (e.g. `v1.13.13-ws-publish`). Monotonic per minor — the slug describes the batch's content so the tag name alone is enough to recall what shipped. No letter suffixes (`-a`/`-b`), no pseudo-ranges (`v1.11.x`), no slug-only sub-versions sharing a number (`v1.13.15-tools` + `-openspec` + `-agentlint` — split into sequential patches instead).
-- `CHANGELOG.md` is the per-tag release log, most-recent on top. When a new tag is created, add a `## <tag> — <YYYY-MM-DD>` section with a 3–6 sentence paragraph summarizing what shipped, drawn from the commit body. Cross-reference other tags by name when the batch builds on, fixes, or pairs with prior work (e.g. "pairs with `v1.13.12-ws-schemas`", "fixed in `v1.13.5-stability-bundle`"). No nested bullets — one paragraph.
-- Deploy: `cd /opt/boocode && docker compose up --build -d` (or `docker compose build --no-cache boocode && docker compose up -d` if you suspect a layer-cache issue).
-- Git push to Gitea: `GIT_SSH_COMMAND="ssh -i /opt/boocode/secrets/boocode_gitea -o IdentitiesOnly=yes" git push origin <branch>`. The default agent identity is rejected; the in-repo deploy key (`secrets/`, gitignored) is the working one. Transient `Connection reset by peer` retries cleanly after `sleep 5`.
+- Sam often has uncommitted `apps/web` work in flight — stage your own commits **explicitly by path** (never `git add -A`); `docker compose up --build -d boocode` builds the working tree, so a container rebuild also ships his uncommitted web changes.
+- **Deploy by surface:** an `apps/coder` change → `sudo systemctl restart boocoder`; an `apps/web` or `apps/server` change → `docker compose up --build -d boocode` (rebuilds web+server from the working tree). The `boocode` container is `build: .`, so uncommitted changes deploy; web edits are live on the Vite dev server (HMR) but NOT on production (`:9500` / code.indifferentketchup.com) until a rebuild. Use `docker compose build --no-cache boocode && docker compose up -d` if you suspect a layer-cache issue.
+- Cutting a release: name the feature branch DIFFERENTLY from the tag (branch `f1-interrupt-guard`, tag `v2.6.7-interrupt-guard`) — identical names trigger `warning: refname ... is ambiguous`.
+- Per-batch docs live under `openspec/changes/<slug>/{proposal,tasks,design}.md`; shipped batches are snapshots in `openspec/changes/archived/`. New batches follow the proposal+tasks shape (see `openspec/README.md`).
+- Tag naming: `vMAJOR.MINOR.PATCH-slug` (e.g. `v1.13.13-ws-publish`), monotonic per minor — the slug alone recalls what shipped. No letter suffixes, no pseudo-ranges, no slug-only sub-versions sharing a number (split into sequential patches).
+- `CHANGELOG.md` is the per-tag release log, newest on top. New tag → add a `## <tag> — <YYYY-MM-DD>` section, one 3–6 sentence paragraph (no nested bullets) from the commit body; cross-reference related tags by name when the batch builds on / fixes / pairs with prior work.
+- Git push to Gitea: `GIT_SSH_COMMAND="ssh -i /opt/boocode/secrets/boocode_gitea -o IdentitiesOnly=yes" git push origin <branch>`. The default agent identity is rejected; the in-repo deploy key (`secrets/`, gitignored) is the working one. Transient `Connection reset by peer` retries cleanly after `sleep 5`. Keep both remotes synced: push `main` + the release tag to `origin` (Gitea, deploy key above) AND `backup` (`git@github.com:indifferentketchup/boocode.git`, default key).
 - Don't accumulate `.bak-*` files. Clean them up in the same batch or immediately after merge.
-- DB-integration tests opt-in via env var: `DATABASE_URL='postgres://boocode:devpass@localhost:5500/boochat' pnpm -C apps/server test`. Host port is 5500 (mapped from `boocode_db:5432`); password is `${POSTGRES_PASSWORD}` from `.env` (`devpass`), NOT the literal in `.env`'s `DATABASE_URL=postgres://boocode:Ketchup1479@boocode_db:5432/...` line. Pattern: `describe.runIf(!!process.env.DATABASE_URL)(...)` with a `beforeAll` that applies the schema via `sql.unsafe(readFileSync(schemaPath))`. Tests skip cleanly when var is unset. `tool_cost_stats.test.ts` is the reference.
-- Host-side smoke endpoint: `curl http://100.114.205.53:9500/api/...`. The boocode container's port mapping binds to the Tailscale IP, not `0.0.0.0`, so `localhost:9500` doesn't work from the host shell. Same for booterm at `:9501`.
-- Fastify global JSON parser tolerates empty bodies (overridden in `index.ts`); bodyless POSTs (archive, unarchive, stop) work without setting `Content-Type` tricks on the client.
+- DB-integration tests opt-in via env var: `DATABASE_URL='postgres://boocode:devpass@localhost:5500/boochat' pnpm -C apps/server test`. Host port 5500; password is `${POSTGRES_PASSWORD}` from `.env` (`devpass`), NOT the literal in `.env`'s `DATABASE_URL` line. `psql` isn't on host PATH — use `docker exec boocode_db psql -U boocode -d boochat -c "..."`. Pattern: `describe.runIf(!!process.env.DATABASE_URL)(...)` + `beforeAll` applying schema via `sql.unsafe(readFileSync(schemaPath))`. `tool_cost_stats.test.ts` is the reference.
+- Host-side smoke endpoint: `curl http://100.114.205.53:9500/api/...`. The container's port mapping binds to the Tailscale IP, not `0.0.0.0`, so `localhost:9500` doesn't work from the host shell. Same for booterm at `:9501`.
+- Frontend blank-screen / runtime crash: get the stack-trace column offset from the browser console, then `cut -c <start>-<end> apps/web/dist/assets/index-*.js | sed -n '<line>p'` to read the exact minified expression that threw. Watch for `=== null`/`!== null` on optional fields fed an `as unknown as` cast — those bypass tsc.
+- Fastify global JSON parser tolerates empty bodies (overridden in `index.ts`); bodyless POSTs (archive, unarchive, stop) work without `Content-Type` tricks on the client.
 - Event dedup discipline: for any mutation the server publishes via `broker.publishUser`, do NOT add a local `sessionEvents.emit(...)` after the API call — `useUserEvents` forwards the WS frame onto the bus. Frontend mutation handlers must be idempotent (dedup by id, no-op on already-present).
 - `node:20-*` base images ship a `node` user at uid/gid 1000 — delete it (`userdel`/`groupdel` on debian, `deluser`/`delgroup` on alpine) before adding samkintop at 1000.
 - node-pty's compiled `.node` is libc-specific: proddeps and runtime Dockerfile stages must share libc (alpine↔musl or bookworm-slim↔glibc); the TS-only builder stage can stay alpine for speed.
 - pnpm 10 `--frozen-lockfile` skips node-pty's postinstall — the Docker proddeps stage runs `cd node_modules/node-pty && npm run install` to force the native compile.
 - A local PreToolUse hook (`security_reminder_hook.py`) regex-flags Node's older `child_process` spawn helpers as unsafe (false positive even on the File-suffixed variant). Use `spawn` — it's accepted.
-- `/opt/boolab` hosts a working sibling BooCode terminal at `boocode.indifferentketchup.com`. Useful for visual side-by-side comparison on the same iPhone when debugging booterm rendering. Boolab uses Tailwind v3 (`@tailwind base`); boocode uses v4 — many subtle build differences. Don't assume parity.
-- booterm SSHs to the host as `samkintop@100.114.205.53` (the Tailscale IP). The hostname `ubuntu-homelab` (shown in the bash prompt after login) does NOT resolve from inside the container — only the host's `/etc/hosts` knows it. Override via `BOOTERM_SSH_HOST` / `BOOTERM_SSH_USER` env vars in docker-compose if you ever move the shell to a different machine.
-- codecontext sidecar lives at `/opt/boocode/codecontext/`. Sidecar HTTP API at `http://codecontext:8080/v1/<tool_name>` over the `boocode_net` bridge (no host port). BooCode wrappers in `apps/server/src/services/tools/codecontext/`. The `.codecontextignore.template` documents recommended ignore patterns; users copy and adapt to project root manually.
-- codecontext fork at `/opt/forks/codecontext/` — separate git repo (branch `boocode-ts`), pushed via the same boocode_gitea SSH key to `indifferentketchup/codecontext`. Build: `go build ./...`. Test: `go test ./...`. Docker rebuild: `docker compose build --no-cache codecontext`.
-- Go binary: `/snap/go/current/bin/go` (not on PATH by default). Use `export PATH=$PATH:/snap/go/current/bin` or full path for Go commands.
-- `os/exec` child supervisors must explicitly call `child.Wait()` in a goroutine and `os.Exit` on child death. `Signal(0)` returns nil on zombies and is NOT a liveness check. Without `Wait()`, docker's `restart: unless-stopped` policy never fires because the parent stays alive. The `codecontext/shim.go` implementation is the reference pattern.
+- `/opt/boolab` hosts a sibling BooCode at `boocode.indifferentketchup.com` — useful for side-by-side iPhone comparison when debugging booterm rendering. It uses Tailwind v3, boocode uses v4 — don't assume build parity.
+- booterm SSHs to the host as `samkintop@100.114.205.53` (the Tailscale IP). The hostname `ubuntu-homelab` (in the bash prompt) does NOT resolve inside the container. Override via `BOOTERM_SSH_HOST` / `BOOTERM_SSH_USER` env vars in docker-compose if the shell moves to a different machine.
+- codecontext sidecar lives at `/opt/boocode/codecontext/`. HTTP API at `http://codecontext:8080/v1/<tool_name>` over the `boocode_net` bridge (no host port). BooCode wrappers in `apps/server/src/services/tools/codecontext/`. The `.codecontextignore` at project root is honored when `--respect-gitignore` is passed (enabled in the shim).
+- codecontext fork at `/opt/forks/codecontext/` — separate git repo (branch `boocode-ts`), pushed via the boocode_gitea SSH key to `indifferentketchup/codecontext`. Build `go build ./...`; test `go test ./...`. Docker rebuild requires staging the fork first: `tar -czf codecontext/fork.tar.gz -C /opt/forks/codecontext --exclude=.git --exclude=bin .` then `docker compose build --no-cache codecontext` (the Dockerfile COPYs `fork.tar.gz` into the builder stage; Gitea is behind Authelia, no HTTP clone). `fork.tar.gz` is gitignored.
+- Go binary: `/snap/go/current/bin/go` (not on PATH). Use `export PATH=$PATH:/snap/go/current/bin` or the full path.
+- `os/exec` child supervisors must call `child.Wait()` in a goroutine and `os.Exit` on child death. `Signal(0)` returns nil on zombies and is NOT a liveness check. Without `Wait()`, docker's `restart: unless-stopped` never fires because the parent stays alive. `codecontext/shim.go` is the reference.
 
 ## Conventions
 
-- `overflowWrap` not `wordWrap` — TypeScript's CSSStyleDeclaration marks `wordWrap` as deprecated (error 6385).
+Cross-cutting only. Per-app conventions live in the matching `apps/*/CLAUDE.md`.
+
 - No app-layer auth. Authelia handles auth at the reverse proxy. All `broker.publishUser`/`subscribeUser` calls use `'default'` as the user key.
-- TypeScript strict mode. Both apps share `tsconfig.base.json`.
-- Server uses NodeNext module resolution (`.js` extensions in imports).
+- TypeScript strict mode. Both apps share `tsconfig.base.json`. Server + coder use NodeNext module resolution (`.js` extensions in imports).
 - Discriminated unions for type narrowing: `Pane` (by `kind`), `SessionEvent` (by `type`), `InferenceFrame` (by `type`).
-- **Adding a new WS frame type** requires updating BOTH the server's `InferenceFrame` (loose `type:` union + optional fields in `services/inference/turn.ts`) AND the web `WsFrame` (strict discriminated union in `apps/web/src/api/types.ts`). Server publish is permissive; the frontend type is the wire-format gate. The `'usage'` frame added in v1.12.2 needed both sides; missing the web side silently drops the frame at JSON-parse.
-- shadcn primitives live in `components/ui/`. Don't modify them unless adding a new primitive.
-- `inferLanguage()` from `lib/attachments.ts` is the canonical file-extension-to-language map. `CodeBlock.tsx` keeps its own `LANG_MAP` because it also resolves markdown fence names.
-- Two UI event buses: `hooks/sessionEvents.ts` for DB-state events (chat_created, session_updated); `lib/events.ts` for ephemeral UI (`sendToTerminal`, `terminalsRegistry`). Don't merge — different subscriber lifecycles.
-- `vite.config.ts` proxy entries are order-sensitive: more-specific prefixes (`/api/term`, `/ws/term`) must come BEFORE `/api`.
-- Mobile pane URL sync (`Session.tsx`): the `?pane=<id>` effect resets `activePaneIdx` whenever `panes` changes. New-pane creation on mobile must push `?pane=` atomically — `addPaneAndSwitch` is the wrapper that does this. `addSplitPane` returns the new pane id for callers.
-- xterm.js v5 uses canvas rendering — browser doesn't see xterm's selection; the native right-click menu has no working Copy for terminal text. App keybindings (`Cmd/Ctrl-C`, `Cmd/Ctrl-Shift-C`) are the path.
-- **New tools** live in their own `services/<name>.ts` file (see `web_search.ts`, `web_fetch.ts`) — exports a pure `executeFoo(input, ...deps)` for direct test access plus a `ToolDef` wrapper that `loadConfig()`s its real dependencies. Register the ToolDef in `tools.ts` `ALL_TOOLS` (and `READ_ONLY_TOOL_NAMES` if applicable). Inject `fetcher: typeof fetch = fetch` rather than `vi.spyOn(globalThis, 'fetch')` — cleanup is simpler and the production call site stays unchanged.
-- **Sentinels** are `role='system'` rows with structured `metadata.kind` (`cap_hit`, `doom_loop`). UI-only — `buildMessagesPayload` strips them via `isAnySentinel` so the LLM never sees them. A new kind requires arms in `MessageMetadata` in BOTH `apps/server/src/types/api.ts` AND `apps/web/src/api/types.ts`, plus a render branch in `apps/web/src/components/MessageBubble.tsx`.
-- **ReadableStream test stubs** use `pull()` (not `start()`) so chunks are produced lazily — `start()` enqueues everything and calls `controller.close()` before the consumer reads, so a subsequent `reader.cancel()` finds the stream already closed and the `cancel()` callback never fires. Also provide MORE chunks than the test will consume so the source stays in 'readable' state when cancel runs (e.g. cap test reads ~6 chunks, stub provides 10).
-- Tool-name whitelists must derive from `ALL_TOOLS` in `services/tools.ts`, never hardcoded. `services/agents.ts` `ALL_TOOL_NAMES` had this drift class until v1.12 — same pattern applies to any future tool-aware code.
-- Agent registry lives at `data/AGENTS.md` (global, bind-mounted at `/data/AGENTS.md`). No per-project `AGENTS.md` in this repo — removed in v1.12 to eliminate the two-files-must-stay-in-sync drift. The `getAgentsForProject` per-project override mechanism remains for *other* projects.
-- MCP stdio transport uses newline-delimited JSON (NDJSON), NOT LSP-style `Content-Length` headers. The `codecontext/shim.go` framing implementation is the reference; per the MCP spec (modelcontextprotocol.io/specification/server/transports).
-- **Workspace dependency pattern** (`apps/coder` → `@boocode/server`): the consuming package adds `"@boocode/server": "workspace:*"` in `package.json`. The provider's `package.json` needs `exports` with `types` + `default` conditions per subpath: `"./inference": { "types": "./dist/.../index.d.ts", "default": "./dist/.../index.js" }`. Without the `types` condition, NodeNext resolution can't find `.d.ts` files and tsc fails with "Cannot find module" in the consumer.
-- **JSONB columns**: use `sql.json(value as never)` — NOT `${JSON.stringify(value)}::jsonb` which double-serializes (stores a JSON string instead of a JSON object/array). Pattern established in `parts.ts`, `settings.ts`.
-- **`payload.ts:loadContext` SELECT**: must include every `Session` field that downstream code reads. The tool phase reads `session.allowed_read_paths`; if the SELECT omits it, cross-repo read grants silently fail. The `Session` TypeScript type doesn't catch this because `sql<Session[]>` doesn't enforce column coverage.
+- **Adding a new WS frame type** (cross-app): add it to `WsFrameSchema` in `packages/contracts/src/ws-frames.ts` (single source of truth; rebuild with `pnpm -C packages/contracts build`). The server's `InferenceFrame` loose union (`services/inference/turn.ts`) and the web's strict `WsFrame` discriminated union (`apps/web/src/api/types.ts`) still exist separately and also need updating. Server publish is permissive; the frontend type is the wire-format gate — missing the web side silently drops the frame at JSON-parse.
+- **Sentinels** (cross-app) are `role='system'` rows with structured `metadata.kind` (`cap_hit`, `doom_loop`). UI-only — `buildMessagesPayload` strips them via `isAnySentinel` so the LLM never sees them. `MessageMetadata` is single-sourced in `@boocode/contracts` (`packages/contracts/src/message-metadata.ts`). A new kind requires updating that file and rebuilding the package, plus a render branch in `apps/web/src/components/MessageBubble.tsx`.
+- **Provider snapshot types** (`ProviderSnapshotEntry`, `ProviderModel`, `ProviderMode`, `ThinkingOption`, `AgentCommand`, `ProviderSnapshotStatus`) are single-sourced in `@boocode/contracts` (`packages/contracts/src/provider-snapshot.ts`); `apps/coder/src/services/provider-types.ts` re-exports them. Edit the package source; there is no hand-synced web copy to update.
+- **`@boocode/contracts`** single-sources cross-app wire contracts via per-subpath built-dist exports, consumed by all four apps (incl. `apps/coder/web`): `./ws-frames`, `./provider-snapshot`, `./provider-config` (Zod schemas), `./message-metadata` (`MessageMetadata`/`ErrorReason`/`AgentSessionConfig`), `./worktree-risk`. It builds BEFORE every consumer (root build, Dockerfile, coder deploy). Its `WsFrame` is the loose `z.infer` of `WsFrameSchema` (payloads `unknown`); the web's richer strict `WsFrame` union is **deliberately web-local** (`apps/web/src/api/types.ts`), bridged to the validated frame by a cast — don't move it into the package. Consume built `dist` via the exports map; never add the package to a tsconfig `references` array.
+- **JSONB columns**: use `sql.json(value as never)` — NOT `${JSON.stringify(value)}::jsonb` which double-serializes (stores a JSON string instead of an object/array). Pattern in `parts.ts`, `settings.ts`.
+- Skills live in `data/skills/<vendor>/`; Sam's own namespace is `boocode/` (`committing-changes`, `using-worktrees`, `improving-boocode-guidance`, `systematic-debugging`) — `SKILL.md` + optional `eval.yaml` (gerund names; eval = `skill:` + `tasks:` of `prompt`+`grader`, incl. a negative-trigger task). `data/skills/` is canonical; a divergent mirror at `/opt/skills/` exists.
+
+### Coding standards
+
+Coding standards live in `docs/coding-standards/` (canonical, human-readable). They are exposed to Claude Code through per-file-type/subsystem index files under `.claude/rules/coding-standards/`. Each index is a path-scoped rule that lists the standards relevant to its `paths:` glob with a one-line description of each. When Claude reads a file matching an index's `paths:`, it loads only that small index and then decides which (if any) standards to open with Read — the full text of a standard is never loaded automatically, and standards do not appear in the skills picker. Browse `docs/coding-standards/` for the readable form.

CURRENT.md

@@ -1,10 +1,9 @@
 # Current focus
 
-Last updated: 2026-05-26
+Last updated: 2026-06-02
 
-- **Batch:** v2.3-provider-lifecycle (openspec drafted; not started)
-- **Branch:** `main`
-- **Blockers:** none
-- **Last shipped:** `v2.2.2-xml-placeholder-reject`
+- **Last shipped:** `v2.7.8-ember-coder-tabs-model-chips` (2026-06-01)
+- **Branch:** `codebase-audit-cleanup` (audit + cleanup epic, off main HEAD)
+- **In progress:** Phase 3 — stale comments + docs refresh
 
-Update this file when starting or finishing a batch. Agents: read this first for session intent; if stale vs `CHANGELOG.md`, trust CHANGELOG for shipped state.
+See `CHANGELOG.md` for the full shipped history. That file is always authoritative; this file is a quick orientation pointer only.

Dockerfile

@@ -5,11 +5,15 @@ RUN corepack enable
 WORKDIR /build
 
 COPY package.json pnpm-workspace.yaml pnpm-lock.yaml tsconfig.base.json ./
+COPY packages/contracts/package.json ./packages/contracts/
 COPY apps/server/package.json ./apps/server/
 COPY apps/web/package.json ./apps/web/
 
 RUN pnpm install --frozen-lockfile
 
+# @boocode/contracts must be present before `pnpm build`, which builds it FIRST
+# (root build script) so apps/web can resolve its compiled dist via the exports map.
+COPY packages/contracts ./packages/contracts
 COPY apps/server ./apps/server
 COPY apps/web ./apps/web
 
@@ -20,6 +24,9 @@ RUN pnpm deploy --filter=@boocode/server --prod --legacy /out/server
 
 FROM node:20-alpine AS runtime
 RUN apk add --no-cache ripgrep git openssh-client
+# The container runs as root but bind-mounts host project repos owned by uid 1000;
+# trust them so git read/write tools (git_status, the git diff panel) work over the mount.
+RUN git config --system --add safe.directory '*'
 RUN mkdir -p /root/.ssh && ssh-keyscan -p 2222 -H 100.114.205.53 git.indifferentketchup.com >> /root/.ssh/known_hosts && chmod 700 /root/.ssh && chmod 600 /root/.ssh/known_hosts
 WORKDIR /app
 

LICENSE

@@ -1,661 +1,21 @@
-                    GNU AFFERO GENERAL PUBLIC LICENSE
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-want it, that you can change the software or use pieces of it in new
-free programs, and that you know you can do these things.
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README.md

@@ -58,7 +58,7 @@ upstream and inject `Remote-User`. Postgres binds loopback only.
 BooCoder runs as a **host systemd service** (`boocoder.service`, port `:9502`), not in Docker:
 
 ```bash
-pnpm -C apps/server build && pnpm -C apps/coder build
+pnpm -C packages/contracts build && pnpm -C apps/server build && pnpm -C apps/coder build
 sudo systemctl restart boocoder
 curl http://100.114.205.53:9502/api/health
 ```
@@ -84,3 +84,7 @@ See [`boocode_roadmap.md`](boocode_roadmap.md) for full version history. Highlig
 ## Planned
 
 - **v2.3 provider lifecycle** — config-backed provider registry (`/data/coder-providers.json`), enable/disable toggles, two-tier probe (openspec drafted). See [`CURRENT.md`](CURRENT.md).
+
+## License
+
+MIT — see [`LICENSE`](LICENSE).

apps/booterm/package.json

@@ -15,7 +15,6 @@
     "fastify": "^4.28.1",
     "node-pty": "^1.0.0",
     "pg": "^8.13.0",
-    "tslib": "^2.6.3",
     "zod": "^3.23.8"
   },
   "devDependencies": {
@@ -24,5 +23,5 @@
     "tsx": "^4.16.2",
     "typescript": "^5.5.0"
   },
-  "license": "AGPL-3.0-only"
+  "license": "MIT"
 }

apps/booterm/src/config.ts

@@ -9,7 +9,7 @@ const ConfigSchema = z.object({
   TMUX_CONF_PATH: z.string().default('/etc/booterm/tmux.conf'),
 });
 
-export type Config = z.infer<typeof ConfigSchema>;
+type Config = z.infer<typeof ConfigSchema>;
 
 let cached: Config | null = null;
 

apps/booterm/src/db.ts

@@ -10,7 +10,7 @@ export function getPool(databaseUrl: string): pg.Pool {
   return pool;
 }
 
-export interface SessionInfo {
+interface SessionInfo {
   id: string;
   project_id: string;
   project_path: string;

apps/booterm/src/pty/pty.ts

@@ -1,7 +1,7 @@
 import * as pty from 'node-pty';
 import type { IPty } from 'node-pty';
 
-export interface AttachPtyOptions {
+interface AttachPtyOptions {
   sessionName: string;
   projectRoot: string;
   cols: number;

apps/coder/.env.host

@@ -13,3 +13,5 @@ GITEA_USER=indifferentketchup
 GITEA_SSH_HOST=100.114.205.53:2222
 MCP_CONFIG_PATH=/data/mcp.json
 SKILLS_ROOT=/opt/boocode/data/skills
+CODER_PROVIDERS_PATH=/opt/boocode/data/coder-providers.json
+CLAUDE_SDK_BACKEND=1

apps/coder/CLAUDE.md

@@ -0,0 +1,34 @@
+# apps/coder — BooCoder (deep reference)
+
+> Per-app engineering notes for `apps/coder/src/`. BooCoder runs as a **systemd service on the host** (`boocoder.service`), NOT in Docker — Fastify at port 9502, postgres at `127.0.0.1:5500`. Cross-cutting commands, database, environment, workflow, and cross-app contracts live in the **root `CLAUDE.md`**. This file auto-loads when you read/edit files under `apps/coder/`.
+
+## Probe & provider discovery
+
+- **`services/provider-registry.ts`** — Static registry of provider metadata (label, transport, model source). `PROVIDERS` array, `PROVIDERS_BY_NAME` map. 5 providers: boocode (native), opencode (acp), goose (pty), claude (pty), qwen (pty). `PROBED_AGENT_NAMES` derives from it — adding/removing providers means editing this file, not the frontend.
+- **`services/agent-probe.ts`** — Startup probe via direct `exec()` (not SSH): discovers installed agents, versions, ACP support, models. Qwen models from `~/.qwen/settings.json`; Claude models static from the registry. Persisted to `available_agents`.
+- **`routes/providers.ts`** — `GET /api/providers` returns installed providers with models. Transport reflects actual capability (checks `supports_acp` from DB, not just registry preference). The apps/server side is "Provider picker dispatch" (see `apps/server/CLAUDE.md`).
+- **Provider snapshot lifecycle** (`services/`): `provider-config.ts` (Zod config, never-throws) → `provider-config-registry.ts` (`buildResolvedRegistry`, singleton) → `provider-snapshot.ts` (two-tier probe: tier-1 fast presence, tier-2 cold ACP probe skipped unless force / stale `PROVIDER_PROBE_TTL_MS` 24h / dbEmpty; cached). Verify live: `curl http://100.114.205.53:9502/api/providers/snapshot` — returns providers + models + commands, the exact shape `AgentComposerBar` renders.
+- `PATCH /api/providers/config` replaces a provider id's override object **wholesale** (per-id shallow merge) — to flip one field send `{...existing, enabled}`, or a custom ACP entry's `command`/`label` is wiped and it drops out of the resolved registry. `data/coder-providers.json` is **gitignored** (live runtime config — the coder reads AND writes it on UI toggles); tracked reference is `data/coder-providers.example.json`. The loader falls back to `{providers:{}}` (built-ins only) when absent, so a fresh checkout needs no copy.
+
+## Build, deploy, dispatch
+
+- **Workspace dependency on `@boocode/server`**: imports `createInferenceRunner`, `createBroker`, `ALL_TOOLS`, `appendMcpTools` from the server's compiled `dist/`. apps/server's `package.json` has an `exports` map with `types` conditions for NodeNext resolution. **apps/server must build FIRST.**
+- Build + deploy: `pnpm -C packages/contracts build && pnpm -C apps/server build && pnpm -C apps/coder build && sudo systemctl restart boocoder`. Env file at `apps/coder/.env.host`. Service file at `/etc/systemd/system/boocoder.service`.
+- After `pnpm -C apps/coder build` the host service keeps running the OLD process until `sudo systemctl restart boocoder` — a stale process shows **new routes 404 with `{error:'not found'}` while old routes still 200** (the `/api` not-found handler shape). Restart, don't re-debug.
+- `:9502/api/health` is down ~15–20s after a boocoder restart while the startup agent-probe scan runs — retry; an early connection-refused is not a failed deploy.
+- Agent dispatch spawns binaries directly using `install_path` from `available_agents` — no `spawn('sh', ['-c', ...])` (fails under systemd). Paseo's pattern: `spawn(fullBinaryPath, argsArray, { cwd })`.
+- systemd hardening: only `NoNewPrivileges=true` is safe. `ProtectSystem`, `ProtectHome`, `PrivateTmp` all break agent dispatch (agents need full filesystem access to read configs, write to worktrees).
+- `apps/server/tsconfig.json` has `declaration: true` so `.d.ts` files exist for workspace consumers. The provider's `package.json` needs `exports` with `types` + `default` conditions per subpath (`"./inference": { "types": "./dist/.../index.d.ts", "default": "./dist/.../index.js" }`) — without the `types` condition, NodeNext can't find `.d.ts` files and tsc fails "Cannot find module" here.
+- Write tools (`edit_file`, `create_file`, `delete_file`, `apply_pending`, `rewind`) queue in `pending_changes`. Nothing hits disk until `apply_pending`. `write_guard.ts` validates paths (resolve + prefix-check, no realpath since files may not exist for creates).
+
+## Backends
+
+> Behavioral overview + flows + data model: see [/docs/coder-backends.md](/docs/coder-backends.md). The notes below are the deep per-fact reference.
+
+- **opencode** runs as a warm HTTP server (`services/backends/opencode-server.ts` — `opencode serve` per BooCoder process, one opencode session per BooCode session, resumed via `agent_sessions`). goose/qwen/claude dispatch **one-shot** ACP/PTY with no ctx/token usage; only native `boocode` (llama-swap) tracks ctx.
+- **opencode SSE** (`opencode-server.ts`): live streaming is `session.next.text.delta` / `.reasoning.delta` / `.tool.{called,success,failed}` — NOT `message.part.*` (terminal/post-hoc). `client.event.subscribe({ directory })` MUST pass the session's worktree dir; omit it and opencode scopes events to the server `process.cwd()` → zero session events (empty turns, 180s timeout). Each live session owns its own subscribe loop + AbortController (a `sessionID` demux guard drops cross-session events when two share a dir). Turn completes on `session.idle`; `promptAsync` is fire-and-forget (204).
+- **opencode model strings** must be provider-prefixed (`llama-swap/<model>`) AND exist in `~/.config/opencode/opencode.json` `provider.llama-swap.models` — not merely loadable by llama-swap. `parseModel` infers `llama-swap/` for a bare id; the dispatcher coalesces empty→DEFAULT_MODEL then prefixes. `agent-probe` populates opencode's `available_agents.models` via `mergeLlamaSwap` (fetches `/v1/models`); empty model list → frontend sends `''` → no inference (empty turn).
+- **agent_sessions resume**: `config_hash = sha256('opencode_server|<model>')` — must NOT include the server port (random per boot; breaks cross-restart resume). Keyed `(chat_id, agent)` — the tab/chat is the context unit (two opencode tabs = two contexts sharing one worktree). `chat_id` CASCADEs from `chats`; `session_id`/`worktree_id` are informational `SET NULL`. The `worktrees` table (one-per-session, survives session delete) supersedes the defanged `session_worktrees`. `tasks.chat_id` threads the tab id to the dispatcher; `runOpenCodeServerTask` resolves-or-creates a chat when null. The `@opencode-ai/sdk` v2 client takes flattened params (`{sessionID, directory, parts, model:{providerID,modelID}}`), `createOpencodeClient` from `@opencode-ai/sdk/v2/client`.
+- **Claude SDK backend tool RESULTS arrive as `type:'user'` SDK messages** (tool_result content blocks): `mapSdkMessage` (`claude-sdk-map.ts`) MUST map the `user` case → a terminal `tool_update` (completed/failed + output), else the tool_call persists `status:'running'` and the UI spinner never stops. The dispatcher's `tool_update` path then publishes + persists it.
+- **ACP command discovery is async**: `acp-probe.ts` must poll after `newSession` for `available_commands_update` (commands arrive in a later notification; reading synchronously captures 0). PTY providers (claude) discover from disk via `claude-command-discovery.ts` (`~/.claude/commands` + `enabledPlugins`, bare names, deduped). `AgentCommand.kind` tags `'command'` vs `'skill'`; `CoderPane`'s `slashGroups` splits them into icon'd groups. `SlashCommandPicker`'s `groups?` prop is opt-in.
+- **A new per-message coder field silently drops unless you update every mapper**: the HTTP read SELECT + `mapCoderMessageRow` (`apps/coder/src/routes/messages.ts`), **the WS `snapshot` SELECT (`apps/coder/src/routes/ws.ts`)** — it has its OWN column list and the client's `snapshot` handler `setMessages`-overwrites the HTTP load, so a field present in the HTTP route but absent here shows live yet vanishes on refresh — `CoderPane.tsx` (`RawCoderMessage`/`CoderMessage`/`mapCoderTimelineRow` + the live `message_complete` WS reducer), `CoderMessageWire` (`CoderMessageList.tsx`), and `api/types.ts`. The client `mapCoderTimelineRow` whitelists fields — easiest to forget. This bit `model` twice: the client chain (`v2.7.9`) and then the WS snapshot SELECT (`v2.7.11`) — the chip showed live but vanished on coder refresh until both were fixed.

apps/coder/Dockerfile

@@ -7,7 +7,6 @@ WORKDIR /build
 COPY package.json pnpm-workspace.yaml pnpm-lock.yaml tsconfig.base.json ./
 COPY apps/server/package.json ./apps/server/
 COPY apps/coder/package.json ./apps/coder/
-COPY apps/coder/web/package.json ./apps/coder/web/
 
 RUN pnpm install --frozen-lockfile
 
@@ -16,7 +15,6 @@ COPY apps/server ./apps/server
 RUN pnpm -C apps/server build
 
 COPY apps/coder ./apps/coder
-RUN pnpm -C apps/coder/web build
 RUN pnpm -C apps/coder build
 
 RUN pnpm deploy --filter=@boocode/coder --prod --legacy /out/coder
@@ -27,7 +25,6 @@ RUN apt-get update && apt-get install -y --no-install-recommends ripgrep git ope
 WORKDIR /app
 
 COPY --from=builder /out/coder ./
-COPY --from=builder /build/apps/coder/web/dist ./web
 
 ENV NODE_ENV=production
 EXPOSE 3000

apps/coder/package.json

@@ -13,11 +13,13 @@
     "test": "vitest run"
   },
   "dependencies": {
+    "@boocode/contracts": "workspace:*",
     "@agentclientprotocol/sdk": "^0.22.1",
+    "@anthropic-ai/claude-agent-sdk": "^0.3.159",
     "@boocode/server": "workspace:*",
-    "@fastify/static": "^7.0.4",
     "@fastify/websocket": "^10.0.1",
     "@modelcontextprotocol/sdk": "^1.29.0",
+    "@opencode-ai/sdk": "~1.15.0",
     "fastify": "^4.28.1",
     "postgres": "^3.4.4",
     "ws": "^8.18.0",
@@ -30,5 +32,5 @@
     "typescript": "^5.5.0",
     "vitest": "^3.0.0"
   },
-  "license": "AGPL-3.0-only"
+  "license": "MIT"
 }

apps/coder/src/config.ts

@@ -23,11 +23,33 @@ const ConfigSchema = z.object({
   GITEA_TOKEN: z.string().optional(),
   GITEA_SSH_HOST: z.string().default('100.114.205.53:2222'),
   MCP_CONFIG_PATH: z.string().optional(),
+  // v2.3: config-backed provider overrides/custom-ACP entries merged over the
+  // hardcoded built-ins. Missing file = built-ins only (see provider-config.ts).
+  CODER_PROVIDERS_PATH: z.string().default('/data/coder-providers.json'),
+  // v2.3 phase 2: tier-2 (cold ACP probe) is skipped when available_agents was
+  // probed more recently than this. 24h default — stale model lists self-heal
+  // on the next snapshot; an explicit /refresh always re-probes.
+  PROVIDER_PROBE_TTL_MS: z.coerce.number().int().positive().default(86_400_000),
   // v2.0.5: cheaper model for titles, summaries, labeling.
   FAST_MODEL: z.string().optional(),
   // SSH access to the host for external agent dispatch (Phase 5)
   BOOCODER_SSH_HOST: z.string().default('100.114.205.53'),
   BOOCODER_SSH_USER: z.string().default('samkintop'),
+  // v2.6 Phase 3 (lifecycle hardening). Idle TTL: evict a non-busy warm backend
+  // (opencode server / warm-ACP child) after this long with no turn — its worktree
+  // + agent_sessions row persist, so the next turn re-spawns + reattaches. 30 min
+  // default (design §6).
+  AGENT_POOL_IDLE_TTL_MS: z.coerce.number().int().positive().default(1_800_000),
+  // LRU cap: max live warm backends before the least-recently-used (non-busy) ones
+  // are evicted. Bounds the long-lived-daemon's per-(chat,agent) Map growth.
+  AGENT_POOL_MAX_LIVE: z.coerce.number().int().positive().default(10),
+  // Periodic sweep cadence (idle/LRU pool eviction + orphan-worktree reap). 60s
+  // mirrors the apps/server truncation/stale-streaming sweeper.
+  LIFECYCLE_SWEEP_INTERVAL_MS: z.coerce.number().int().positive().default(60_000),
+  // Orphan-worktree grace: an on-disk worktree dir with no live `worktrees` row is
+  // only reaped after it's been untouched this long (avoids sweeping a dir mid
+  // ensureSessionWorktree create). 1h default.
+  ORPHAN_WORKTREE_GRACE_MS: z.coerce.number().int().positive().default(3_600_000),
 });
 
 export type Config = z.infer<typeof ConfigSchema>;

apps/coder/src/index.ts

@@ -1,12 +1,5 @@
-import { resolve, dirname } from 'node:path';
-import { fileURLToPath } from 'node:url';
-import { existsSync } from 'node:fs';
 import Fastify from 'fastify';
 import fastifyWebsocket from '@fastify/websocket';
-import fastifyStatic from '@fastify/static';
-
-const __filename = fileURLToPath(import.meta.url);
-const __dirname = dirname(__filename);
 import { loadConfig } from './config.js';
 import { getSql, applySchema, pingDb, closeDb } from './db.js';
 import { startMcpServer } from './services/mcp-server.js';
@@ -16,7 +9,7 @@ import { createInferenceRunner } from '@boocode/server/inference';
 import { createBroker } from '@boocode/server/broker';
 import { appendMcpTools, ALL_TOOLS } from '@boocode/server/tools';
 import type { Config as ServerConfig } from '@boocode/server/config';
-import type { WsFrame } from '@boocode/server/ws-frames';
+import type { WsFrame } from '@boocode/contracts/ws-frames';
 // v2.0.0 Phase 2C: write tools + adapter for BooChat ToolDef compatibility.
 import { WRITE_TOOLS } from './services/tools/index.js';
 import { adaptWriteTool } from './services/tools/adapter.js';
@@ -25,17 +18,24 @@ import { setInferenceContext, clearInferenceContext } from './services/tools/inf
 import { registerMessageRoutes } from './routes/messages.js';
 import { registerSkillRoutes } from './routes/skills.js';
 import { registerPendingRoutes } from './routes/pending.js';
+import { registerCheckpointRoutes } from './routes/checkpoints.js';
+import { registerAgentSessionRoutes } from './routes/agent-sessions.js';
 import { registerTaskRoutes } from './routes/tasks.js';
 import { registerInboxRoutes } from './routes/inbox.js';
 import { registerStatsRoutes } from './routes/stats.js';
 import { registerArenaRoutes } from './routes/arena.js';
 import { registerProviderRoutes } from './routes/providers.js';
+import { registerWorktreeSafetyRoutes } from './routes/worktree-safety.js';
+import { registerLifecycleRoutes } from './routes/lifecycle.js';
 import { registerWebSocket } from './routes/ws.js';
 // Phase 4: dispatcher + agent probe
 import { createDispatcher } from './services/dispatcher.js';
+import { agentPool } from './services/agent-pool.js';
+import { createOrphanWorktreeReaper } from './services/orphan-worktree-reaper.js';
 import { probeAgents } from './services/agent-probe.js';
 import { getProviderSnapshot, persistProbedModels } from './services/provider-snapshot.js';
 import { setPermissionHooks } from './services/permission-waiter.js';
+import { publishAgentStatus } from './services/agent-status-publish.js';
 import { homedir } from 'node:os';
 
 async function main() {
@@ -76,6 +76,21 @@ async function main() {
   // Broker: in-memory pub/sub for session + user channel streaming.
   const broker = createBroker(app.log);
 
+  // agent-status-normalize (#10): the permission hooks carry only taskId +
+  // sessionId, but the tasks row holds the (chat_id, agent) pair the status frame
+  // is keyed on. Resolve it best-effort so a blocked/working status accompanies
+  // every permission_requested/permission_resolved. Returns null when the task
+  // lacks a chat_id or agent (sessionless creators) — we simply skip the status.
+  const resolveChatAgent = async (
+    taskId: string,
+  ): Promise<{ chatId: string; agent: string } | null> => {
+    const [row] = await sql<{ chat_id: string | null; agent: string | null }[]>`
+      SELECT chat_id, agent FROM tasks WHERE id = ${taskId}
+    `;
+    if (!row?.chat_id || !row.agent) return null;
+    return { chatId: row.chat_id, agent: row.agent };
+  };
+
   setPermissionHooks({
     onPrompt: async (prompt) => {
       await sql`
@@ -90,6 +105,18 @@ async function main() {
         ...(prompt.input ? { input: prompt.input } : {}),
         options: prompt.options.map((o) => ({ option_id: o.optionId, label: o.label })),
       } as WsFrame);
+      // #10: agent is blocked on a human decision.
+      const ca = await resolveChatAgent(prompt.taskId).catch(() => null);
+      if (ca) {
+        publishAgentStatus(
+          broker.publishFrame,
+          prompt.sessionId,
+          ca.chatId,
+          ca.agent,
+          'blocked',
+          'permission_request',
+        );
+      }
     },
     onResolved: async (taskId, sessionId) => {
       await sql`
@@ -100,6 +127,18 @@ async function main() {
         task_id: taskId,
         session_id: sessionId,
       } as WsFrame);
+      // #10: human responded — agent resumes work.
+      const ca = await resolveChatAgent(taskId).catch(() => null);
+      if (ca) {
+        publishAgentStatus(
+          broker.publishFrame,
+          sessionId,
+          ca.chatId,
+          ca.agent,
+          'working',
+          'permission_resolved',
+        );
+      }
     },
   });
 
@@ -178,41 +217,48 @@ async function main() {
   // Phase 4: dispatcher — polls tasks table and runs inference
   const dispatcher = createDispatcher({ sql, inference: inferenceApi, broker, log: app.log, config });
   dispatcher.start();
-  app.addHook('onClose', () => dispatcher.stop());
+
+  // v2.6 Phase 3: configure + start the agent-pool lifecycle sweep (idle-TTL +
+  // LRU-cap eviction of warm backends, plus each backend's proactive health probe)
+  // and the orphan-worktree reaper. Both run on the same periodic timer.
+  agentPool.configure({
+    idleTtlMs: config.AGENT_POOL_IDLE_TTL_MS,
+    maxLive: config.AGENT_POOL_MAX_LIVE,
+    sweepIntervalMs: config.LIFECYCLE_SWEEP_INTERVAL_MS,
+    log: app.log,
+  });
+  agentPool.startReaper(app.log);
+  const orphanReaper = createOrphanWorktreeReaper({
+    sql,
+    log: app.log,
+    intervalMs: config.LIFECYCLE_SWEEP_INTERVAL_MS,
+    graceMs: config.ORPHAN_WORKTREE_GRACE_MS,
+  });
+  orphanReaper.start();
+
+  app.addHook('onClose', async () => {
+    // stop() first so in-flight dispatcher turns settle, then stop the reapers and
+    // drain the pool (kills opencode server + warm ACP children).
+    await dispatcher.stop();
+    orphanReaper.stop();
+    await agentPool.dispose();
+  });
 
   // Register routes
   registerMessageRoutes(app, sql, broker, inferenceApi);
   registerSkillRoutes(app, sql, broker, inferenceApi);
   registerPendingRoutes(app, sql);
-  registerTaskRoutes(app, sql, inferenceApi);
+  registerCheckpointRoutes(app, sql);
+  registerAgentSessionRoutes(app, sql);
+  registerTaskRoutes(app, sql, inferenceApi, dispatcher.cancelExternalTask);
   registerInboxRoutes(app, sql);
   registerStatsRoutes(app, sql);
   registerArenaRoutes(app, sql);
   registerProviderRoutes(app, sql, config);
+  registerWorktreeSafetyRoutes(app, sql);
+  registerLifecycleRoutes(app, sql);
   registerWebSocket(app, sql, broker);
 
-  // Serve static frontend (built web app). In production, the dist/ is
-  // copied to ../web relative to the dist/ directory at /app/web. In dev,
-  // check adjacent to the source.
-  const webRoot = resolve(__dirname, '../web');
-  if (existsSync(webRoot)) {
-    await app.register(fastifyStatic, {
-      root: webRoot,
-      prefix: '/',
-      // Don't intercept /api routes — static only serves files that exist.
-      wildcard: false,
-    });
-    // SPA fallback: serve index.html for non-API routes that don't match a file.
-    app.setNotFoundHandler(async (req, reply) => {
-      if (req.url.startsWith('/api')) {
-        reply.code(404);
-        return { error: 'not found' };
-      }
-      return reply.sendFile('index.html');
-    });
-    app.log.info(`serving frontend from ${webRoot}`);
-  }
-
   // Graceful shutdown
   const shutdown = async () => {
     app.log.info('shutting down');

apps/coder/src/routes/__tests__/agent-sessions.routes.test.ts

@@ -0,0 +1,75 @@
+import { describe, it, expect } from 'vitest';
+import Fastify, { type FastifyInstance } from 'fastify';
+import { registerAgentSessionRoutes } from '../agent-sessions.js';
+import type { Sql } from '../../db.js';
+
+// Mock the porsager surface this route uses: a tagged-template `sql` dispatched by
+// query substring. Two queries: the session-existence check and the agent_sessions
+// JOIN. We return post-coercion shapes (booleans/strings) exactly as porsager would
+// hand them to the route — `has_session` already a JS boolean, `last_active_at` a
+// string|null — so the asserted JSON matches the API contract end-to-end.
+interface MockState {
+  sessionExists: boolean;
+  rows: Array<{ agent: string; status: string; has_session: boolean; last_active_at: string | null }>;
+}
+
+function mockSql(state: MockState): Sql {
+  return ((strings: TemplateStringsArray) => {
+    const q = strings.join('');
+    if (q.includes('SELECT id FROM sessions')) {
+      return Promise.resolve(state.sessionExists ? [{ id: 'session-1' }] : []);
+    }
+    if (q.includes('FROM agent_sessions')) {
+      return Promise.resolve(state.rows);
+    }
+    return Promise.resolve([]);
+  }) as unknown as Sql;
+}
+
+function buildApp(state: MockState): FastifyInstance {
+  const app = Fastify();
+  registerAgentSessionRoutes(app, mockSql(state));
+  return app;
+}
+
+describe('GET /api/sessions/:id/agent-sessions', () => {
+  it('returns the per-(chat,agent) rows in the contracted shape', async () => {
+    const app = buildApp({
+      sessionExists: true,
+      rows: [
+        { agent: 'opencode', status: 'active', has_session: true, last_active_at: '2026-05-31T12:00:00.000Z' },
+        { agent: 'goose', status: 'idle', has_session: false, last_active_at: null },
+      ],
+    });
+    const res = await app.inject({ method: 'GET', url: '/api/sessions/session-1/agent-sessions' });
+    expect(res.statusCode).toBe(200);
+    const body = res.json();
+    expect(Array.isArray(body)).toBe(true);
+    expect(body).toEqual([
+      { agent: 'opencode', status: 'active', has_session: true, last_active_at: '2026-05-31T12:00:00.000Z' },
+      { agent: 'goose', status: 'idle', has_session: false, last_active_at: null },
+    ]);
+    // Contract field types.
+    expect(typeof body[0].agent).toBe('string');
+    expect(typeof body[0].status).toBe('string');
+    expect(typeof body[0].has_session).toBe('boolean');
+    expect(body[1].last_active_at).toBeNull();
+    await app.close();
+  });
+
+  it('returns an empty array when the session has no agent_sessions rows', async () => {
+    const app = buildApp({ sessionExists: true, rows: [] });
+    const res = await app.inject({ method: 'GET', url: '/api/sessions/session-1/agent-sessions' });
+    expect(res.statusCode).toBe(200);
+    expect(res.json()).toEqual([]);
+    await app.close();
+  });
+
+  it('404s when the session does not exist', async () => {
+    const app = buildApp({ sessionExists: false, rows: [] });
+    const res = await app.inject({ method: 'GET', url: '/api/sessions/nope/agent-sessions' });
+    expect(res.statusCode).toBe(404);
+    expect(res.json()).toEqual({ error: 'session not found' });
+    await app.close();
+  });
+});

apps/coder/src/routes/__tests__/chat-resolve.test.ts

@@ -0,0 +1,110 @@
+import { describe, it, expect } from 'vitest';
+import { resolveChatId } from '../chat-resolve.js';
+import type { Sql } from '../../db.js';
+
+// Mock the porsager/postgres surface that chat-resolve.ts uses: a tagged-template
+// `tx` (dispatched by query substring), `tx.json`, and `sql.begin(fn)` which just
+// runs fn(tx). Captures the value written back to workspace_panes so we can assert
+// the WorkspaceState envelope survives the UPDATE.
+interface MockState {
+  stored: unknown; // initial sessions.workspace_panes value
+  existingChatOpen: boolean; // whether `SELECT id FROM chats ...` finds the active chat
+  newChatId: string;
+  written?: unknown; // captured tx.json(...) payload from `UPDATE sessions`
+  inserted: boolean; // whether INSERT INTO chats ran
+}
+
+interface MockTx {
+  (strings: TemplateStringsArray): Promise<unknown>;
+  json: (v: unknown) => unknown;
+}
+
+function mockSql(state: MockState): Sql {
+  const tx = ((strings: TemplateStringsArray) => {
+    const q = strings.join('');
+    if (q.includes('SELECT workspace_panes FROM sessions')) {
+      return Promise.resolve([{ workspace_panes: state.stored }]);
+    }
+    if (q.includes('FROM chats')) {
+      return Promise.resolve(state.existingChatOpen ? [{ id: 'placeholder' }] : []);
+    }
+    if (q.includes('INSERT INTO chats')) {
+      state.inserted = true;
+      return Promise.resolve([{ id: state.newChatId }]);
+    }
+    if (q.includes('UPDATE sessions')) {
+      return Promise.resolve([]);
+    }
+    return Promise.resolve([]);
+  }) as unknown as MockTx;
+  tx.json = (v: unknown) => {
+    state.written = v;
+    return v;
+  };
+  const sql = {
+    begin: (fn: (t: Sql) => Promise<unknown>) => fn(tx as unknown as Sql),
+  };
+  return sql as unknown as Sql;
+}
+
+const ENVELOPE = () => ({
+  panes: [{ id: 'pane-1', kind: 'coder', chatIds: [] as string[], activeChatIdx: 0 }],
+  tabNumbers: { 'chat-x': 3 },
+  nextTabNumber: 7,
+  closedPaneStack: [{ kind: 'coder', chatIds: ['old'], activeChatIdx: 0 }],
+});
+
+describe('resolveChatId — v2.6.5 WorkspaceState envelope', () => {
+  it('reads panes from the envelope without crashing (regression: panes.findIndex is not a function)', async () => {
+    const state: MockState = {
+      stored: ENVELOPE(),
+      existingChatOpen: false,
+      newChatId: 'new-chat-1',
+      inserted: false,
+    };
+    const chatId = await resolveChatId(mockSql(state), 'session-1', 'pane-1');
+    expect(chatId).toBe('new-chat-1');
+    expect(state.inserted).toBe(true);
+  });
+
+  it('preserves the envelope (tabNumbers/nextTabNumber/closedPaneStack) on write-back', async () => {
+    const state: MockState = {
+      stored: ENVELOPE(),
+      existingChatOpen: false,
+      newChatId: 'new-chat-1',
+      inserted: false,
+    };
+    await resolveChatId(mockSql(state), 'session-1', 'pane-1');
+    const w = state.written as Record<string, unknown>;
+    expect(Array.isArray(w.panes)).toBe(true); // envelope, not a bare array
+    expect(w.tabNumbers).toEqual({ 'chat-x': 3 });
+    expect(w.nextTabNumber).toBe(7);
+    expect(w.closedPaneStack).toEqual([{ kind: 'coder', chatIds: ['old'], activeChatIdx: 0 }]);
+  });
+
+  it('returns the existing open chat when the pane already has one', async () => {
+    const env = ENVELOPE();
+    env.panes[0]!.chatIds = ['existing-1'];
+    const state: MockState = {
+      stored: env,
+      existingChatOpen: true,
+      newChatId: 'should-not-be-used',
+      inserted: false,
+    };
+    const chatId = await resolveChatId(mockSql(state), 'session-1', 'pane-1');
+    expect(chatId).toBe('existing-1');
+    expect(state.inserted).toBe(false);
+  });
+
+  it('still accepts a legacy bare WorkspacePane[] array', async () => {
+    const state: MockState = {
+      stored: [{ id: 'pane-1', kind: 'coder', chatId: 'legacy-1', chatIds: ['legacy-1'], activeChatIdx: 0 }],
+      existingChatOpen: true,
+      newChatId: 'should-not-be-used',
+      inserted: false,
+    };
+    const chatId = await resolveChatId(mockSql(state), 'session-1', 'pane-1');
+    expect(chatId).toBe('legacy-1');
+    expect(state.inserted).toBe(false);
+  });
+});

apps/coder/src/routes/__tests__/providers.routes.test.ts

@@ -0,0 +1,211 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import Fastify, { type FastifyInstance } from 'fastify';
+import { existsSync, readFileSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { registerProviderRoutes } from '../providers.js';
+import { load } from '../../services/provider-config.js';
+import { loadProviderConfig } from '../../services/provider-config-registry.js';
+import { clearProviderSnapshotCache } from '../../services/provider-snapshot.js';
+import type { Config } from '../../config.js';
+import type { Sql } from '../../db.js';
+
+/** Minimal sql stub: available_agents reads return []. */
+function mockSql(): Sql {
+  return vi.fn((strings: TemplateStringsArray) => {
+    const q = strings.join('');
+    if (q.includes('available_agents')) return Promise.resolve([]);
+    return Promise.resolve([]);
+  }) as unknown as Sql;
+}
+
+let tmpCounter = 0;
+function freshPath(): string {
+  tmpCounter += 1;
+  return join(tmpdir(), `coder-providers-routes-${process.pid}-${tmpCounter}.json`);
+}
+
+function buildApp(providersPath: string): FastifyInstance {
+  const app = Fastify();
+  // Mirror index.ts: tolerate empty JSON bodies.
+  app.removeContentTypeParser(['application/json']);
+  app.addContentTypeParser('application/json', { parseAs: 'string' }, (_req, body, done) => {
+    const str = (body as string) ?? '';
+    if (str.trim().length === 0) return done(null, {});
+    try {
+      done(null, JSON.parse(str));
+    } catch (err) {
+      done(err as Error, undefined);
+    }
+  });
+  const config = {
+    CODER_PROVIDERS_PATH: providersPath,
+    LLAMA_SWAP_URL: 'http://llama-swap.test',
+    PROVIDER_PROBE_TTL_MS: 86_400_000,
+  } as unknown as Config;
+  registerProviderRoutes(app, mockSql(), config);
+  return app;
+}
+
+const JSON_HEADERS = { 'content-type': 'application/json' };
+const createdPaths: string[] = [];
+
+beforeEach(() => {
+  clearProviderSnapshotCache();
+  loadProviderConfig('/nonexistent-coder-providers.json'); // reset registry to built-ins
+  vi.restoreAllMocks();
+  vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('no network in test')));
+});
+
+afterEach(() => {
+  for (const p of createdPaths.splice(0)) {
+    try {
+      rmSync(p, { force: true });
+    } catch {
+      /* ignore */
+    }
+  }
+});
+
+describe('GET /api/providers/config', () => {
+  it('returns the current config file (built-ins-only when missing)', async () => {
+    const path = freshPath();
+    createdPaths.push(path);
+    const app = buildApp(path);
+    const res = await app.inject({ method: 'GET', url: '/api/providers/config' });
+    expect(res.statusCode).toBe(200);
+    expect(res.json()).toEqual({ providers: {} });
+    await app.close();
+  });
+
+  it('reflects an existing file', async () => {
+    const path = freshPath();
+    createdPaths.push(path);
+    writeFileSync(path, JSON.stringify({ providers: { goose: { enabled: false } } }));
+    const app = buildApp(path);
+    const res = await app.inject({ method: 'GET', url: '/api/providers/config' });
+    expect(res.json()).toEqual({ providers: { goose: { enabled: false } } });
+    await app.close();
+  });
+});
+
+describe('PATCH /api/providers/config', () => {
+  it('valid patch → 200, writes the merged file (order: validate→save→reload→clear)', async () => {
+    const path = freshPath();
+    createdPaths.push(path);
+    writeFileSync(path, JSON.stringify({ providers: { goose: { label: 'Goose' } } }));
+    const app = buildApp(path);
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/providers/config',
+      headers: JSON_HEADERS,
+      payload: JSON.stringify({ providers: { opencode: { enabled: false } } }),
+    });
+
+    expect(res.statusCode).toBe(200);
+    expect(res.json()).toMatchObject({ ok: true });
+    // File written + merged (goose untouched, opencode added).
+    const onDisk = load(path);
+    expect(onDisk.providers).toEqual({
+      goose: { label: 'Goose' },
+      opencode: { enabled: false },
+    });
+    await app.close();
+  });
+
+  it('null value deletes the override', async () => {
+    const path = freshPath();
+    createdPaths.push(path);
+    writeFileSync(path, JSON.stringify({ providers: { goose: { enabled: false }, opencode: { enabled: false } } }));
+    const app = buildApp(path);
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/providers/config',
+      headers: JSON_HEADERS,
+      payload: JSON.stringify({ providers: { goose: null } }),
+    });
+
+    expect(res.statusCode).toBe(200);
+    expect(load(path).providers).toEqual({ opencode: { enabled: false } });
+    await app.close();
+  });
+
+  it('INVALID body → 422 and the file is NOT written (validate before save)', async () => {
+    const path = freshPath();
+    createdPaths.push(path);
+    const before = JSON.stringify({ providers: { goose: { enabled: true } } });
+    writeFileSync(path, before);
+    const app = buildApp(path);
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/providers/config',
+      headers: JSON_HEADERS,
+      payload: JSON.stringify({ providers: { goose: { enabled: 'yes' } } }), // bad type
+    });
+
+    expect(res.statusCode).toBe(422);
+    // File must be byte-for-byte unchanged — nothing written on a 422.
+    expect(readFileSync(path, 'utf8')).toBe(before);
+    await app.close();
+  });
+
+  it('save failure → 500 and the file is NOT created (no state divergence)', async () => {
+    const path = join(tmpdir(), `no-such-dir-${process.pid}-${Date.now()}`, 'coder-providers.json');
+    const app = buildApp(path);
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/providers/config',
+      headers: JSON_HEADERS,
+      payload: JSON.stringify({ providers: { goose: { enabled: false } } }),
+    });
+
+    expect(res.statusCode).toBe(500);
+    expect(existsSync(path)).toBe(false);
+    await app.close();
+  });
+});
+
+describe('POST /api/providers/refresh', () => {
+  it('no body → refreshes all registered providers', async () => {
+    const app = buildApp(freshPath());
+    const res = await app.inject({ method: 'POST', url: '/api/providers/refresh' });
+    expect(res.statusCode).toBe(200);
+    expect(res.json().refreshed).toBeGreaterThan(0);
+    await app.close();
+  });
+
+  it('subset body → refreshed count reflects only the requested providers', async () => {
+    const app = buildApp(freshPath());
+    const res = await app.inject({
+      method: 'POST',
+      url: '/api/providers/refresh',
+      headers: JSON_HEADERS,
+      payload: JSON.stringify({ providers: ['boocode'] }),
+    });
+    expect(res.statusCode).toBe(200);
+    expect(res.json()).toEqual({ refreshed: 1 });
+    await app.close();
+  });
+});
+
+describe('GET /api/providers/:id/diagnostic', () => {
+  it('known provider → 200 JSON { diagnostic }', async () => {
+    const app = buildApp(freshPath());
+    const res = await app.inject({ method: 'GET', url: '/api/providers/boocode/diagnostic' });
+    expect(res.statusCode).toBe(200);
+    expect(res.headers['content-type']).toContain('application/json');
+    expect(res.json().diagnostic).toContain('provider: boocode');
+    await app.close();
+  });
+
+  it('unknown provider → 404', async () => {
+    const app = buildApp(freshPath());
+    const res = await app.inject({ method: 'GET', url: '/api/providers/nope/diagnostic' });
+    expect(res.statusCode).toBe(404);
+    await app.close();
+  });
+});

apps/coder/src/routes/__tests__/tasks-cancel.test.ts

@@ -0,0 +1,138 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import Fastify, { type FastifyInstance } from 'fastify';
+import postgres from 'postgres';
+import { registerTaskRoutes } from '../tasks.js';
+
+/**
+ * F1 — POST /api/tasks/:id/cancel route wiring.
+ *
+ * The route's job: reach the in-flight external run via `cancelExternal(taskId)`
+ * (the new abort hook), keep cancelling native inference for open chats unchanged,
+ * and land the task row in 'cancelled'. The streaming assistant message is
+ * finalized by the dispatcher's run-function, not here — that path is covered by
+ * finalize-message.test.ts. This suite pins the route's behavior against a real DB.
+ */
+describe.runIf(!!process.env.DATABASE_URL)('POST /api/tasks/:id/cancel (route, F1)', () => {
+  let sql: ReturnType<typeof postgres>;
+  let app: FastifyInstance;
+  let projectId: string;
+  let sessionId: string;
+  let chatId: string;
+
+  const externalCancelCalls: string[] = [];
+  const inferenceCancelCalls: Array<[string, string]> = [];
+  let externalReturns = true;
+
+  beforeAll(async () => {
+    sql = postgres(process.env.DATABASE_URL!, { max: 3 });
+    const serverSchema = resolve(__dirname, '../../../../server/src/schema.sql');
+    const coderSchema = resolve(__dirname, '../../schema.sql');
+    await sql.unsafe(readFileSync(serverSchema, 'utf8'));
+    await sql.unsafe(readFileSync(coderSchema, 'utf8'));
+
+    const [p] = await sql<{ id: string }[]>`
+      INSERT INTO projects (name, path, status) VALUES ('f1-cancel-route', '/tmp/f1-cancel-route', 'open') RETURNING id
+    `;
+    projectId = p!.id;
+    const [s] = await sql<{ id: string }[]>`
+      INSERT INTO sessions (project_id, name, model, status) VALUES (${projectId}, 'f1', 'm', 'open') RETURNING id
+    `;
+    sessionId = s!.id;
+    const [c] = await sql<{ id: string }[]>`
+      INSERT INTO chats (session_id, name, status) VALUES (${sessionId}, 'tab', 'open') RETURNING id
+    `;
+    chatId = c!.id;
+
+    app = Fastify();
+    registerTaskRoutes(
+      app,
+      sql,
+      {
+        cancel: async (sid: string, cid: string) => {
+          inferenceCancelCalls.push([sid, cid]);
+          return false;
+        },
+      },
+      (taskId: string) => {
+        externalCancelCalls.push(taskId);
+        return externalReturns;
+      },
+    );
+    await app.ready();
+  });
+
+  afterAll(async () => {
+    if (app) await app.close();
+    if (!sql) return;
+    await sql`DELETE FROM messages WHERE session_id = ${sessionId}`.catch(() => {});
+    await sql`DELETE FROM tasks WHERE project_id = ${projectId}`.catch(() => {});
+    await sql`DELETE FROM chats WHERE id = ${chatId}`.catch(() => {});
+    await sql`DELETE FROM sessions WHERE id = ${sessionId}`.catch(() => {});
+    await sql`DELETE FROM projects WHERE id = ${projectId}`.catch(() => {});
+    await sql.end({ timeout: 5 });
+  });
+
+  async function insertTask(agent: string | null, state: string): Promise<string> {
+    const [t] = await sql<{ id: string }[]>`
+      INSERT INTO tasks (project_id, input, agent, session_id, state, started_at)
+      VALUES (${projectId}, 'do a thing', ${agent}, ${sessionId}, ${state}, clock_timestamp())
+      RETURNING id
+    `;
+    return t!.id;
+  }
+
+  it('reaches cancelExternal and lands the task cancelled for a running external task', async () => {
+    externalReturns = true;
+    externalCancelCalls.length = 0;
+    const taskId = await insertTask('opencode', 'running');
+
+    const res = await app.inject({ method: 'POST', url: `/api/tasks/${taskId}/cancel` });
+    expect(res.statusCode).toBe(200);
+    expect(res.json()).toEqual({ cancelled: true });
+
+    expect(externalCancelCalls).toContain(taskId);
+
+    const [row] = await sql<{ state: string; ended_at: Date | null }[]>`
+      SELECT state, ended_at FROM tasks WHERE id = ${taskId}
+    `;
+    expect(row!.state).toBe('cancelled');
+    expect(row!.ended_at).not.toBeNull();
+  });
+
+  it('still cancels a native boocode task (cancelExternal returns false → inference.cancel path unchanged)', async () => {
+    externalReturns = false; // native task: no controller registered
+    externalCancelCalls.length = 0;
+    inferenceCancelCalls.length = 0;
+    const taskId = await insertTask(null, 'running');
+
+    const res = await app.inject({ method: 'POST', url: `/api/tasks/${taskId}/cancel` });
+    expect(res.statusCode).toBe(200);
+
+    // The route calls cancelExternal unconditionally (cheap, returns false here)...
+    expect(externalCancelCalls).toContain(taskId);
+    // ...and the native inference.cancel path still fires for the open chat.
+    expect(inferenceCancelCalls).toContainEqual([sessionId, chatId]);
+
+    const [row] = await sql<{ state: string }[]>`SELECT state FROM tasks WHERE id = ${taskId}`;
+    expect(row!.state).toBe('cancelled');
+  });
+
+  it('rejects cancelling an already-terminal task with 409 and never touches the abort hook', async () => {
+    externalCancelCalls.length = 0;
+    const taskId = await insertTask('opencode', 'completed');
+
+    const res = await app.inject({ method: 'POST', url: `/api/tasks/${taskId}/cancel` });
+    expect(res.statusCode).toBe(409);
+    expect(externalCancelCalls).not.toContain(taskId);
+  });
+
+  it('returns 404 for an unknown task', async () => {
+    const res = await app.inject({
+      method: 'POST',
+      url: `/api/tasks/00000000-0000-0000-0000-000000000000/cancel`,
+    });
+    expect(res.statusCode).toBe(404);
+  });
+});

apps/coder/src/routes/agent-sessions.ts

@@ -0,0 +1,59 @@
+import type { FastifyInstance } from 'fastify';
+import type { Sql } from '../db.js';
+
+// v2.6 Phase 1-UX (design §9b): chat-scoped "resumed vs new session" indicator.
+// `agent_sessions` is keyed (chat_id, agent) — the tab/chat is the agent-context
+// unit (P1.5-b). The route param is a SESSION id, so we resolve every chat in the
+// session and return the union of their agent_sessions rows. A session with two
+// opencode tabs yields two rows (one per chat); the frontend keys the chip per
+// chat, but the wire shape is a flat per-(chat,agent) list.
+//
+// has_session = agent_session_id IS NOT NULL — i.e. a native backend session id
+// (opencode/ACP) was created and stored, so switching back resumes rather than
+// starts fresh.
+export interface AgentSessionRow {
+  agent: string;
+  status: string;
+  has_session: boolean;
+  last_active_at: string | null;
+  // v2.6.8 per-(chat,agent) running token/cost totals (sampling-streamjson-tokens
+  // #8). BIGINT columns arrive as strings over the wire; the frontend coerces.
+  input_tokens: number;
+  output_tokens: number;
+  cost: number;
+}
+
+export function registerAgentSessionRoutes(app: FastifyInstance, sql: Sql): void {
+  // GET /api/sessions/:sessionId/agent-sessions — list the agent-session rows for
+  // every chat in the session (drives the AgentComposerBar resumed/new chip).
+  app.get<{ Params: { sessionId: string } }>(
+    '/api/sessions/:sessionId/agent-sessions',
+    async (req, reply) => {
+      const sessionId = req.params.sessionId;
+
+      const session = await sql<{ id: string }[]>`SELECT id FROM sessions WHERE id = ${sessionId}`;
+      if (session.length === 0) {
+        reply.code(404);
+        return { error: 'session not found' };
+      }
+
+      // Join through chats so the session-scoped param resolves to its (chat,agent)
+      // rows. last_active_at first → the frontend reads the freshest activity.
+      const rows = await sql<AgentSessionRow[]>`
+        SELECT
+          a.agent AS agent,
+          a.status AS status,
+          (a.agent_session_id IS NOT NULL) AS has_session,
+          a.last_active_at AS last_active_at,
+          a.input_tokens AS input_tokens,
+          a.output_tokens AS output_tokens,
+          a.cost AS cost
+        FROM agent_sessions a
+        JOIN chats c ON c.id = a.chat_id
+        WHERE c.session_id = ${sessionId}
+        ORDER BY a.last_active_at DESC NULLS LAST, a.agent ASC
+      `;
+      return rows;
+    },
+  );
+}

apps/coder/src/routes/chat-resolve.ts

@@ -8,6 +8,36 @@ interface WorkspacePaneRow {
   activeChatIdx?: number;
 }
 
+// v2.6.5: sessions.workspace_panes widened from a bare WorkspacePane[] to a
+// WorkspaceState envelope { panes, tabNumbers, nextTabNumber, closedPaneStack }.
+// (See the union validator in apps/server routes/sessions.ts + normalizeWorkspaceState
+// in apps/server read_tab_by_number.ts — this is the coder-side mirror.)
+interface WorkspaceStateRow {
+  panes: WorkspacePaneRow[];
+  tabNumbers: Record<string, number>;
+  nextTabNumber: number;
+  closedPaneStack: unknown[];
+}
+
+// MIGRATION: the stored value may be the legacy bare array OR the envelope.
+// Normalize to a full envelope so callers always read `.panes` as an array and
+// write the envelope back intact (preserving tabNumbers/nextTabNumber/closedPaneStack).
+export function normalizeWorkspaceState(v: unknown): WorkspaceStateRow {
+  if (Array.isArray(v)) {
+    return { panes: v as WorkspacePaneRow[], tabNumbers: {}, nextTabNumber: 1, closedPaneStack: [] };
+  }
+  if (v && typeof v === 'object' && Array.isArray((v as { panes?: unknown }).panes)) {
+    const env = v as Partial<WorkspaceStateRow>;
+    return {
+      panes: env.panes ?? [],
+      tabNumbers: env.tabNumbers ?? {},
+      nextTabNumber: env.nextTabNumber ?? 1,
+      closedPaneStack: env.closedPaneStack ?? [],
+    };
+  }
+  return { panes: [], tabNumbers: {}, nextTabNumber: 1, closedPaneStack: [] };
+}
+
 function chatNameForKind(kind: string): string {
   if (kind === 'coder' || kind === 'agent') return 'BooCoder';
   if (kind === 'terminal') return 'Terminal';
@@ -28,12 +58,13 @@ export async function resolveChatId(
   paneId: string,
 ): Promise<string | null> {
   return sql.begin(async (tx) => {
-    const sessionRows = await tx<{ workspace_panes: WorkspacePaneRow[] }[]>`
+    const sessionRows = await tx<{ workspace_panes: unknown }[]>`
       SELECT workspace_panes FROM sessions WHERE id = ${sessionId} FOR UPDATE
     `;
     if (sessionRows.length === 0) return null;
 
-    const panes = sessionRows[0]!.workspace_panes ?? [];
+    const state = normalizeWorkspaceState(sessionRows[0]!.workspace_panes);
+    const panes = state.panes;
     const paneIdx = panes.findIndex((p) => p.id === paneId);
     if (paneIdx < 0) return null;
 
@@ -69,9 +100,10 @@ export async function resolveChatId(
         : p,
     );
 
+    const nextState: WorkspaceStateRow = { ...state, panes: nextPanes };
     await tx`
       UPDATE sessions
-      SET workspace_panes = ${tx.json(nextPanes as never)},
+      SET workspace_panes = ${tx.json(nextState as never)},
           updated_at = clock_timestamp()
       WHERE id = ${sessionId}
     `;

apps/coder/src/routes/checkpoints.ts

@@ -0,0 +1,73 @@
+/**
+ * write-edit-robustness #4 — checkpoint restore + list routes (coder side).
+ *
+ * Proxied through the apps/server `/api/coder/*` blanket forwarder (no server-side
+ * change needed for new routes). Restore rewinds the session worktree to the
+ * checkpoint's shadow commit, trims the transcript from the anchor message forward,
+ * and resets the agent backend — see services/checkpoints.ts.
+ */
+import type { FastifyInstance } from 'fastify';
+import type { Sql } from '../db.js';
+import { restoreCheckpoint, CheckpointNotFoundError } from '../services/checkpoints.js';
+
+export function registerCheckpointRoutes(app: FastifyInstance, sql: Sql): void {
+  // GET /api/sessions/:sessionId/checkpoints?chat_id= — list a chat's checkpoints
+  // so the frontend can mark which messages have a restore point. When chat_id is
+  // omitted, returns every checkpoint for the session's chats.
+  app.get<{ Params: { sessionId: string }; Querystring: { chat_id?: string } }>(
+    '/api/sessions/:sessionId/checkpoints',
+    async (req, reply) => {
+      const sessionId = req.params.sessionId;
+      const chatId = req.query.chat_id;
+
+      const session = await sql<{ id: string }[]>`SELECT id FROM sessions WHERE id = ${sessionId}`;
+      if (session.length === 0) {
+        reply.code(404);
+        return { error: 'session not found' };
+      }
+
+      // Scope authoritatively through chats.session_id (always set) — NOT the
+      // denormalized checkpoints.session_id (nullable). The chat_id branch must
+      // still be session-gated or it's an IDOR (any session's chat_id reads its
+      // checkpoints).
+      const rows = chatId
+        ? await sql<{ id: string; chat_id: string; message_id: string | null; label: string | null; created_at: Date }[]>`
+            SELECT cp.id, cp.chat_id, cp.message_id, cp.label, cp.created_at
+            FROM checkpoints cp
+            JOIN chats c ON c.id = cp.chat_id
+            WHERE cp.chat_id = ${chatId} AND c.session_id = ${sessionId}
+            ORDER BY cp.created_at
+          `
+        : await sql<{ id: string; chat_id: string; message_id: string | null; label: string | null; created_at: Date }[]>`
+            SELECT cp.id, cp.chat_id, cp.message_id, cp.label, cp.created_at
+            FROM checkpoints cp
+            JOIN chats c ON c.id = cp.chat_id
+            WHERE c.session_id = ${sessionId}
+            ORDER BY cp.created_at
+          `;
+      return rows;
+    },
+  );
+
+  // POST /api/sessions/:sessionId/checkpoints/:checkpointId/restore — restore.
+  app.post<{ Params: { sessionId: string; checkpointId: string } }>(
+    '/api/sessions/:sessionId/checkpoints/:checkpointId/restore',
+    async (req, reply) => {
+      const { sessionId, checkpointId } = req.params;
+
+      try {
+        const result = await restoreCheckpoint(sql, checkpointId, {
+          sessionId,
+          log: app.log,
+        });
+        return result;
+      } catch (err) {
+        if (err instanceof CheckpointNotFoundError) {
+          reply.code(404);
+          return { error: err.message };
+        }
+        throw err;
+      }
+    },
+  );
+}

apps/coder/src/routes/lifecycle.ts

@@ -0,0 +1,122 @@
+/**
+ * v2.6 Phase 3 (3.3) — chat/session close-or-archive cleanup hook (coder side).
+ *
+ * Chat/session close + archive + delete all live in apps/server (Docker), which
+ * cannot see the host worktree dirs (/tmp/booworktrees), run git on them, or reach
+ * the warm agent processes the dispatcher pooled in THIS (host systemd) process. So
+ * — exactly like the `worktree-risk` guard — the server signals the coder when a
+ * chat/session closes, and the coder does the real teardown:
+ *   1. dispose the chat's warm-ACP backends (`agentPool.closeChat`) — kills the
+ *      goose/qwen child processes for that chat,
+ *   2. close the chat's opencode session on the shared server (`closeSession`),
+ *   3. mark every `agent_sessions` row for the chat 'closed' + (when the session's
+ *      last open chat closes) remove the shared session worktree, preflighting
+ *      work-at-risk so uncommitted/unmerged work is never silently dropped
+ *      (`closeChatBackendState`).
+ *
+ * Idempotent: closing an already-closed chat is a no-op (0 rows, no backend).
+ *
+ * SERVER WIRING (not done here — apps/server, out of this batch's scope): the
+ * server's `POST /api/chats/:id/archive`, `DELETE /api/chats/:id`, and the
+ * session archive/delete routes should fire-and-forget
+ *   fetch(`${BOOCODER_URL}/api/chats/${id}/close`, { method: 'POST' })
+ * after publishing their WS frame (best-effort; the orphan-worktree reaper +
+ * idle-pool eviction are the backstop if the call is missed).
+ */
+import type { FastifyInstance } from 'fastify';
+import type { Sql } from '../db.js';
+import { agentPool, OPENCODE_POOL_KEY } from '../services/agent-pool.js';
+import { closeChatBackendState } from '../services/worktrees.js';
+import type { AgentSessionHandle } from '../services/agent-backend.js';
+
+export function registerLifecycleRoutes(app: FastifyInstance, sql: Sql): void {
+  // POST /api/chats/:chatId/close — tear down all warm state for a chat tab.
+  app.post<{ Params: { chatId: string }; Querystring: { force?: string } }>(
+    '/api/chats/:chatId/close',
+    async (req) => {
+      const chatId = req.params.chatId;
+      const force = req.query.force === 'true' || req.query.force === '1';
+
+      // 1. Close the chat's opencode session on the SHARED server (the server is
+      //    not chat-keyed, so agentPool.closeChat won't touch it). Resolve the
+      //    stored opencode session id and ask the backend to drop it.
+      const ocRows = await sql<{ agent: string; agent_session_id: string | null; worktree_id: string | null; session_id: string | null }[]>`
+        SELECT agent, agent_session_id, worktree_id, session_id
+        FROM agent_sessions
+        WHERE chat_id = ${chatId} AND backend = 'opencode_server'
+      `;
+      const ocBackend = agentPool.peek(OPENCODE_POOL_KEY, 'opencode');
+      if (ocBackend) {
+        for (const row of ocRows) {
+          if (!row.agent_session_id) continue;
+          const handle: AgentSessionHandle = {
+            sessionId: row.session_id ?? '',
+            agent: row.agent,
+            backend: 'opencode_server',
+            chatId,
+            worktreeId: row.worktree_id ?? '',
+            agentSessionId: row.agent_session_id,
+            serverPort: null,
+          };
+          await ocBackend.closeSession(handle).catch((err) => {
+            app.log.warn({ err: err instanceof Error ? err.message : String(err), chatId }, 'lifecycle: opencode closeSession threw');
+          });
+        }
+      }
+
+      // 2. Dispose any warm-ACP backends pooled under this chat (kills the
+      //    goose/qwen child + marks its agent row closed via the backend).
+      const disposed = await agentPool.closeChat(chatId);
+
+      // 3. DB + worktree truth: mark agent rows closed; remove the shared session
+      //    worktree iff this was the session's last open chat (preflight at-risk).
+      const result = await closeChatBackendState(sql, chatId, { force });
+
+      app.log.info({ chatId, disposed, ...result }, 'lifecycle: chat closed');
+      return { ok: true, disposed, ...result };
+    },
+  );
+
+  // POST /api/sessions/:sessionId/close — close every open chat in a session
+  // (session archive/delete). Loops the chat-close path so the same preflight +
+  // teardown applies per chat; the worktree is removed on the last one.
+  app.post<{ Params: { sessionId: string }; Querystring: { force?: string } }>(
+    '/api/sessions/:sessionId/close',
+    async (req) => {
+      const sessionId = req.params.sessionId;
+      const force = req.query.force === 'true' || req.query.force === '1';
+
+      const chats = await sql<{ id: string }[]>`
+        SELECT id FROM chats WHERE session_id = ${sessionId}
+      `;
+      const results: { chatId: string; disposed: string[]; worktreeRemoved: boolean; worktreeAtRisk: boolean }[] = [];
+      for (const c of chats) {
+        const ocBackend = agentPool.peek(OPENCODE_POOL_KEY, 'opencode');
+        if (ocBackend) {
+          const ocRows = await sql<{ agent: string; agent_session_id: string | null; worktree_id: string | null; session_id: string | null }[]>`
+            SELECT agent, agent_session_id, worktree_id, session_id
+            FROM agent_sessions WHERE chat_id = ${c.id} AND backend = 'opencode_server'
+          `;
+          for (const row of ocRows) {
+            if (!row.agent_session_id) continue;
+            await ocBackend.closeSession({
+              sessionId: row.session_id ?? '',
+              agent: row.agent,
+              backend: 'opencode_server',
+              chatId: c.id,
+              worktreeId: row.worktree_id ?? '',
+              agentSessionId: row.agent_session_id,
+              serverPort: null,
+            }).catch(() => {});
+          }
+        }
+        const disposed = await agentPool.closeChat(c.id);
+        const r = await closeChatBackendState(sql, c.id, { force });
+        results.push({ chatId: c.id, disposed, worktreeRemoved: r.worktreeRemoved, worktreeAtRisk: r.worktreeAtRisk });
+      }
+
+      app.log.info({ sessionId, chats: results.length }, 'lifecycle: session closed');
+      return { ok: true, results };
+    },
+  );
+}

apps/coder/src/routes/messages.ts

@@ -2,7 +2,7 @@ import type { FastifyInstance } from 'fastify';
 import { z } from 'zod';
 import type { Sql } from '../db.js';
 import type { Broker } from '@boocode/server/broker';
-import type { WsFrame } from '@boocode/server/ws-frames';
+import type { WsFrame } from '@boocode/contracts/ws-frames';
 import { resolveChatId } from './chat-resolve.js';
 
 const AnswerUserInputBody = z.object({
@@ -53,6 +53,9 @@ interface MessageRow {
   role: string;
   content: string | null;
   status: string | null;
+  model: string | null;
+  ctx_used: number | null;
+  ctx_max: number | null;
   tool_calls: Array<{ id: string; name: string; args?: Record<string, unknown> }> | null;
   tool_results: {
     tool_call_id: string;
@@ -88,6 +91,9 @@ function mapCoderMessageRow(row: MessageRow) {
     role: row.role as 'user' | 'assistant' | 'system',
     content: row.content ?? '',
     status: (row.status ?? 'complete') as 'streaming' | 'complete' | 'failed',
+    ...(row.model ? { model: row.model } : {}),
+    ...(row.ctx_used != null ? { ctx_used: row.ctx_used } : {}),
+    ...(row.ctx_max != null ? { ctx_max: row.ctx_max } : {}),
     ...(reasoningText ? { reasoning_text: reasoningText } : {}),
     ...(tool_calls?.length ? { tool_calls } : {}),
   };
@@ -126,13 +132,13 @@ export function registerMessageRoutes(
 
       const rows = chatId
         ? await sql<MessageRow[]>`
-            SELECT id, role, content, status, tool_calls, tool_results, reasoning_parts
+            SELECT id, role, content, status, model, ctx_used, ctx_max, tool_calls, tool_results, reasoning_parts
             FROM messages_with_parts
             WHERE session_id = ${sessionId} AND chat_id = ${chatId}
             ORDER BY created_at ASC, id ASC
           `
         : await sql<MessageRow[]>`
-            SELECT id, role, content, status, tool_calls, tool_results, reasoning_parts
+            SELECT id, role, content, status, model, ctx_used, ctx_max, tool_calls, tool_results, reasoning_parts
             FROM messages_with_parts
             WHERE session_id = ${sessionId}
             ORDER BY created_at ASC, id ASC
@@ -224,8 +230,8 @@ export function registerMessageRoutes(
         // External provider: create a task for the dispatcher
         const projectId = sessionRows[0]!.project_id;
         const [task] = await sql<{ id: string; state: string }[]>`
-          INSERT INTO tasks (project_id, input, agent, model, mode_id, thinking_option_id, session_id)
-          VALUES (${projectId}, ${content}, ${provider}, ${model ?? null}, ${mode_id ?? null}, ${thinking_option_id ?? null}, ${sessionId})
+          INSERT INTO tasks (project_id, input, agent, model, mode_id, thinking_option_id, session_id, chat_id)
+          VALUES (${projectId}, ${content}, ${provider}, ${model ?? null}, ${mode_id ?? null}, ${thinking_option_id ?? null}, ${sessionId}, ${chatId})
           RETURNING id, state
         `;
         reply.code(202);

apps/coder/src/routes/pending.ts

@@ -1,4 +1,5 @@
 import type { FastifyInstance } from 'fastify';
+import { z } from 'zod';
 import type { Sql } from '../db.js';
 import {
   listPending,
@@ -6,7 +7,15 @@ import {
   applyAll,
   rejectOne,
   rewindOne,
+  queueCreate,
 } from '../services/pending_changes.js';
+import { WriteGuardError } from '../services/write_guard.js';
+import { rebaselineWorktreeAfterApply } from '../services/worktrees.js';
+
+const CreateBody = z.object({
+  file_path: z.string().min(1),
+  content: z.string(),
+});
 
 /**
  * Resolve project root from a session's project path.
@@ -51,6 +60,51 @@ export function registerPendingRoutes(app: FastifyInstance, sql: Sql): void {
     },
   );
 
+  // POST /api/sessions/:sessionId/pending/create — queue a new-file create
+  // (manual create from the RightRail file browser; no inference involved).
+  // queueCreate runs resolveWritePath internally, so a path that escapes the
+  // project root or hits a secret file throws WriteGuardError → 422 with the
+  // guard message. Mirrors the { error } 404 shape used by the other routes
+  // and the 422 status used by apply/rewind on failure.
+  app.post<{ Params: { sessionId: string } }>(
+    '/api/sessions/:sessionId/pending/create',
+    async (req, reply) => {
+      const sessionId = req.params.sessionId;
+
+      const parsed = CreateBody.safeParse(req.body);
+      if (!parsed.success) {
+        reply.code(400);
+        return { error: 'invalid body', details: parsed.error.flatten() };
+      }
+
+      const projectRoot = await resolveProjectRoot(sql, sessionId);
+      if (!projectRoot) {
+        reply.code(404);
+        return { error: 'session or project not found' };
+      }
+
+      try {
+        const change = await queueCreate(
+          sql,
+          sessionId,
+          null,
+          parsed.data.file_path,
+          parsed.data.content,
+          projectRoot,
+          // Manual RightRail create — no agent staged it; renders as "manual".
+          null,
+        );
+        return change;
+      } catch (err) {
+        if (err instanceof WriteGuardError) {
+          reply.code(422);
+          return { error: err.message };
+        }
+        throw err;
+      }
+    },
+  );
+
   // POST /api/sessions/:sessionId/pending/apply — apply all pending changes
   app.post<{ Params: { sessionId: string } }>(
     '/api/sessions/:sessionId/pending/apply',
@@ -64,6 +118,15 @@ export function registerPendingRoutes(app: FastifyInstance, sql: Sql): void {
       }
 
       const results = await applyAll(sql, sessionId, projectRoot);
+
+      // v2.6 Phase 3 (3.5): re-baseline the session worktree's diff to the applied
+      // state, so the next external-agent turn diffs against applied-not-original
+      // and doesn't re-surface the just-applied changes. Best-effort: a worktree
+      // session may not exist (native-only chat), and a re-baseline hiccup must not
+      // fail the apply the user just requested.
+      if (results.some((r) => r.success)) {
+        await rebaselineWorktreeAfterApply(sql, sessionId).catch(() => {});
+      }
       return { results };
     },
   );
@@ -83,6 +146,15 @@ export function registerPendingRoutes(app: FastifyInstance, sql: Sql): void {
       const result = await applyOne(sql, changeId, projectRoot);
       if (!result.success) {
         reply.code(422);
+      } else {
+        // v2.6 Phase 3 (3.5): re-baseline the session worktree after a successful
+        // apply so the next external-agent turn diffs against applied-not-original.
+        // Resolve the change's session; best-effort, never fails the apply.
+        const sessRows = await sql<{ session_id: string }[]>`
+          SELECT session_id FROM pending_changes WHERE id = ${changeId}
+        `;
+        const sessionId = sessRows[0]?.session_id;
+        if (sessionId) await rebaselineWorktreeAfterApply(sql, sessionId).catch(() => {});
       }
       return result;
     },

apps/coder/src/routes/providers.ts

@@ -1,7 +1,29 @@
 import type { FastifyInstance } from 'fastify';
+import { z } from 'zod';
 import type { Sql } from '../db.js';
 import type { Config } from '../config.js';
-import { getProviderSnapshot, clearProviderSnapshotCache } from '../services/provider-snapshot.js';
+import {
+  getProviderSnapshot,
+  clearProviderSnapshotCache,
+  peekSnapshotEntry,
+} from '../services/provider-snapshot.js';
+import {
+  load,
+  save,
+  CoderProvidersFileSchema,
+  ProviderConfigPatchSchema,
+  mergeProviderConfigPatch,
+} from '../services/provider-config.js';
+import {
+  reloadProviderConfig,
+  getResolvedRegistry,
+} from '../services/provider-config-registry.js';
+import {
+  getProviderDiagnostic,
+  type DiagnosticAgentRow,
+} from '../services/provider-diagnostic.js';
+
+const RefreshBodySchema = z.object({ providers: z.array(z.string()).optional() });
 
 export function registerProviderRoutes(app: FastifyInstance, sql: Sql, config: Config): void {
   app.get<{ Querystring: { cwd?: string } }>('/api/providers/snapshot', async (req, _reply) => {
@@ -9,9 +31,97 @@ export function registerProviderRoutes(app: FastifyInstance, sql: Sql, config: C
     return getProviderSnapshot(sql, config, cwd);
   });
 
-  app.post('/api/providers/refresh', async (_req, _reply) => {
+  // 4.1 — current loaded config file (raw CoderProvidersFile, not the resolved registry).
+  app.get('/api/providers/config', async (_req, _reply) => {
+    return load(config.CODER_PROVIDERS_PATH);
+  });
+
+  // 4.2 — patch the config file (design.md §6.2). Strict order is the whole
+  // correctness story: validate → save → reload → clear. A malformed body or an
+  // invalid merged result returns 422 and NEVER writes; a save failure returns
+  // 500 and leaves in-memory state untouched (no file/registry divergence).
+  app.patch('/api/providers/config', async (req, reply) => {
+    // 1. Validate the PATCH body shape (malformed → 422, never reaches merge).
+    const parsed = ProviderConfigPatchSchema.safeParse(req.body);
+    if (!parsed.success) {
+      return reply.code(422).send({
+        error: 'invalid provider config patch',
+        issues: parsed.error.flatten(),
+      });
+    }
+
+    // 2. Shallow per-id merge over the current file (null deletes; object replaces).
+    const current = load(config.CODER_PROVIDERS_PATH);
+    const merged = mergeProviderConfigPatch(current, parsed.data);
+
+    // 3. Validate the merged result — refuse to write a config that won't load.
+    const validated = CoderProvidersFileSchema.safeParse(merged);
+    if (!validated.success) {
+      return reply.code(422).send({
+        error: 'merged provider config is invalid',
+        issues: validated.error.flatten(),
+      });
+    }
+
+    // 4. Persist. If save throws, STOP here — do NOT reload/clear, so the file on
+    // disk and the in-memory resolved registry can never diverge.
+    try {
+      save(config.CODER_PROVIDERS_PATH, validated.data);
+    } catch (err) {
+      req.log.error(
+        { err: err instanceof Error ? err.message : String(err), path: config.CODER_PROVIDERS_PATH },
+        'provider-config: save failed — in-memory state untouched',
+      );
+      return reply.code(500).send({ error: 'failed to write provider config' });
+    }
+
+    // 5 + 6. Rebuild the in-memory resolved registry from the new file, then drop
+    // the snapshot cache so the next /snapshot reflects the change.
+    reloadProviderConfig();
+    clearProviderSnapshotCache();
+
+    // 7. Return the new config (per §6.2 `{ ok: true }`, plus the merged providers
+    // so the client can update without a follow-up GET).
+    return { ok: true, providers: validated.data.providers };
+  });
+
+  // 4.3 — force a cold probe. Optional { providers?: string[] } narrows the
+  // reported subset (design.md §6.3 Paseo pattern). The force=true snapshot is
+  // the only existing re-probe primitive (per-provider force would be a
+  // snapshot-internal change, out of Phase 4 scope), so the probe runs for all
+  // installed providers; the `refreshed` count reflects the requested subset.
+  app.post('/api/providers/refresh', async (req, reply) => {
+    const parsed = RefreshBodySchema.safeParse(req.body ?? {});
+    if (!parsed.success) {
+      return reply.code(422).send({ error: 'invalid refresh body', issues: parsed.error.flatten() });
+    }
+    const subset = parsed.data.providers;
     clearProviderSnapshotCache();
     const entries = await getProviderSnapshot(sql, config, undefined, true);
-    return { refreshed: entries.length };
+    const refreshed =
+      subset && subset.length > 0
+        ? entries.filter((e) => subset.includes(e.name)).length
+        : entries.length;
+    return { refreshed };
+  });
+
+  // 4.4 — per-provider diagnostic (design.md §6.4 → JSON `{ diagnostic: string }`).
+  // Read-only: reports cached state (resolved def + available_agents row + warm
+  // snapshot cache for the last probe error) plus a `which` PATH check. No probe
+  // spawn. The report itself is a plaintext block (§8); the route wraps it as JSON.
+  app.get<{ Params: { id: string } }>('/api/providers/:id/diagnostic', async (req, reply) => {
+    const id = req.params.id;
+    const resolved = getResolvedRegistry().get(id);
+    if (!resolved) {
+      return reply.code(404).send({ error: `unknown provider '${id}'` });
+    }
+    const rows = await sql<DiagnosticAgentRow[]>`
+      SELECT name, install_path, supports_acp, models, last_probed_at
+      FROM available_agents WHERE name = ${id}
+    `;
+    const report = await getProviderDiagnostic(resolved, rows[0], {
+      cachedEntry: peekSnapshotEntry(id),
+    });
+    return { diagnostic: report };
   });
 }

apps/coder/src/routes/skills.ts

@@ -2,7 +2,7 @@ import type { FastifyInstance } from 'fastify';
 import { z } from 'zod';
 import type { Sql } from '../db.js';
 import type { Broker } from '@boocode/server/broker';
-import type { WsFrame } from '@boocode/server/ws-frames';
+import type { WsFrame } from '@boocode/contracts/ws-frames';
 import { getSkillBody } from '@boocode/server/skills';
 import {
   buildSkillInvokeSyntheticFrames,
@@ -16,6 +16,12 @@ const SkillInvokeBody = z.object({
   pane_id: z.string().min(1).max(200),
   skill_name: z.string().min(1),
   user_message: z.string().max(64_000).nullable().optional(),
+  // v2.5.9: when set to an external provider, the skill runs UNDER that agent —
+  // its body is injected into a dispatched task instead of native inference.
+  provider: z.string().max(100).optional(),
+  model: z.string().max(200).optional(),
+  mode_id: z.string().max(200).optional(),
+  thinking_option_id: z.string().max(200).optional(),
 });
 
 interface InferenceApi {
@@ -39,9 +45,9 @@ export function registerSkillRoutes(
       }
 
       const sessionId = req.params.sessionId;
-      const { pane_id, skill_name } = parsed.data;
-      const sessionRows = await sql<{ id: string }[]>`
-        SELECT id FROM sessions WHERE id = ${sessionId}
+      const { pane_id, skill_name, provider, model, mode_id, thinking_option_id } = parsed.data;
+      const sessionRows = await sql<{ id: string; project_id: string }[]>`
+        SELECT id, project_id FROM sessions WHERE id = ${sessionId}
       `;
       if (sessionRows.length === 0) {
         reply.code(404);
@@ -69,6 +75,31 @@ export function registerSkillRoutes(
         return { error: 'unknown_skill', message: `unknown skill: ${skill_name}` };
       }
 
+      // v2.5.9: external agent → run the skill UNDER that agent. The skill body
+      // stays server-side (like the native path's tool message) and is injected
+      // into a dispatched task; the agent receives the skill instructions + the
+      // user's text. Mirrors the messages-route external-provider dispatch.
+      if (provider && provider !== 'boocode') {
+        const [userMsg] = await sql<{ id: string }[]>`
+          INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+          VALUES (${sessionId}, ${chatId}, 'user', ${userText}, 'complete', clock_timestamp())
+          RETURNING id
+        `;
+        broker.publishFrame(sessionId, { type: 'message_started', message_id: userMsg!.id, chat_id: chatId, role: 'user' } as WsFrame);
+        broker.publishFrame(sessionId, { type: 'delta', message_id: userMsg!.id, chat_id: chatId, content: userText } as WsFrame);
+        broker.publishFrame(sessionId, { type: 'message_complete', message_id: userMsg!.id, chat_id: chatId } as WsFrame);
+
+        const taskInput = `${body}\n\n---\n\n${userText}`;
+        const [task] = await sql<{ id: string; state: string }[]>`
+          INSERT INTO tasks (project_id, input, agent, model, mode_id, thinking_option_id, session_id, chat_id)
+          VALUES (${sessionRows[0]!.project_id}, ${taskInput}, ${provider}, ${model ?? null}, ${mode_id ?? null}, ${thinking_option_id ?? null}, ${sessionId}, ${chatId})
+          RETURNING id, state
+        `;
+        await sql`UPDATE chats SET updated_at = clock_timestamp() WHERE id = ${chatId}`;
+        reply.code(202);
+        return { user_message_id: userMsg!.id, task_id: task!.id, dispatched: true };
+      }
+
       const { result, toolCall } = await runSkillInvokeTransaction(sql, {
         sessionId,
         chatId,

apps/coder/src/routes/tasks.ts

@@ -8,6 +8,12 @@ interface InferenceApi {
   cancel: (sessionId: string, chatId: string) => Promise<boolean>;
 }
 
+// F1: the dispatcher's reach into an in-flight external-agent run. Narrow by
+// design (not the whole dispatcher) — the route only needs to fire the abort.
+// Returns true when a controller was registered for the task (an external run was
+// in flight), false otherwise (native boocode task, or already finished).
+export type ExternalCancelFn = (taskId: string) => boolean;
+
 const CreateBody = z.object({
   project_id: z.string().uuid(),
   input: z.string().min(1).max(64_000),
@@ -27,7 +33,12 @@ const ListQuery = z.object({
   project_id: z.string().uuid().optional(),
 });
 
-export function registerTaskRoutes(app: FastifyInstance, sql: Sql, inference: InferenceApi): void {
+export function registerTaskRoutes(
+  app: FastifyInstance,
+  sql: Sql,
+  inference: InferenceApi,
+  cancelExternal: ExternalCancelFn,
+): void {
   // POST /api/tasks — create a new task
   app.post('/api/tasks', async (req, reply) => {
     const parsed = CreateBody.safeParse(req.body);
@@ -95,7 +106,7 @@ export function registerTaskRoutes(app: FastifyInstance, sql: Sql, inference: In
   // GET /api/tasks/:id — single task detail
   app.get<{ Params: { id: string } }>('/api/tasks/:id', async (req, reply) => {
     const rows = await sql`
-      SELECT id, project_id, parent_task_id, state, input, output_summary, agent, model, execution_path, worktree_path, session_id, cost_tokens, started_at, ended_at, created_at
+      SELECT id, project_id, parent_task_id, state, input, output_summary, agent, model, execution_path, session_id, cost_tokens, started_at, ended_at, created_at
       FROM tasks
       WHERE id = ${req.params.id}
     `;
@@ -127,7 +138,14 @@ export function registerTaskRoutes(app: FastifyInstance, sql: Sql, inference: In
 
     cancelPendingPermission(taskId);
 
-    // If running, try to cancel inference
+    // F1: abort the in-flight external-agent run (opencode / goose / qwen / claude).
+    // Idempotent — a double-Stop re-aborts harmlessly; a native boocode task is not
+    // registered, so this returns false and the inference.cancel path below handles
+    // it unchanged. The dispatcher's run-function finalizes the streaming assistant
+    // message as 'cancelled' once the backend honors the signal.
+    cancelExternal(taskId);
+
+    // If running, try to cancel inference (native boocode path — unchanged).
     if ((task.state === 'running' || task.state === 'blocked') && task.session_id) {
       // Find active chat in the task's session
       const chats = await sql<{ id: string }[]>`

apps/coder/src/routes/worktree-safety.ts

@@ -0,0 +1,45 @@
+/**
+ * Session-delete work-loss guard (coder side).
+ *
+ * Session delete itself lives in apps/server (Docker), which CANNOT see the
+ * host worktree dirs (/tmp/booworktrees) or run git on them. Only BooCoder
+ * (host systemd) can. So the server's DELETE route calls these endpoints
+ * pre-delete to learn whether a session's worktree holds work at risk, and to
+ * stash it. The server owns the gate; coder owns the git truth.
+ */
+import type { FastifyInstance } from 'fastify';
+import type { Sql } from '../db.js';
+import { checkWorktreeWorkAtRisk, stashWorktree } from '../services/worktree-risk.js';
+
+export function registerWorktreeSafetyRoutes(app: FastifyInstance, sql: Sql): void {
+  // GET risk for a session's worktree(s). One row per session today (PK on
+  // session_id); the loop already handles the Phase-1.5 multi-worktree case.
+  app.get<{ Params: { sessionId: string } }>(
+    '/api/sessions/:sessionId/worktree-risk',
+    async (req) => {
+      const rows = await sql<{ worktree_path: string }[]>`
+        SELECT path AS worktree_path FROM worktrees WHERE session_id = ${req.params.sessionId}
+      `;
+      const reports = [];
+      for (const row of rows) {
+        reports.push(await checkWorktreeWorkAtRisk(row.worktree_path));
+      }
+      return { reports };
+    },
+  );
+
+  // Stash a session's worktree(s) — clears the dirty risk; recoverable.
+  app.post<{ Params: { sessionId: string } }>(
+    '/api/sessions/:sessionId/worktree-stash',
+    async (req) => {
+      const rows = await sql<{ worktree_path: string }[]>`
+        SELECT path AS worktree_path FROM worktrees WHERE session_id = ${req.params.sessionId}
+      `;
+      const results = [];
+      for (const row of rows) {
+        results.push({ worktreePath: row.worktree_path, ...(await stashWorktree(row.worktree_path)) });
+      }
+      return { results };
+    },
+  );
+}

apps/coder/src/routes/ws.ts

@@ -25,7 +25,7 @@ export function registerWebSocket(
 
       // Send snapshot of existing messages so client can hydrate
       const messages = await sql<Record<string, unknown>[]>`
-        SELECT id, session_id, chat_id, role, content, kind, tool_calls, tool_results, reasoning_parts, status, last_seq,
+        SELECT id, session_id, chat_id, role, content, kind, tool_calls, tool_results, reasoning_parts, status, model, last_seq,
                tokens_used, ctx_used, ctx_max, started_at, finished_at, created_at, metadata,
                summary, tail_start_id, compacted_at
         FROM messages_with_parts

apps/coder/src/schema.sql

@@ -25,7 +25,6 @@ CREATE TABLE IF NOT EXISTS tasks (
   agent TEXT,
   model TEXT,
   execution_path TEXT,
-  worktree_path TEXT,
   cost_tokens INTEGER,
   started_at TIMESTAMPTZ,
   ended_at TIMESTAMPTZ,
@@ -39,9 +38,9 @@ CREATE TABLE IF NOT EXISTS available_agents (
   install_path TEXT,
   version TEXT,
   supports_acp BOOLEAN NOT NULL DEFAULT false,
-  supports_mcp_client BOOLEAN NOT NULL DEFAULT false,
   last_probed_at TIMESTAMPTZ
 );
+ALTER TABLE available_agents DROP COLUMN IF EXISTS supports_mcp_client;
 
 -- v2.0.0 Phase 4: link tasks to their inference sessions.
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS session_id UUID REFERENCES sessions(id);
@@ -66,8 +65,226 @@ CREATE OR REPLACE VIEW human_inbox AS
 ALTER TABLE available_agents ADD COLUMN IF NOT EXISTS models JSONB DEFAULT '[]'::jsonb;
 ALTER TABLE available_agents ADD COLUMN IF NOT EXISTS label TEXT;
 ALTER TABLE available_agents ADD COLUMN IF NOT EXISTS transport TEXT DEFAULT 'pty';
+-- v2.5.10: persisted ACP available_commands (captured during the cold probe), so
+-- an agent's live command set survives the tier-2 probe skip and shows without a
+-- dispatch.
+ALTER TABLE available_agents ADD COLUMN IF NOT EXISTS commands JSONB DEFAULT '[]'::jsonb;
 
 -- v2.2.0: Paseo-style session config on tasks.
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS mode_id TEXT;
 ALTER TABLE tasks ADD COLUMN IF NOT EXISTS thinking_option_id TEXT;
-ALTER TABLE tasks ADD COLUMN IF NOT EXISTS feature_values JSONB;
+-- tasks.feature_values and tasks.worktree_path were never read or written by any
+-- code path; drop them from existing DBs (fresh DBs never had them in the CREATE).
+-- human_inbox is `SELECT *` over tasks, so it pins every task column — dropping a
+-- column while the view exists fails (2BP01). Drop the view, drop the columns, then
+-- recreate it with the current column set (idempotent on fresh + existing DBs).
+DROP VIEW IF EXISTS human_inbox;
+ALTER TABLE tasks DROP COLUMN IF EXISTS feature_values;
+ALTER TABLE tasks DROP COLUMN IF EXISTS worktree_path;
+CREATE OR REPLACE VIEW human_inbox AS
+  SELECT * FROM tasks WHERE state IN ('blocked', 'failed');
+
+-- v2.6: one backend session per (session, agent); resumed on switch-back.
+CREATE TABLE IF NOT EXISTS agent_sessions (
+  session_id UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
+  agent TEXT NOT NULL,
+  backend TEXT NOT NULL,
+  agent_session_id TEXT,
+  server_port INTEGER,
+  status TEXT NOT NULL DEFAULT 'idle',
+  last_active_at TIMESTAMPTZ,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
+  PRIMARY KEY (session_id, agent),
+  CONSTRAINT agent_sessions_backend_chk CHECK (backend IN ('opencode_server', 'acp_warm')),
+  CONSTRAINT agent_sessions_status_chk CHECK (status IN ('idle', 'active', 'crashed', 'closed'))
+);
+
+-- Migrate existing agent_sessions FK to CASCADE.
+DO $$ BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_constraint
+    WHERE conname = 'agent_sessions_session_id_fkey'
+      AND confdeltype <> 'c'
+  ) THEN
+    ALTER TABLE agent_sessions DROP CONSTRAINT agent_sessions_session_id_fkey;
+    ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_session_id_fkey
+      FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE CASCADE;
+  END IF;
+END $$;
+
+-- v2.6: config fingerprint for stale-session detection (auto-recover on model change).
+ALTER TABLE agent_sessions ADD COLUMN IF NOT EXISTS config_hash TEXT;
+
+-- v2.6 Phase 1-UX (U.6): opencode token/cost usage, ACCUMULATED per (chat_id, agent).
+-- opencode's warm server emits `session.next.step.ended` once per LLM step (several
+-- per multi-tool turn) carrying {tokens{input,output,reasoning,cache},cost}. We sum
+-- each step's normalized {input,output,cost} onto the session row — running totals
+-- for the whole conversation context, not last-step. Backend-only; no route/UI yet.
+-- input_tokens folds in cache read+write; output_tokens folds in reasoning (see
+-- backends/opencode-usage.ts). Defaults 0 so accumulation (col + delta) is well-defined.
+ALTER TABLE agent_sessions ADD COLUMN IF NOT EXISTS input_tokens BIGINT NOT NULL DEFAULT 0;
+ALTER TABLE agent_sessions ADD COLUMN IF NOT EXISTS output_tokens BIGINT NOT NULL DEFAULT 0;
+ALTER TABLE agent_sessions ADD COLUMN IF NOT EXISTS cost DOUBLE PRECISION NOT NULL DEFAULT 0;
+
+-- ─── P1.5-b (corrected): worktrees entity + re-key agent_sessions to (chat_id, agent) ───
+-- The TAB (a chat) is the context unit: two opencode tabs in one session = two
+-- independent contexts sharing one worktree. So agent_sessions keys on
+-- (chat_id, agent), NOT (worktree_id, agent) or (session_id, agent). The
+-- `worktrees` table is one-per-session (selectable later) and only referenced
+-- informationally by agent_sessions.worktree_id (SET NULL); chat_id is the key.
+--
+-- PREREQUISITE: the unmigratable test session (35 chats, 1 agent_sessions row that
+-- maps to no single chat) is DELETED before this runs, so agent_sessions is empty
+-- and the chat_id backfill is N/A. If a row with NULL chat_id remains, the verify
+-- gate below RAISEs and aborts — delete the offending session first.
+
+-- worktree as a first-class entity; survives session delete (session_id SET NULL).
+CREATE TABLE IF NOT EXISTS worktrees (
+  id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  session_id  UUID REFERENCES sessions(id) ON DELETE SET NULL,
+  project_id  UUID,
+  path        TEXT NOT NULL,
+  branch      TEXT,
+  base_commit TEXT,
+  slug        TEXT,
+  status      TEXT NOT NULL DEFAULT 'active' CHECK (status IN ('active','archived')),
+  created_at  TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+CREATE UNIQUE INDEX IF NOT EXISTS worktrees_active_path_uidx ON worktrees(path) WHERE status='active';
+
+-- session_worktrees was superseded by worktrees (v2.6/P1.5-b); all rows migrated
+-- before P2 cleanup. Drop the dead table; no-op on fresh DBs that never had it.
+DROP TABLE IF EXISTS session_worktrees;
+
+-- Dispatch hint: which chat (tab) a task belongs to. The coder message route and
+-- skills route set it from the frontend tab; session-less creators (arena, MCP,
+-- new_task, generic /api/tasks) leave it NULL and the dispatcher creates a chat.
+ALTER TABLE tasks ADD COLUMN IF NOT EXISTS chat_id UUID REFERENCES chats(id) ON DELETE SET NULL;
+
+-- Re-key columns on agent_sessions.
+ALTER TABLE agent_sessions ADD COLUMN IF NOT EXISTS chat_id UUID;
+ALTER TABLE agent_sessions ADD COLUMN IF NOT EXISTS worktree_id UUID;
+
+-- BACKFILL-VERIFY GATE: the new PK is (chat_id, agent), so chat_id must be
+-- non-null on every row before the swap. With the test session deleted this is a
+-- 0-row assertion; if any row has NULL chat_id (an unmigratable pre-existing row),
+-- abort loudly rather than create a degenerate (NULL, agent) key.
+DO $$
+DECLARE n int;
+BEGIN
+  SELECT count(*) INTO n FROM agent_sessions WHERE chat_id IS NULL;
+  IF n > 0 THEN
+    RAISE EXCEPTION 'P1.5-b: % agent_sessions row(s) have NULL chat_id — delete the unmigratable session(s) before applying', n;
+  END IF;
+END $$;
+
+-- Swap PK (session_id,agent) → (chat_id,agent) + FKs (run-once, guarded on the new
+-- FK's absence). chat_id CASCADEs from chats (closing a tab ends its context);
+-- worktree_id is informational SET NULL; session_id defanged to nullable SET NULL.
+DO $$ BEGIN
+  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'agent_sessions_chat_id_fkey') THEN
+    ALTER TABLE agent_sessions DROP CONSTRAINT IF EXISTS agent_sessions_pkey;
+    ALTER TABLE agent_sessions DROP CONSTRAINT IF EXISTS agent_sessions_session_id_fkey;
+    ALTER TABLE agent_sessions ALTER COLUMN session_id DROP NOT NULL;
+    ALTER TABLE agent_sessions ALTER COLUMN chat_id SET NOT NULL;
+    ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_pkey PRIMARY KEY (chat_id, agent);
+    ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_chat_id_fkey
+      FOREIGN KEY (chat_id) REFERENCES chats(id) ON DELETE CASCADE;
+    ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_session_id_fkey
+      FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE SET NULL;
+    ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_worktree_id_fkey
+      FOREIGN KEY (worktree_id) REFERENCES worktrees(id) ON DELETE SET NULL;
+  END IF;
+END $$;
+
+-- P1.5-b follow-up: converge agent_sessions.session_id FK CASCADE → SET NULL.
+-- The re-key block above re-adds session_id_fkey as SET NULL, but it is guarded on
+-- chat_id_fkey's ABSENCE — so a DB already re-keyed to (chat_id, agent) while
+-- session_id_fkey was still ON DELETE CASCADE never re-enters that block and stays
+-- 'c'. This standalone guard flips it to SET NULL ('n'), matching worktree_id.
+-- Idempotent (mirrors the session_worktrees defang's confdeltype check): only fires
+-- while the FK is still CASCADE — a no-op on a fresh deploy (already 'n' from the
+-- re-key block) and on every re-run thereafter.
+DO $$ BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_constraint
+    WHERE conname = 'agent_sessions_session_id_fkey'
+      AND confdeltype = 'c'
+  ) THEN
+    ALTER TABLE agent_sessions ALTER COLUMN session_id DROP NOT NULL;
+    ALTER TABLE agent_sessions DROP CONSTRAINT agent_sessions_session_id_fkey;
+    ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_session_id_fkey
+      FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE SET NULL;
+  END IF;
+END $$;
+
+-- v2.6: attribution for DiffPanel badges (Phase 1 UX reads this).
+ALTER TABLE pending_changes ADD COLUMN IF NOT EXISTS agent TEXT;
+
+-- write-edit-robustness #4: worktree checkpoints. A pre-turn shadow-commit of the
+-- session worktree (tracked + untracked, captured without disturbing the real
+-- index/working tree) stored in a private GC-safe ref refs/boocode/checkpoints/<id>.
+-- Created best-effort before each external-agent turn (opencode / warm-ACP / one-shot
+-- ACP+PTY); restore resets the worktree to commit_sha, trims the transcript from
+-- message_id forward, and resets the backend session. chat_id CASCADEs from chats
+-- (like agent_sessions); worktree_id SET NULL so a checkpoint outlives a reaped
+-- worktree row. session_id / message_id are informational (no FK — message rows are
+-- trimmed by a checkpoint restore and we must not block that on a dangling ref).
+CREATE TABLE IF NOT EXISTS checkpoints (
+  id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  chat_id     UUID NOT NULL REFERENCES chats(id) ON DELETE CASCADE,
+  session_id  UUID,
+  worktree_id UUID REFERENCES worktrees(id) ON DELETE SET NULL,
+  message_id  UUID,            -- anchor: the assistant turn row this checkpoint precedes
+  commit_sha  TEXT NOT NULL,   -- shadow-commit capturing the pre-turn worktree tree
+  label       TEXT,
+  created_at  TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+CREATE INDEX IF NOT EXISTS checkpoints_chat_created_idx ON checkpoints(chat_id, created_at);
+
+-- claude-sdk-sessionstore #9 (Part 1): append-only mirror of Claude Agent SDK
+-- session transcripts. The SDK's SessionStore adapter writes one JSONL line per
+-- entry; PostgresSessionStore (services/backends/claude-session-store.ts) inserts
+-- one row per entry and replays them ORDER BY id on resume. The store is generic
+-- per the SDK's SessionKey (project_key, session_id, subpath) — chat↔session
+-- ownership lives in agent_sessions, not here. subpath '' is the main transcript
+-- (the SDK's undefined subpath maps to '' in the column).
+CREATE TABLE IF NOT EXISTS claude_session_entries (
+  id          BIGSERIAL PRIMARY KEY,
+  project_key TEXT NOT NULL,
+  session_id  TEXT NOT NULL,
+  subpath     TEXT NOT NULL DEFAULT '',   -- '' = main transcript (SDK's undefined subpath maps here)
+  entry       JSONB NOT NULL,
+  created_at  TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+CREATE INDEX IF NOT EXISTS claude_session_entries_key_idx ON claude_session_entries (project_key, session_id, subpath, id);
+
+-- claude-sdk-sessionstore #9 (Part 2): the warm Claude-SDK backend persists its
+-- agent_sessions rows with backend='claude_sdk'. Widen the named CHECK to accept
+-- it. Idempotent: DROP the named constraint (the inline CREATE TABLE check above
+-- carries this explicit name, so DROP IF EXISTS targets it) + re-ADD the widened
+-- list. Re-runs/fresh deploys land on the same final constraint (the table-level
+-- CREATE already includes only the old two values on a fresh DB; this block then
+-- replaces it with the three-value list).
+ALTER TABLE agent_sessions DROP CONSTRAINT IF EXISTS agent_sessions_backend_chk;
+ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_backend_chk
+  CHECK (backend IN ('opencode_server', 'acp_warm', 'claude_sdk'));
+
+-- LISTEN/NOTIFY fast path: every tasks INSERT (from any call site — routes,
+-- new_task tool, arena, MCP server) fires pg_notify('tasks_new') in the same
+-- transaction, so the dispatcher reacts immediately instead of waiting for the
+-- fallback poll. Postgres holds the notification until COMMIT, so the listener
+-- always sees the committed row. A trigger covers all insert paths with no
+-- app-code drift. Idempotent: re-applied on every startup.
+CREATE OR REPLACE FUNCTION notify_tasks_new() RETURNS trigger AS $$
+BEGIN
+  PERFORM pg_notify('tasks_new', '');
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS tasks_notify_new ON tasks;
+CREATE TRIGGER tasks_notify_new
+  AFTER INSERT ON tasks
+  FOR EACH ROW
+  EXECUTE FUNCTION notify_tasks_new();

apps/coder/src/services/__tests__/acp-client-fs.test.ts

@@ -0,0 +1,50 @@
+import { describe, it, expect, afterEach } from 'vitest';
+import { mkdtempSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { readWorktreeTextFile, writeWorktreeTextFile } from '../acp-client-fs.js';
+
+const created: string[] = [];
+function freshWorktree(): string {
+  const wt = mkdtempSync(join(tmpdir(), 'acp-wt-'));
+  created.push(wt);
+  return wt;
+}
+afterEach(() => {
+  for (const d of created.splice(0)) {
+    try {
+      rmSync(d, { recursive: true, force: true });
+      rmSync(`${d}-evil`, { recursive: true, force: true });
+    } catch {
+      /* ignore */
+    }
+  }
+});
+
+describe('acp-client-fs worktree scoping', () => {
+  it('writes then reads a file inside the worktree', async () => {
+    const wt = freshWorktree();
+    await writeWorktreeTextFile(wt, 'sub/dir/note.txt', 'hello');
+    expect(await readWorktreeTextFile(wt, 'sub/dir/note.txt')).toBe('hello');
+  });
+
+  it('rejects ../ traversal on read', async () => {
+    const wt = freshWorktree();
+    await expect(readWorktreeTextFile(wt, '../../etc/passwd')).rejects.toThrow(/escapes worktree/);
+  });
+
+  it('rejects ../ traversal on write', async () => {
+    const wt = freshWorktree();
+    await expect(writeWorktreeTextFile(wt, '../escape.txt', 'x')).rejects.toThrow(/escapes worktree/);
+  });
+
+  it('rejects a sibling-prefix path (the unbounded-startsWith bug)', async () => {
+    const wt = freshWorktree();
+    // Absolute path that shares the worktree as a STRING prefix but is a sibling
+    // dir: `<wt>-evil/...`. A bare `startsWith(<wt>)` wrongly admits it.
+    await expect(readWorktreeTextFile(wt, `${wt}-evil/secret.txt`)).rejects.toThrow(/escapes worktree/);
+    await expect(writeWorktreeTextFile(wt, `${wt}-evil/secret.txt`, 'x')).rejects.toThrow(
+      /escapes worktree/,
+    );
+  });
+});

apps/coder/src/services/__tests__/acp-client.test.ts

@@ -0,0 +1,74 @@
+import { describe, it, expect, vi } from 'vitest';
+import type { RequestPermissionRequest, CreateElicitationRequest, SessionNotification } from '@agentclientprotocol/sdk';
+import { buildAcpClient, type AcpTurnContext } from '../acp-client.js';
+
+/**
+ * buildAcpClient (v2.7 audit reshape): the shared ACP `Client` closures. These
+ * tests cover the pure routing decisions that don't require the permission-waiter
+ * broker machinery — the auto-select/decline fallbacks and the between-turns drop.
+ */
+
+describe('buildAcpClient — sessionUpdate', () => {
+  it('drops the update when no turn is active (resolveTurn → null)', async () => {
+    const client = buildAcpClient('/wt', () => null);
+    // Must resolve without throwing and without an onSessionUpdate to call.
+    await expect(client.sessionUpdate({ sessionId: 's', update: {} } as unknown as SessionNotification)).resolves.toBeUndefined();
+  });
+
+  it('forwards the update to the active turn', async () => {
+    const onSessionUpdate = vi.fn();
+    const turn: AcpTurnContext = { taskId: 't', sessionId: 's', modeId: undefined, agent: 'goose', onSessionUpdate };
+    const client = buildAcpClient('/wt', () => turn);
+    const note = { sessionId: 's', update: {} } as unknown as SessionNotification;
+    await client.sessionUpdate(note);
+    expect(onSessionUpdate).toHaveBeenCalledWith(note);
+  });
+});
+
+describe('buildAcpClient — requestPermission fallback (no UI routing)', () => {
+  function req(options: Array<{ optionId: string }>): RequestPermissionRequest {
+    return { options } as unknown as RequestPermissionRequest;
+  }
+
+  it('auto-selects the first option when there is no turn', async () => {
+    const client = buildAcpClient('/wt', () => null);
+    const res = await client.requestPermission(req([{ optionId: 'allow' }, { optionId: 'deny' }]));
+    expect(res).toEqual({ outcome: { outcome: 'selected', optionId: 'allow' } });
+  });
+
+  it('cancels when there is no turn and no options', async () => {
+    const client = buildAcpClient('/wt', () => null);
+    const res = await client.requestPermission(req([]));
+    expect(res).toEqual({ outcome: { outcome: 'cancelled' } });
+  });
+
+  it('auto-selects when the turn has no taskId (UI routing gated off)', async () => {
+    const turn: AcpTurnContext = { taskId: undefined, sessionId: 's', modeId: undefined, agent: 'goose', onSessionUpdate: () => {} };
+    const client = buildAcpClient('/wt', () => turn);
+    const res = await client.requestPermission(req([{ optionId: 'ok' }]));
+    expect(res).toEqual({ outcome: { outcome: 'selected', optionId: 'ok' } });
+  });
+});
+
+describe('buildAcpClient — elicitation fallback', () => {
+  it('declines when there is no turn', async () => {
+    const client = buildAcpClient('/wt', () => null);
+    const res = await client.unstable_createElicitation!({} as CreateElicitationRequest);
+    expect(res).toEqual({ action: 'decline' });
+  });
+
+  it('declines when the turn has no taskId', async () => {
+    const turn: AcpTurnContext = { taskId: undefined, sessionId: 's', modeId: undefined, agent: 'goose', onSessionUpdate: () => {} };
+    const client = buildAcpClient('/wt', () => turn);
+    const res = await client.unstable_createElicitation!({} as CreateElicitationRequest);
+    expect(res).toEqual({ action: 'decline' });
+  });
+});
+
+describe('buildAcpClient — createTerminal', () => {
+  it('returns the noop terminal id', async () => {
+    const client = buildAcpClient('/wt', () => null);
+    const res = await client.createTerminal!({} as never);
+    expect(res).toEqual({ terminalId: 'noop' });
+  });
+});

apps/coder/src/services/__tests__/acp-event-map.test.ts

@@ -0,0 +1,110 @@
+import { describe, it, expect } from 'vitest';
+import type { SessionNotification } from '@agentclientprotocol/sdk';
+import { mapSessionUpdate } from '../acp-event-map.js';
+import type { AcpToolSnapshot } from '../acp-tool-snapshot.js';
+
+/**
+ * Pure event-mapping shared by the one-shot ACP dispatch (AcpStreamContext) and
+ * the warm ACP backend (Phase 2). Mirrors the original handleSessionUpdate switch
+ * verbatim but returns normalized AgentEvents instead of publishing broker frames.
+ */
+describe('mapSessionUpdate (shared ACP event mapping)', () => {
+  function note(update: SessionNotification['update']): SessionNotification {
+    return { sessionId: 's1', update };
+  }
+
+  it('maps an agent_message_chunk text → a text event', () => {
+    const events = mapSessionUpdate(
+      note({ sessionUpdate: 'agent_message_chunk', content: { type: 'text', text: 'hello' } }),
+    );
+    expect(events).toEqual([{ type: 'text', text: 'hello' }]);
+  });
+
+  it('maps an agent_thought_chunk text → a reasoning event', () => {
+    const events = mapSessionUpdate(
+      note({ sessionUpdate: 'agent_thought_chunk', content: { type: 'text', text: 'thinking' } }),
+    );
+    expect(events).toEqual([{ type: 'reasoning', text: 'thinking' }]);
+  });
+
+  it('ignores non-text content on message/thought chunks', () => {
+    const img = mapSessionUpdate(
+      note({
+        sessionUpdate: 'agent_message_chunk',
+        content: { type: 'image', data: 'x', mimeType: 'image/png' },
+      } as never),
+    );
+    expect(img).toEqual([]);
+  });
+
+  it('maps a tool_call → a tool_call event with a merged snapshot', () => {
+    const events = mapSessionUpdate(
+      note({
+        sessionUpdate: 'tool_call',
+        toolCallId: 't1',
+        title: 'read_file',
+        status: 'pending',
+        rawInput: { path: 'a.ts' },
+      } as never),
+    );
+    expect(events).toHaveLength(1);
+    expect(events[0]!.type).toBe('tool_call');
+    const snap = (events[0] as { type: 'tool_call'; toolCall: AcpToolSnapshot }).toolCall;
+    expect(snap.toolCallId).toBe('t1');
+    expect(snap.title).toBe('read_file');
+    expect(snap.status).toBe('pending');
+    expect(snap.rawInput).toEqual({ path: 'a.ts' });
+  });
+
+  it('maps a tool_call_update → a tool_update event merged over the prior snapshot', () => {
+    const prior = new Map<string, AcpToolSnapshot>([
+      ['t1', { toolCallId: 't1', title: 'read_file', status: 'pending', rawInput: { path: 'a.ts' } }],
+    ]);
+    const events = mapSessionUpdate(
+      note({
+        sessionUpdate: 'tool_call_update',
+        toolCallId: 't1',
+        status: 'completed',
+        rawOutput: 'file body',
+      } as never),
+      prior,
+    );
+    expect(events).toHaveLength(1);
+    expect(events[0]!.type).toBe('tool_update');
+    const snap = (events[0] as { type: 'tool_update'; toolCall: AcpToolSnapshot }).toolCall;
+    expect(snap.toolCallId).toBe('t1');
+    // merged: title carried from prior, status updated, output added, input retained
+    expect(snap.title).toBe('read_file');
+    expect(snap.status).toBe('completed');
+    expect(snap.rawOutput).toBe('file body');
+    expect(snap.rawInput).toEqual({ path: 'a.ts' });
+  });
+
+  it('maps available_commands_update → a commands event', () => {
+    const events = mapSessionUpdate(
+      note({
+        sessionUpdate: 'available_commands_update',
+        availableCommands: [
+          { name: 'plan', description: 'make a plan' },
+          { name: 'review', description: null },
+        ],
+      } as never),
+    );
+    expect(events).toEqual([
+      {
+        type: 'commands',
+        commands: [
+          { name: 'plan', description: 'make a plan' },
+          { name: 'review', description: undefined },
+        ],
+      },
+    ]);
+  });
+
+  it('returns [] for unhandled update kinds (plan, mode change)', () => {
+    expect(mapSessionUpdate(note({ sessionUpdate: 'plan', entries: [] } as never))).toEqual([]);
+    expect(
+      mapSessionUpdate(note({ sessionUpdate: 'current_mode_update', currentModeId: 'code' } as never)),
+    ).toEqual([]);
+  });
+});

apps/coder/src/services/__tests__/acp-spawn.test.ts

@@ -0,0 +1,73 @@
+import { describe, it, expect } from 'vitest';
+import { resolveLaunchSpec, resolveAcpSpawnArgs } from '../acp-spawn.js';
+import { buildResolvedRegistry } from '../provider-config-registry.js';
+import type { CoderProvidersFile } from '../provider-config.js';
+import { PROVIDERS } from '../provider-registry.js';
+
+/** Resolved def for a provider id under the given config (default: no override). */
+function builtin(name: string, providers: CoderProvidersFile['providers'] = {}) {
+  const def = buildResolvedRegistry(PROVIDERS, { providers }).get(name);
+  if (!def) throw new Error(`no resolved def for ${name}`);
+  return def;
+}
+
+describe('resolveLaunchSpec', () => {
+  // --- byte-identical built-in regression (the HARD CONSTRAINT) ---------------
+  // These argv values are the pre-v2.3 resolveAcpSpawnArgs switch outputs and
+  // MUST NOT change. spawn() is `spawn(spec.binary, spec.args, ...)`, so argv
+  // parity here is dispatch parity.
+  it('opencode (no override) → byte-identical argv ["acp"], binary = installPath', () => {
+    const spec = resolveLaunchSpec(builtin('opencode'), '/usr/bin/opencode');
+    expect(spec).not.toBeNull();
+    expect(spec!.args).toEqual(['acp']); // pre-v2.3 value
+    expect(spec!.binary).toBe('/usr/bin/opencode');
+    expect(spec!.env).toBeUndefined();
+    // cross-check against the switch source-of-truth
+    expect(spec!.args).toEqual(resolveAcpSpawnArgs('opencode'));
+  });
+
+  it('goose → ["acp"], qwen → ["--acp"] (byte-identical)', () => {
+    expect(resolveLaunchSpec(builtin('goose'), '/usr/bin/goose')!.args).toEqual(['acp']);
+    expect(resolveLaunchSpec(builtin('qwen'), '/usr/bin/qwen')!.args).toEqual(['--acp']);
+  });
+
+  it('built-in with null installPath falls back to the bare id (pre-v2.3 `installPath ?? agent`)', () => {
+    const spec = resolveLaunchSpec(builtin('opencode'), null);
+    expect(spec!.binary).toBe('opencode');
+    expect(spec!.args).toEqual(['acp']);
+  });
+
+  it('non-ACP / unknown provider → null (claude has no ACP argv)', () => {
+    expect(resolveLaunchSpec(builtin('claude'), '/usr/bin/claude')).toBeNull();
+    expect(resolveLaunchSpec(builtin('boocode'), null)).toBeNull();
+  });
+
+  // --- config-driven launch (the new capability) ------------------------------
+  it('custom ACP entry → configured command + env reach the spec', () => {
+    const def = builtin('amp-acp', {
+      'amp-acp': { extends: 'acp', label: 'Amp', command: ['amp-acp', '--acp'], env: { AMP_KEY: 'x' } },
+    });
+    const spec = resolveLaunchSpec(def, '/usr/local/bin/amp-acp');
+    expect(spec).not.toBeNull();
+    expect(spec!.binary).toBe('amp-acp'); // command[0], not the resolved install path
+    expect(spec!.args).toEqual(['--acp']); // command.slice(1)
+    expect(spec!.env).toEqual({ AMP_KEY: 'x' });
+  });
+
+  it('built-in WITH a config command override uses the override, not the switch default', () => {
+    const def = builtin('opencode', { opencode: { command: ['opencode', 'acp', '--verbose'], env: { DEBUG: '1' } } });
+    const spec = resolveLaunchSpec(def, '/usr/bin/opencode');
+    expect(spec!.binary).toBe('opencode');
+    expect(spec!.args).toEqual(['acp', '--verbose']);
+    expect(spec!.env).toEqual({ DEBUG: '1' });
+  });
+});
+
+describe('acp-dispatch spawn wiring (documented pass-through)', () => {
+  // dispatchViaAcp spawns `spawn(spec.binary, spec.args, { env: { ...process.env, ...spec.env } })`.
+  // The env merge layers config env over process.env; for a built-in with no
+  // config env, spec.env is undefined → { ...process.env } (byte-identical).
+  it('built-in with no config env yields an undefined spec.env (→ plain process.env at spawn)', () => {
+    expect(resolveLaunchSpec(builtin('opencode'), '/usr/bin/opencode')!.env).toBeUndefined();
+  });
+});

apps/coder/src/services/__tests__/agent-pool.test.ts

@@ -0,0 +1,233 @@
+import { describe, it, expect, vi } from 'vitest';
+import { AgentPool, OPENCODE_POOL_KEY } from '../agent-pool.js';
+import type {
+  AgentBackend,
+  AgentSessionHandle,
+  EnsureSessionOpts,
+  PromptCtx,
+  TurnResult,
+} from '../agent-backend.js';
+
+/**
+ * v2.6 Phase 3 — AgentPool lifecycle unit test (T.1). No DB / no child process:
+ * a fake AgentBackend records dispose + reports busy/health, so we exercise
+ * get-or-create, idle eviction, the LRU cap, the busy-never-evict rule, closeChat,
+ * and dispose-drains directly. The pure decisions are covered separately in
+ * backends/__tests__/lifecycle-decisions.test.ts; this verifies the wiring.
+ */
+
+class FakeBackend implements AgentBackend {
+  disposed = 0;
+  closedSessions = 0;
+  private busyFlag = false;
+  tickHealthCalls = 0;
+
+  constructor(public readonly name = 'fake') {}
+
+  setBusy(b: boolean): void {
+    this.busyFlag = b;
+  }
+
+  // — AgentBackend —
+  async ensureSession(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle> {
+    return {
+      sessionId,
+      agent: opts.agent,
+      backend: 'acp_warm',
+      chatId: opts.chatId,
+      worktreeId: opts.worktreeId,
+      agentSessionId: 'fake-session',
+      serverPort: null,
+    };
+  }
+  async prompt(_h: AgentSessionHandle, _input: string, _ctx: PromptCtx): Promise<TurnResult> {
+    return { ok: true };
+  }
+  async closeSession(): Promise<void> {
+    this.closedSessions++;
+  }
+  async dispose(): Promise<void> {
+    this.disposed++;
+  }
+  health(): 'up' | 'down' {
+    return 'up';
+  }
+  isBusy(): boolean {
+    return this.busyFlag;
+  }
+  async tickHealth(): Promise<void> {
+    this.tickHealthCalls++;
+  }
+}
+
+describe('AgentPool — get/register/touch (3.1)', () => {
+  it('register then get returns the same backend', () => {
+    const pool = new AgentPool();
+    const b = new FakeBackend();
+    pool.register('chat-1', 'goose', b);
+    expect(pool.get('chat-1', 'goose')).toBe(b);
+    expect(pool.get('chat-1', 'qwen')).toBeUndefined();
+  });
+
+  it('peek does NOT exist for a missing key', () => {
+    const pool = new AgentPool();
+    expect(pool.peek('nope', 'goose')).toBeUndefined();
+  });
+
+  it('health reports size + busy count', () => {
+    const pool = new AgentPool();
+    const a = new FakeBackend();
+    const b = new FakeBackend();
+    b.setBusy(true);
+    pool.register('c1', 'goose', a);
+    pool.register('c2', 'qwen', b);
+    expect(pool.health()).toEqual({ size: 2, busy: 1 });
+  });
+});
+
+describe('AgentPool.sweep — idle TTL eviction (3.1)', () => {
+  it('evicts an idle backend past the TTL and disposes it', async () => {
+    const pool = new AgentPool({ idleTtlMs: 1_000, maxLive: 100 });
+    const b = new FakeBackend();
+    pool.register('c1', 'goose', b);
+    // Sweep with now far past the registration → idle → evicted.
+    const { evicted } = await pool.sweep(Date.now() + 10_000);
+    expect(evicted).toEqual(['c1:goose']);
+    expect(b.disposed).toBe(1);
+    expect(pool.get('c1', 'goose')).toBeUndefined();
+  });
+
+  it('never evicts a busy backend even past the TTL', async () => {
+    const pool = new AgentPool({ idleTtlMs: 1_000, maxLive: 100 });
+    const b = new FakeBackend();
+    b.setBusy(true);
+    pool.register('c1', 'goose', b);
+    const { evicted } = await pool.sweep(Date.now() + 10_000);
+    expect(evicted).toEqual([]);
+    expect(b.disposed).toBe(0);
+    expect(pool.get('c1', 'goose')).toBe(b);
+  });
+
+  it('touch keeps a backend warm so the TTL measures from the last turn', async () => {
+    const pool = new AgentPool({ idleTtlMs: 5_000, maxLive: 100 });
+    const b = new FakeBackend();
+    pool.register('c1', 'goose', b);
+    const base = Date.now();
+    // 4s later, touch — resets activity. A sweep at +6s from base is only +2s from
+    // the touch → still within TTL → not evicted.
+    vi.spyOn(Date, 'now').mockReturnValue(base + 4_000);
+    pool.touch('c1', 'goose');
+    vi.restoreAllMocks();
+    const { evicted } = await pool.sweep(base + 6_000);
+    expect(evicted).toEqual([]);
+  });
+});
+
+describe('AgentPool.sweep — LRU cap (3.4)', () => {
+  it('evicts the least-recently-used beyond the cap', async () => {
+    const pool = new AgentPool({ idleTtlMs: 1_000_000, maxLive: 2 });
+    const base = 1_000_000;
+    const mk = (key: string, regAt: number) => {
+      vi.spyOn(Date, 'now').mockReturnValue(regAt);
+      const b = new FakeBackend(key);
+      const [chat, agent] = key.split(':');
+      pool.register(chat!, agent!, b);
+      vi.restoreAllMocks();
+      return b;
+    };
+    const a = mk('c1:goose', base + 100);
+    const b = mk('c2:goose', base + 300);
+    const c = mk('c3:goose', base + 200);
+    // 3 entries, cap 2, all within idle TTL → LRU (oldest = a@+100) evicted.
+    const { evicted } = await pool.sweep(base + 1_000);
+    expect(evicted).toEqual(['c1:goose']);
+    expect(a.disposed).toBe(1);
+    expect(b.disposed).toBe(0);
+    expect(c.disposed).toBe(0);
+  });
+});
+
+describe('AgentPool.sweep — proactive health probe (3.2)', () => {
+  it('drives each backend tickHealth before eviction', async () => {
+    const pool = new AgentPool({ idleTtlMs: 1_000_000, maxLive: 100 });
+    const b = new FakeBackend();
+    pool.register('c1', 'opencode', b);
+    await pool.sweep(Date.now());
+    expect(b.tickHealthCalls).toBe(1);
+  });
+});
+
+describe('AgentPool.closeChat — chat-close teardown (3.3)', () => {
+  it('disposes only the matching chat keys, leaving others + the shared server', async () => {
+    const pool = new AgentPool();
+    const goose = new FakeBackend('goose');
+    const qwen = new FakeBackend('qwen');
+    const other = new FakeBackend('other-chat');
+    const ocServer = new FakeBackend('opencode-server');
+    pool.register('chat-1', 'goose', goose);
+    pool.register('chat-1', 'qwen', qwen);
+    pool.register('chat-2', 'goose', other);
+    pool.register(OPENCODE_POOL_KEY, 'opencode', ocServer);
+
+    const removed = await pool.closeChat('chat-1');
+    expect(removed.sort()).toEqual(['chat-1:goose', 'chat-1:qwen']);
+    expect(goose.disposed).toBe(1);
+    expect(qwen.disposed).toBe(1);
+    // other chat + shared opencode server untouched.
+    expect(other.disposed).toBe(0);
+    expect(ocServer.disposed).toBe(0);
+    expect(pool.peek('chat-2', 'goose')).toBe(other);
+    expect(pool.peek(OPENCODE_POOL_KEY, 'opencode')).toBe(ocServer);
+  });
+
+  it('does not dispose a busy backend on closeChat', async () => {
+    const pool = new AgentPool();
+    const b = new FakeBackend();
+    b.setBusy(true);
+    pool.register('chat-1', 'goose', b);
+    const removed = await pool.closeChat('chat-1');
+    expect(removed).toEqual([]);
+    expect(b.disposed).toBe(0);
+  });
+
+  it('does not match a chat id that is a prefix of another', async () => {
+    // 'chat-1' must not match 'chat-10' — keys are `${chatId}:${agent}` so the
+    // colon delimiter prevents the prefix collision.
+    const pool = new AgentPool();
+    const a = new FakeBackend();
+    const b = new FakeBackend();
+    pool.register('chat-1', 'goose', a);
+    pool.register('chat-10', 'goose', b);
+    await pool.closeChat('chat-1');
+    expect(a.disposed).toBe(1);
+    expect(b.disposed).toBe(0);
+    expect(pool.peek('chat-10', 'goose')).toBe(b);
+  });
+});
+
+describe('AgentPool.dispose — drain all (T.1)', () => {
+  it('disposes every backend and clears the map', async () => {
+    const pool = new AgentPool();
+    const a = new FakeBackend();
+    const b = new FakeBackend();
+    pool.register('c1', 'goose', a);
+    pool.register('c2', 'qwen', b);
+    await pool.dispose();
+    expect(a.disposed).toBe(1);
+    expect(b.disposed).toBe(1);
+    expect(pool.health()).toEqual({ size: 0, busy: 0 });
+  });
+
+  it('tolerates a backend whose dispose throws', async () => {
+    const pool = new AgentPool();
+    const good = new FakeBackend();
+    const bad = new FakeBackend();
+    bad.dispose = async () => {
+      throw new Error('boom');
+    };
+    pool.register('c1', 'goose', bad);
+    pool.register('c2', 'qwen', good);
+    await expect(pool.dispose()).resolves.toBeUndefined();
+    expect(good.disposed).toBe(1);
+  });
+});

apps/coder/src/services/__tests__/cancel-registry.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, expect } from 'vitest';
+import { createCancelRegistry } from '../cancel-registry.js';
+
+/**
+ * F1 — per-task abort wiring. The registry is the missing link between the Stop
+ * route and the in-flight external run: register an AbortController per task id,
+ * cancel(taskId) aborts its signal, the run's .finally deletes it. Pure (no DB /
+ * child / IO) so the abort + idempotency contract is unit-testable in isolation.
+ */
+describe('CancelRegistry (F1 abort wiring)', () => {
+  it('register hands back a fresh controller; cancel aborts its signal', () => {
+    const reg = createCancelRegistry();
+    const ac = reg.register('t1');
+    expect(ac.signal.aborted).toBe(false);
+    expect(reg.has('t1')).toBe(true);
+
+    expect(reg.cancel('t1')).toBe(true);
+    expect(ac.signal.aborted).toBe(true);
+  });
+
+  it('cancel on an unknown task returns false (native task / cancel-before-register)', () => {
+    const reg = createCancelRegistry();
+    expect(reg.has('nope')).toBe(false);
+    expect(reg.cancel('nope')).toBe(false);
+  });
+
+  it('double-Stop is idempotent: a second cancel never throws and the signal stays aborted', () => {
+    const reg = createCancelRegistry();
+    const ac = reg.register('t1');
+
+    expect(reg.cancel('t1')).toBe(true);
+    // The run-function has not hit its .finally yet, so the entry is still
+    // present — a rapid second Stop re-aborts (abort() no-ops) without throwing.
+    expect(() => reg.cancel('t1')).not.toThrow();
+    expect(reg.cancel('t1')).toBe(true);
+    expect(ac.signal.aborted).toBe(true);
+  });
+
+  it('cancel after delete returns false (cancel-after-natural-exit is safe)', () => {
+    const reg = createCancelRegistry();
+    reg.register('t1');
+    reg.delete('t1');
+    expect(reg.has('t1')).toBe(false);
+    expect(reg.cancel('t1')).toBe(false);
+  });
+
+  it('delete of an unknown id is a no-op (never throws)', () => {
+    const reg = createCancelRegistry();
+    expect(() => reg.delete('ghost')).not.toThrow();
+  });
+});

apps/coder/src/services/__tests__/checkpoints.test.ts

@@ -0,0 +1,252 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { rm, mkdir } from 'node:fs/promises';
+import { resolve } from 'node:path';
+import postgres from 'postgres';
+import {
+  buildShadowCommitCommand,
+  createCheckpoint,
+  restoreCheckpoint,
+  CheckpointNotFoundError,
+} from '../checkpoints.js';
+import { ensureSessionWorktree } from '../worktrees.js';
+import { hostExec } from '../host-exec.js';
+
+/**
+ * write-edit-robustness #4 — worktree checkpoint tests.
+ *
+ * Pure-helper coverage (no DB / no host) for the shadow-commit command builder,
+ * plus a DB+git integration block (DB-opt-in via DATABASE_URL, skips cleanly
+ * otherwise; mirrors reconnect_integration.test.ts) that exercises the real
+ * create → restore round trip against a worktree on the host fs.
+ */
+
+describe('buildShadowCommitCommand (pure)', () => {
+  it('parks the commit under refs/boocode/checkpoints/<id> and prints only the SHA', () => {
+    const cmd = buildShadowCommitCommand('/tmp/booworktrees/sess-abc', 'cp-id-123');
+    // Uses a temp index so the real working tree/index is untouched.
+    expect(cmd).toContain('TMP=$(mktemp)');
+    expect(cmd).toContain('GIT_INDEX_FILE="$TMP" git read-tree HEAD');
+    expect(cmd).toContain('GIT_INDEX_FILE="$TMP" git add -A');
+    expect(cmd).toContain('git write-tree');
+    expect(cmd).toContain("git commit-tree \"$TREE\" -p HEAD -m \"boocode checkpoint\"");
+    // Ref name matches the row id, and stdout is ONLY the SHA (printf, no newline).
+    expect(cmd).toContain("update-ref 'refs/boocode/checkpoints/cp-id-123'");
+    expect(cmd).toContain("printf '%s' \"$SHA\"");
+    expect(cmd).not.toContain('echo "$SHA"');
+  });
+
+  it('shell-escapes the worktree path and the id', () => {
+    const cmd = buildShadowCommitCommand("/tmp/it's a path", "id'; rm -rf /");
+    // Single quotes inside the path/id are escaped via the '\'' wrapping idiom — no
+    // bare interpolation that could break out of the quoting.
+    expect(cmd).toContain("cd '/tmp/it'\\''s a path'");
+    expect(cmd).toContain("refs/boocode/checkpoints/id'\\''; rm -rf /");
+  });
+});
+
+describe.runIf(!!process.env.DATABASE_URL)('checkpoint create + restore (DB + git)', () => {
+  let sql: ReturnType<typeof postgres>;
+  const stamp = Date.now();
+  const projectDir = `/tmp/boocode-checkpoint-proj-${stamp}`;
+  let projectId: string;
+  let sessionId: string;
+  let chatId: string;
+  let worktreePath: string;
+
+  beforeAll(async () => {
+    sql = postgres(process.env.DATABASE_URL!, { max: 3 });
+
+    // Server schema first (FK targets), then coder schema (worktrees + checkpoints).
+    const serverSchema = resolve(__dirname, '../../../../server/src/schema.sql');
+    const coderSchema = resolve(__dirname, '../../schema.sql');
+    await sql.unsafe(readFileSync(serverSchema, 'utf8'));
+    await sql.unsafe(readFileSync(coderSchema, 'utf8'));
+
+    await mkdir(projectDir, { recursive: true });
+    await hostExec(
+      `cd ${projectDir} && git init -q && git config user.email t@t && git config user.name t ` +
+        `&& echo hello > README.md && git add -A && git commit -qm init`,
+      { timeoutMs: 20_000 },
+    );
+
+    const [project] = await sql<{ id: string }[]>`
+      INSERT INTO projects (name, path, status) VALUES ('checkpoint-test', ${projectDir}, 'open') RETURNING id
+    `;
+    projectId = project!.id;
+    const [session] = await sql<{ id: string }[]>`
+      INSERT INTO sessions (project_id, name, model, status)
+      VALUES (${projectId}, 'cp', 'm', 'open') RETURNING id
+    `;
+    sessionId = session!.id;
+    const [chat] = await sql<{ id: string }[]>`
+      INSERT INTO chats (session_id, name, status) VALUES (${sessionId}, 'tab', 'open') RETURNING id
+    `;
+    chatId = chat!.id;
+
+    const wt = await ensureSessionWorktree(sql, projectDir, sessionId);
+    worktreePath = wt.worktreePath;
+  });
+
+  afterAll(async () => {
+    if (sql) {
+      const rows = await sql<{ path: string }[]>`SELECT path FROM worktrees WHERE session_id = ${sessionId}`.catch(() => []);
+      for (const r of rows) {
+        await hostExec(`git -C ${projectDir} worktree remove ${r.path} --force`, { timeoutMs: 10_000 }).catch(() => {});
+      }
+      await sql`DELETE FROM checkpoints WHERE chat_id = ${chatId}`.catch(() => {});
+      await sql`DELETE FROM agent_sessions WHERE chat_id = ${chatId}`.catch(() => {});
+      await sql`DELETE FROM worktrees WHERE session_id = ${sessionId}`.catch(() => {});
+      await sql`DELETE FROM chats WHERE id = ${chatId}`.catch(() => {});
+      await sql`DELETE FROM sessions WHERE id = ${sessionId}`.catch(() => {});
+      await sql`DELETE FROM projects WHERE id = ${projectId}`.catch(() => {});
+      await sql.end({ timeout: 5 });
+    }
+    await rm(projectDir, { recursive: true, force: true });
+  });
+
+  it('createCheckpoint inserts a row + a private ref capturing tracked + untracked', async () => {
+    const [wt] = await sql<{ id: string }[]>`SELECT id FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'`;
+    const worktreeId = wt!.id;
+
+    // Pre-turn untracked + tracked-edit state the agent will start from.
+    await hostExec(`cd ${worktreePath} && echo edited >> README.md && echo new > extra.txt`, { timeoutMs: 10_000 });
+
+    const [assistantMsg] = await sql<{ id: string }[]>`
+      INSERT INTO messages (session_id, chat_id, role, content, status)
+      VALUES (${sessionId}, ${chatId}, 'assistant', '', 'streaming') RETURNING id
+    `;
+    const messageId = assistantMsg!.id;
+
+    const cp = await createCheckpoint(sql, {
+      chatId,
+      sessionId,
+      worktreeId,
+      worktreePath,
+      messageId,
+    });
+    expect(cp).not.toBeNull();
+    expect(cp!.commit_sha).toMatch(/^[0-9a-f]{40}$/);
+
+    const [row] = await sql<{ commit_sha: string; worktree_id: string; message_id: string }[]>`
+      SELECT commit_sha, worktree_id, message_id FROM checkpoints WHERE id = ${cp!.id}
+    `;
+    expect(row!.commit_sha).toBe(cp!.commit_sha);
+    expect(row!.worktree_id).toBe(worktreeId);
+    expect(row!.message_id).toBe(messageId);
+
+    // The ref exists and the captured tree carries the untracked file (proves the
+    // temp-index `git add -A` snapshotted untracked content).
+    const refLs = await hostExec(
+      `git -C ${worktreePath} ls-tree -r --name-only ${cp!.commit_sha}`,
+      { timeoutMs: 10_000 },
+    );
+    expect(refLs.exitCode).toBe(0);
+    expect(refLs.stdout).toContain('extra.txt');
+
+    // The shadow commit did NOT disturb the real working tree: extra.txt is still
+    // present + still untracked (status shows it).
+    const status = await hostExec(`git -C ${worktreePath} status --porcelain`, { timeoutMs: 10_000 });
+    expect(status.stdout).toContain('extra.txt');
+  });
+
+  it('restoreCheckpoint resets the worktree, trims the transcript, and drops later checkpoints', async () => {
+    // Clean slate for this test: reset the worktree to HEAD, clear prior rows.
+    await hostExec(`git -C ${worktreePath} reset --hard HEAD && git -C ${worktreePath} clean -fd`, { timeoutMs: 10_000 });
+    await sql`DELETE FROM checkpoints WHERE chat_id = ${chatId}`;
+    await sql`DELETE FROM messages WHERE chat_id = ${chatId}`;
+
+    const [wt] = await sql<{ id: string }[]>`SELECT id FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'`;
+    const worktreeId = wt!.id;
+
+    // Turn 1: a user msg, then the assistant turn the checkpoint anchors. The
+    // worktree is pristine (matches HEAD) when this checkpoint is captured.
+    await sql`INSERT INTO messages (session_id, chat_id, role, content, status) VALUES (${sessionId}, ${chatId}, 'user', 'do it', 'complete')`;
+    const [a1] = await sql<{ id: string }[]>`
+      INSERT INTO messages (session_id, chat_id, role, content, status)
+      VALUES (${sessionId}, ${chatId}, 'assistant', 'turn 1', 'complete') RETURNING id
+    `;
+    const cp1 = await createCheckpoint(sql, { chatId, sessionId, worktreeId, worktreePath, messageId: a1!.id });
+    expect(cp1).not.toBeNull();
+
+    // The agent (turn 1) writes a file into the worktree.
+    await hostExec(`cd ${worktreePath} && echo agent-wrote > agent.txt`, { timeoutMs: 10_000 });
+
+    // Turn 2: another user msg + assistant turn, AND a second (later) checkpoint.
+    await sql`INSERT INTO messages (session_id, chat_id, role, content, status) VALUES (${sessionId}, ${chatId}, 'user', 'more', 'complete')`;
+    const [a2] = await sql<{ id: string }[]>`
+      INSERT INTO messages (session_id, chat_id, role, content, status)
+      VALUES (${sessionId}, ${chatId}, 'assistant', 'turn 2', 'complete') RETURNING id
+    `;
+    const cp2 = await createCheckpoint(sql, { chatId, sessionId, worktreeId, worktreePath, messageId: a2!.id });
+    expect(cp2).not.toBeNull();
+
+    // An agent_sessions row that restore should mark 'crashed'.
+    await sql`
+      INSERT INTO agent_sessions (chat_id, session_id, worktree_id, agent, backend, agent_session_id, status, last_active_at)
+      VALUES (${chatId}, ${sessionId}, ${worktreeId}, 'goose', 'acp_warm', 'sess-1', 'active', clock_timestamp())
+      ON CONFLICT (chat_id, agent) DO UPDATE SET status = 'active'
+    `;
+
+    const before = await sql<{ id: string }[]>`SELECT id FROM messages WHERE chat_id = ${chatId} ORDER BY created_at`;
+    expect(before.length).toBe(4); // user, a1, user, a2
+
+    // Restore to cp1 (before turn 1's assistant message).
+    const result = await restoreCheckpoint(sql, cp1!.id, { sessionId });
+    expect(result.checkpoint_id).toBe(cp1!.id);
+    expect(result.worktree_reset).toBe(true);
+    expect(result.backend_reset).toBe(true);
+    // a1, user(turn2), a2 deleted (created_at >= a1) → 3 trimmed.
+    expect(result.messages_deleted).toBe(3);
+
+    // Transcript trimmed to just the first user message.
+    const after = await sql<{ role: string; content: string }[]>`SELECT role, content FROM messages WHERE chat_id = ${chatId} ORDER BY created_at`;
+    expect(after.length).toBe(1);
+    expect(after[0]!.role).toBe('user');
+
+    // Worktree reset: the agent's file is gone (it was written after cp1).
+    const ls = await hostExec(`ls ${worktreePath}/agent.txt`, { timeoutMs: 10_000 });
+    expect(ls.exitCode).not.toBe(0);
+
+    // The agent_sessions row was reset to 'crashed'.
+    const [as] = await sql<{ status: string }[]>`SELECT status FROM agent_sessions WHERE chat_id = ${chatId} AND agent = 'goose'`;
+    expect(as!.status).toBe('crashed');
+
+    // cp1 survives (re-restorable); cp2 (later) was dropped.
+    const cps = await sql<{ id: string }[]>`SELECT id FROM checkpoints WHERE chat_id = ${chatId}`;
+    expect(cps.map((c) => c.id)).toEqual([cp1!.id]);
+  });
+
+  it('restoreCheckpoint throws CheckpointNotFoundError for an unknown id', async () => {
+    await expect(
+      restoreCheckpoint(sql, '00000000-0000-0000-0000-000000000000', { sessionId }),
+    ).rejects.toBeInstanceOf(CheckpointNotFoundError);
+  });
+
+  it('restoreCheckpoint throws when the checkpoint is not in the requested session', async () => {
+    // A checkpoint whose session_id differs from the route's sessionId.
+    const [wt] = await sql<{ id: string }[]>`SELECT id FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'`;
+    const cp = await createCheckpoint(sql, { chatId, sessionId, worktreeId: wt!.id, worktreePath, messageId: null });
+    expect(cp).not.toBeNull();
+    await expect(
+      restoreCheckpoint(sql, cp!.id, { sessionId: '11111111-1111-1111-1111-111111111111' }),
+    ).rejects.toBeInstanceOf(CheckpointNotFoundError);
+    await sql`DELETE FROM checkpoints WHERE id = ${cp!.id}`;
+  });
+
+  it('restoreCheckpoint denies a NULL-session_id checkpoint from another session (no fail-open IDOR)', async () => {
+    // Regression for the fail-open authorization bug: a checkpoint row whose
+    // denormalized session_id is NULL must STILL be scoped via its chat's owning
+    // session (chats.session_id), not skipped. The old guard `cp.session_id &&
+    // cp.session_id !== sessionId` fell through on NULL → cross-session restore.
+    const [row] = await sql<{ id: string }[]>`
+      INSERT INTO checkpoints (chat_id, session_id, message_id, commit_sha)
+      VALUES (${chatId}, NULL, NULL, 'deadbeef')
+      RETURNING id
+    `;
+    await expect(
+      restoreCheckpoint(sql, row!.id, { sessionId: '22222222-2222-2222-2222-222222222222' }),
+    ).rejects.toBeInstanceOf(CheckpointNotFoundError);
+    await sql`DELETE FROM checkpoints WHERE id = ${row!.id}`;
+  });
+});

apps/coder/src/services/__tests__/cursor-models.test.ts

@@ -1,47 +0,0 @@
-import { describe, it, expect } from 'vitest';
-import { parseCursorAgentModelsOutput } from '../cursor-models.js';
-
-describe('parseCursorAgentModelsOutput', () => {
-  it('parses cursor-agent models output with default marker', () => {
-    const output = `
-Available models
-claude-4-sonnet - Claude 4 Sonnet (default)
-gpt-4.1 - GPT-4.1
-Tip: use cursor-agent models for full list
-`.trim();
-
-    const models = parseCursorAgentModelsOutput(output);
-
-    expect(models).toEqual([
-      { id: 'claude-4-sonnet', label: 'Claude 4 Sonnet', isDefault: true },
-      { id: 'gpt-4.1', label: 'GPT-4.1', isDefault: false },
-    ]);
-  });
-
-  it('uses current marker when no default', () => {
-    const output = `
-model-a - Model A (current)
-model-b - Model B
-`.trim();
-
-    const models = parseCursorAgentModelsOutput(output);
-
-    expect(models.find((m) => m.id === 'model-a')?.isDefault).toBe(true);
-    expect(models.find((m) => m.id === 'model-b')?.isDefault).toBe(false);
-  });
-
-  it('defaults to first model when no markers', () => {
-    const output = 'alpha - Alpha\nbeta - Beta';
-    const models = parseCursorAgentModelsOutput(output);
-
-    expect(models[0]?.isDefault).toBe(true);
-    expect(models[1]?.isDefault).toBe(false);
-  });
-
-  it('skips malformed lines', () => {
-    const output = 'no-separator\nvalid - Valid';
-    const models = parseCursorAgentModelsOutput(output);
-
-    expect(models).toEqual([{ id: 'valid', label: 'Valid', isDefault: true }]);
-  });
-});

apps/coder/src/services/__tests__/dcp-strip.test.ts

@@ -0,0 +1,73 @@
+import { describe, it, expect } from 'vitest';
+import { stripDcpTags, makeDcpStreamStripper } from '../dcp-strip.js';
+
+// Feed chunks through a fresh stripper and return the fully reassembled output
+// (everything emitted during streaming + the final flush) — i.e. what the
+// dispatcher would accumulate into the persisted message content.
+function run(chunks: string[]): string {
+  const s = makeDcpStreamStripper();
+  let out = '';
+  for (const c of chunks) out += s.push(c);
+  out += s.flush();
+  return out;
+}
+
+describe('stripDcpTags (one-shot)', () => {
+  it('removes a complete tag', () => {
+    expect(stripDcpTags('Yes — "Test".\n\n<dcp-message-id>m0019</dcp-message-id>')).toBe(
+      'Yes — "Test".\n\n',
+    );
+  });
+  it('leaves text without a tag untouched', () => {
+    expect(stripDcpTags('no tag here')).toBe('no tag here');
+  });
+});
+
+describe('per-chunk strip is INSUFFICIENT (documents the bug)', () => {
+  it('a tag split across chunks survives a naive per-chunk .replace()', () => {
+    const chunks = ['Yes.\n\n<dcp', '-message', '-id>m0019</dcp', '-message-id>'];
+    const naive = chunks.map(stripDcpTags).join('');
+    // The reassembled content still contains the tag — this is the screenshot bug.
+    expect(naive).toContain('<dcp-message-id>m0019</dcp-message-id>');
+  });
+});
+
+describe('makeDcpStreamStripper (cross-chunk fix)', () => {
+  it('strips a tag split across chunks (the real opencode case)', () => {
+    expect(run(['Yes.\n\n<dcp', '-message', '-id>m0019</dcp', '-message-id>'])).toBe('Yes.\n\n');
+  });
+
+  it('strips a tag split at EVERY character boundary', () => {
+    const full = 'Answer.<dcp-message-id>m0019</dcp-message-id>';
+    expect(run([...full])).toBe('Answer.');
+  });
+
+  it('strips a tag delivered whole in one chunk', () => {
+    expect(run(['Answer.<dcp-message-id>m0019</dcp-message-id>'])).toBe('Answer.');
+  });
+
+  it('passes through text with no tag', () => {
+    expect(run(['hello ', 'world'])).toBe('hello world');
+  });
+
+  it('does NOT swallow legitimate < content (code/HTML/generics)', () => {
+    expect(run(['use ', '<div>', ' and ', 'Array<', 'string>'])).toBe('use <div> and Array<string>');
+  });
+
+  it('handles a lone < that is not a dcp tag, split across chunks', () => {
+    expect(run(['a <', 'b c'])).toBe('a <b c');
+  });
+
+  it('emits surrounding text and strips a mid-text tag', () => {
+    expect(run(['before ', '<dcp-message-id>', 'm1', '</dcp-message-id>', ' after'])).toBe(
+      'before  after',
+    );
+  });
+
+  it('flushes a truncated/never-closed partial tag without leaking it as a complete tag', () => {
+    // If the stream ends mid-tag, flush strips complete tags; an incomplete
+    // remnant is returned as-is (no complete tag ever existed to render).
+    const out = run(['done.<dcp-message-id>m00']);
+    expect(out).not.toContain('</dcp-message-id>');
+  });
+});

apps/coder/src/services/__tests__/finalize-message.test.ts

@@ -0,0 +1,163 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import postgres from 'postgres';
+import type { WsFrame } from '@boocode/contracts/ws-frames';
+import { classifyTerminalStatus, finalizeStreamingMessage } from '../finalize-message.js';
+
+/**
+ * F1 (D-7 / OCE-001 / OCE-002) — finalizing a Stop'd or errored external turn.
+ *
+ * `classifyTerminalStatus` is the pure D-7 decision (user Stop / AbortError →
+ * cancelled, genuine error → failed). `finalizeStreamingMessage` writes that
+ * terminal state onto the streaming assistant row and publishes the matching
+ * message_complete frame — idempotently, guarded by `WHERE status='streaming'`,
+ * so a double-Stop or an abort-then-catch settles the message exactly once and
+ * never clobbers a row that already finished cleanly.
+ */
+describe('classifyTerminalStatus (pure, D-7)', () => {
+  it('maps a fired abort signal to cancelled (user Stop)', () => {
+    expect(classifyTerminalStatus({ aborted: true })).toBe('cancelled');
+  });
+
+  it('maps a thrown AbortError to cancelled', () => {
+    const e = new Error('the operation was aborted');
+    e.name = 'AbortError';
+    expect(classifyTerminalStatus({ aborted: false, error: e })).toBe('cancelled');
+  });
+
+  it('maps a genuine thrown error to failed', () => {
+    expect(classifyTerminalStatus({ aborted: false, error: new Error('boom') })).toBe('failed');
+  });
+
+  it('defaults a no-abort / no-error catch to failed', () => {
+    expect(classifyTerminalStatus({ aborted: false })).toBe('failed');
+  });
+});
+
+describe.runIf(!!process.env.DATABASE_URL)('finalizeStreamingMessage (DB)', () => {
+  let sql: ReturnType<typeof postgres>;
+  let projectId: string;
+  let sessionId: string;
+  let chatId: string;
+
+  beforeAll(async () => {
+    sql = postgres(process.env.DATABASE_URL!, { max: 3 });
+    // Server schema owns messages/sessions/chats (FK targets); coder schema after.
+    const serverSchema = resolve(__dirname, '../../../../server/src/schema.sql');
+    const coderSchema = resolve(__dirname, '../../schema.sql');
+    await sql.unsafe(readFileSync(serverSchema, 'utf8'));
+    await sql.unsafe(readFileSync(coderSchema, 'utf8'));
+
+    const [p] = await sql<{ id: string }[]>`
+      INSERT INTO projects (name, path, status) VALUES ('f1-finalize', '/tmp/f1-finalize', 'open') RETURNING id
+    `;
+    projectId = p!.id;
+    const [s] = await sql<{ id: string }[]>`
+      INSERT INTO sessions (project_id, name, model, status) VALUES (${projectId}, 'f1', 'm', 'open') RETURNING id
+    `;
+    sessionId = s!.id;
+    const [c] = await sql<{ id: string }[]>`
+      INSERT INTO chats (session_id, name, status) VALUES (${sessionId}, 'tab', 'open') RETURNING id
+    `;
+    chatId = c!.id;
+  });
+
+  afterAll(async () => {
+    if (!sql) return;
+    await sql`DELETE FROM messages WHERE session_id = ${sessionId}`.catch(() => {});
+    await sql`DELETE FROM chats WHERE id = ${chatId}`.catch(() => {});
+    await sql`DELETE FROM sessions WHERE id = ${sessionId}`.catch(() => {});
+    await sql`DELETE FROM projects WHERE id = ${projectId}`.catch(() => {});
+    await sql.end({ timeout: 5 });
+  });
+
+  async function insertStreaming(): Promise<string> {
+    const [m] = await sql<{ id: string }[]>`
+      INSERT INTO messages (session_id, chat_id, role, content, status)
+      VALUES (${sessionId}, ${chatId}, 'assistant', '', 'streaming') RETURNING id
+    `;
+    return m!.id;
+  }
+
+  it('finalizes a streaming row to cancelled, persists partial content, publishes one frame', async () => {
+    const id = await insertStreaming();
+    const frames: WsFrame[] = [];
+    const did = await finalizeStreamingMessage(sql, (_s, f) => frames.push(f), {
+      sessionId,
+      chatId,
+      assistantId: id,
+      status: 'cancelled',
+      model: 'qwen',
+      content: 'partial answer',
+    });
+
+    expect(did).toBe(true);
+    const [row] = await sql<{ status: string; content: string; finished_at: Date | null }[]>`
+      SELECT status, content, finished_at FROM messages WHERE id = ${id}
+    `;
+    expect(row!.status).toBe('cancelled');
+    expect(row!.content).toBe('partial answer');
+    expect(row!.finished_at).not.toBeNull();
+    expect(frames).toHaveLength(1);
+    expect(frames[0]!.type).toBe('message_complete');
+    expect((frames[0] as { status?: string }).status).toBe('cancelled');
+  });
+
+  it('is idempotent for a double-Stop: second call updates nothing and re-publishes nothing', async () => {
+    const id = await insertStreaming();
+    const frames: WsFrame[] = [];
+    const push = (_s: string, f: WsFrame): void => {
+      frames.push(f);
+    };
+
+    expect(
+      await finalizeStreamingMessage(sql, push, { sessionId, chatId, assistantId: id, status: 'cancelled', model: null }),
+    ).toBe(true);
+    expect(
+      await finalizeStreamingMessage(sql, push, { sessionId, chatId, assistantId: id, status: 'cancelled', model: null }),
+    ).toBe(false);
+
+    expect(frames).toHaveLength(1);
+    const [row] = await sql<{ status: string }[]>`SELECT status FROM messages WHERE id = ${id}`;
+    expect(row!.status).toBe('cancelled');
+  });
+
+  it('never clobbers a row that already finished cleanly (abort raced a clean finish)', async () => {
+    const [m] = await sql<{ id: string }[]>`
+      INSERT INTO messages (session_id, chat_id, role, content, status)
+      VALUES (${sessionId}, ${chatId}, 'assistant', 'done', 'complete') RETURNING id
+    `;
+    const id = m!.id;
+    const frames: WsFrame[] = [];
+
+    const did = await finalizeStreamingMessage(sql, (_s, f) => frames.push(f), {
+      sessionId,
+      chatId,
+      assistantId: id,
+      status: 'cancelled',
+      model: null,
+    });
+
+    expect(did).toBe(false);
+    expect(frames).toHaveLength(0);
+    const [row] = await sql<{ status: string; content: string }[]>`
+      SELECT status, content FROM messages WHERE id = ${id}
+    `;
+    expect(row!.status).toBe('complete');
+    expect(row!.content).toBe('done');
+  });
+
+  it('no-ops on an empty assistantId (throw happened before the row was created)', async () => {
+    const frames: WsFrame[] = [];
+    const did = await finalizeStreamingMessage(sql, (_s, f) => frames.push(f), {
+      sessionId,
+      chatId,
+      assistantId: '',
+      status: 'failed',
+      model: null,
+    });
+    expect(did).toBe(false);
+    expect(frames).toHaveLength(0);
+  });
+});

apps/coder/src/services/__tests__/frame-emitter.test.ts

@@ -0,0 +1,102 @@
+import { describe, it, expect } from 'vitest';
+import type { Broker } from '@boocode/server/broker';
+import { makeFrameEmitter } from '../frame-emitter.js';
+import { makeDcpStreamStripper } from '../dcp-strip.js';
+import type { AcpToolSnapshot } from '../acp-tool-snapshot.js';
+
+/**
+ * makeFrameEmitter (v2.7 audit reshape): the AgentEvent → WS-frame mapping + turn
+ * accumulators extracted from AcpStreamContext. Pure-ish over an injected broker.
+ */
+
+function fakeBroker(): { broker: Broker; frames: Array<{ sid: string; frame: Record<string, unknown> }> } {
+  const frames: Array<{ sid: string; frame: Record<string, unknown> }> = [];
+  const broker = {
+    publishFrame: (sid: string, frame: unknown) => {
+      frames.push({ sid, frame: frame as Record<string, unknown> });
+    },
+  } as unknown as Broker;
+  return { broker, frames };
+}
+
+const toolSnap: AcpToolSnapshot = { toolCallId: 'c1', title: 'grep', status: 'completed', rawOutput: 'x' };
+
+describe('makeFrameEmitter — streaming frames', () => {
+  it('maps text/reasoning/tool events to delta/reasoning_delta/tool_call frames', () => {
+    const { broker, frames } = fakeBroker();
+    const em = makeFrameEmitter({ broker, sessionId: 's1', chatId: 'ch1', assistantId: 'm1' });
+
+    em.onEvent({ type: 'text', text: 'hello ' });
+    em.onEvent({ type: 'reasoning', text: 'mulling' });
+    em.onEvent({ type: 'tool_call', toolCall: toolSnap });
+
+    expect(frames.map((f) => f.frame.type)).toEqual(['delta', 'reasoning_delta', 'tool_call']);
+    expect(frames[0]!.frame).toMatchObject({ message_id: 'm1', chat_id: 'ch1', content: 'hello ' });
+    expect(frames[2]!.frame).toMatchObject({ message_id: 'm1', chat_id: 'ch1' });
+    expect(em.output).toBe('hello ');
+    expect(em.reasoningText).toBe('mulling');
+    expect(em.snapshots).toHaveLength(1);
+  });
+
+  it('publishes a tool_call frame for BOTH tool_call and tool_update events', () => {
+    const { broker, frames } = fakeBroker();
+    const em = makeFrameEmitter({ broker, sessionId: 's1', chatId: 'ch1', assistantId: 'm1' });
+    em.onEvent({ type: 'tool_update', toolCall: toolSnap });
+    expect(frames).toHaveLength(1);
+    expect(frames[0]!.frame.type).toBe('tool_call');
+  });
+
+  it('publishes an agent_commands frame and merges the command cache', () => {
+    const { broker, frames } = fakeBroker();
+    const taskId = `task-fe-${Math.floor(performance.now())}-${frames.length}`;
+    const em = makeFrameEmitter({ broker, sessionId: 's1', chatId: 'ch1', assistantId: 'm1', taskId });
+    em.onEvent({ type: 'commands', commands: [{ name: 'plan' }] });
+    expect(frames).toHaveLength(1);
+    expect(frames[0]!.frame).toMatchObject({ type: 'agent_commands', task_id: taskId, session_id: 's1' });
+  });
+
+  it('does not publish a commands frame without a taskId', () => {
+    const { broker, frames } = fakeBroker();
+    const em = makeFrameEmitter({ broker, sessionId: 's1', chatId: 'ch1', assistantId: 'm1' });
+    em.onEvent({ type: 'commands', commands: [{ name: 'plan' }] });
+    expect(frames).toHaveLength(0);
+  });
+});
+
+describe('makeFrameEmitter — no broker (one-shot accumulation)', () => {
+  it('accumulates output/reasoning/snapshots but publishes nothing', () => {
+    const em = makeFrameEmitter({ sessionId: 's1', chatId: 'ch1', assistantId: 'm1' });
+    em.onEvent({ type: 'text', text: 'abc' });
+    em.onEvent({ type: 'reasoning', text: 'r' });
+    em.onEvent({ type: 'tool_call', toolCall: toolSnap });
+    expect(em.output).toBe('abc');
+    expect(em.reasoningText).toBe('r');
+    expect(em.snapshots).toHaveLength(1);
+  });
+});
+
+describe('makeFrameEmitter — dcp stripping (opencode path contract)', () => {
+  it('strips a split dcp tag across deltas and flushes the tail on finalize', () => {
+    const { broker, frames } = fakeBroker();
+    const em = makeFrameEmitter({ broker, sessionId: 's1', chatId: 'ch1', assistantId: 'm1', dcp: makeDcpStreamStripper() });
+
+    for (const chunk of ['Answer.', '<dcp', '-message', '-id>m1</dcp', '-message-id>', ' tail']) {
+      em.onEvent({ type: 'text', text: chunk });
+    }
+    em.finalize();
+
+    expect(em.output).toBe('Answer. tail');
+    const published = frames.filter((f) => f.frame.type === 'delta').map((f) => f.frame.content).join('');
+    expect(published).toBe('Answer. tail');
+  });
+
+  it('finalize is a no-op without a dcp stripper', () => {
+    const { broker, frames } = fakeBroker();
+    const em = makeFrameEmitter({ broker, sessionId: 's1', chatId: 'ch1', assistantId: 'm1' });
+    em.onEvent({ type: 'text', text: 'raw <dcp-message-id>m</dcp-message-id>' });
+    em.finalize();
+    // No stripping without a stripper — verbatim text (prior ACP-path behavior).
+    expect(em.output).toBe('raw <dcp-message-id>m</dcp-message-id>');
+    expect(frames).toHaveLength(1);
+  });
+});

apps/coder/src/services/__tests__/fuzzy-match.test.ts

@@ -0,0 +1,173 @@
+import { describe, it, expect } from 'vitest';
+import { locateMatch, SIMILARITY_THRESHOLD } from '../fuzzy-match.js';
+
+// Helper: assert a resolved span and slice it back out of the content so the
+// test pins the EXACT file text the caller would replace.
+function span(result: ReturnType<typeof locateMatch>): { start: number; end: number } {
+  if (result.kind !== 'exact' && result.kind !== 'fuzzy') {
+    throw new Error(`expected a located span, got ${result.kind}`);
+  }
+  return { start: result.start, end: result.end };
+}
+
+describe('locateMatch — strategy 1: exact', () => {
+  it('returns an exact unique span', () => {
+    const content = 'alpha\nbeta\ngamma\n';
+    const result = locateMatch(content, 'beta');
+    expect(result.kind).toBe('exact');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('beta');
+  });
+
+  it('returns the right offsets for a multi-line exact needle', () => {
+    const content = 'one\ntwo\nthree\nfour\n';
+    const needle = 'two\nthree';
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('exact');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe(needle);
+  });
+
+  it('refuses when the exact needle occurs more than once', () => {
+    const content = 'foo\nbar\nfoo\nbar\nfoo\n';
+    const result = locateMatch(content, 'foo');
+    expect(result).toEqual({ kind: 'ambiguous', count: 3 });
+  });
+});
+
+describe('locateMatch — strategy 2: per-line whitespace', () => {
+  it('matches across trailing-whitespace drift at the real span', () => {
+    // File has trailing spaces the model dropped from a TWO-line copy. A
+    // single-line needle would be located by exact indexOf (it's a substring),
+    // so use two lines where line 1's trailing ws breaks an exact substring run.
+    const content = 'function f() {\n  setup();   \n  return 1;\n}\n';
+    const needle = '  setup();\n  return 1;'; // line 1 missing trailing spaces
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    // The returned span covers the ORIGINAL lines including the trailing spaces.
+    expect(content.slice(start, end)).toBe('  setup();   \n  return 1;');
+  });
+
+  it('matches across indentation drift (multi-line block)', () => {
+    // File indents with 4 spaces; model emitted 2-space indentation. trimEnd
+    // alone does not normalize LEADING whitespace, so this exercises... actually
+    // leading-indent drift is a Levenshtein-tier fallback. Here we keep the
+    // leading indent identical and drift only trailing whitespace per line.
+    const content = ['if (x) {', '    doThing();    ', '    doOther();', '}'].join('\n');
+    const needle = ['    doThing();', '    doOther();'].join('\n');
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('    doThing();    \n    doOther();');
+  });
+
+  it('ignores leading/trailing blank needle lines', () => {
+    const content = 'header\nbody line\nfooter\n';
+    const needle = '\n\nbody line\n\n';
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('body line');
+  });
+
+  it('reports ambiguous when a whitespace-window matches twice', () => {
+    // Both line 1 and line 4 differ from the needle only by trailing whitespace,
+    // so exact indexOf fails (no exact substring) and the whitespace tier finds
+    // two equivalent windows → ambiguous.
+    const content = 'x = 1;  \ny = 2;\nz = 3;\nx = 1;\t\n';
+    const needle = 'x = 1;'; // no trailing ws → not an exact substring of either line
+    const result = locateMatch(content, needle);
+    expect(result).toEqual({ kind: 'ambiguous', count: 2 });
+  });
+});
+
+describe('locateMatch — strategy 3: unicode canonicalization', () => {
+  it('matches across curly quotes', () => {
+    const content = "const s = 'hello';\n";
+    const needle = 'const s = ‘hello’;'; // ‘hello’
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    // Span maps back to ORIGINAL (straight-quote) text.
+    expect(content.slice(start, end)).toBe("const s = 'hello';");
+  });
+
+  it('matches across curly double-quotes', () => {
+    const content = 'log("done");\n';
+    const needle = 'log(“done”);'; // “done”
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('log("done");');
+  });
+
+  it('matches across an em-dash drift', () => {
+    const content = 'range 1-10 inclusive\n';
+    const needle = 'range 1—10 inclusive'; // em-dash
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('range 1-10 inclusive');
+  });
+
+  it('matches across a non-breaking space drift', () => {
+    const content = 'a b c\n'; // plain spaces
+    const needle = 'a b c'; // nbsp between words
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('a b c');
+  });
+});
+
+describe('locateMatch — strategy 4: Levenshtein', () => {
+  it('matches a >= threshold near-miss (small typo drift)', () => {
+    // Needle has a one-char typo ('totals' vs 'total') so it is NOT an exact
+    // substring and the whitespace/canonical tiers (which require equality) both
+    // miss; Levenshtein similarity stays well above the 0.66 floor.
+    const content = 'const total = sum + tax;\n';
+    const needle = 'const totals = sum + tax;';
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    // Span maps to the real (correctly-spelled) file line.
+    expect(content.slice(start, end)).toBe('const total = sum + tax;');
+  });
+
+  it('matches a multi-line block with indentation drift via Levenshtein', () => {
+    const content = ['function g() {', '  return compute(a, b);', '}'].join('\n');
+    // 6-space indent vs file's 2-space; trimEnd does not fix leading indent, so
+    // this lands on the Levenshtein tier (joined-trim makes it identical → ~1.0).
+    const needle = ['      return compute(a, b);'].join('\n');
+    const result = locateMatch(content, needle);
+    expect(result.kind).toBe('fuzzy');
+    const { start, end } = span(result);
+    expect(content.slice(start, end)).toBe('  return compute(a, b);');
+  });
+
+  it('returns not_found for a below-threshold miss', () => {
+    const content = 'the quick brown fox jumps over the lazy dog\n';
+    const needle = 'completely unrelated string of text here xyz';
+    const result = locateMatch(content, needle);
+    expect(result).toEqual({ kind: 'not_found' });
+  });
+
+  it('returns not_found for a genuinely-absent needle', () => {
+    const content = 'alpha\nbeta\ngamma\n';
+    const needle = 'this content does not exist anywhere at all';
+    const result = locateMatch(content, needle);
+    expect(result).toEqual({ kind: 'not_found' });
+  });
+});
+
+describe('locateMatch — edge cases', () => {
+  it('returns not_found for an empty needle', () => {
+    expect(locateMatch('anything', '')).toEqual({ kind: 'not_found' });
+  });
+
+  it('exposes a sane similarity threshold', () => {
+    expect(SIMILARITY_THRESHOLD).toBeGreaterThan(0);
+    expect(SIMILARITY_THRESHOLD).toBeLessThanOrEqual(1);
+  });
+});

apps/coder/src/services/__tests__/provider-commands.test.ts

@@ -3,7 +3,7 @@ import { getManifestCommands, mergeCommands, PROVIDER_COMMANDS } from '../provid
 
 describe('provider-commands', () => {
   it('defines commands for every external harness', () => {
-    for (const name of ['claude', 'opencode', 'cursor', 'goose', 'qwen', 'copilot']) {
+    for (const name of ['claude', 'opencode', 'goose', 'qwen']) {
       expect(getManifestCommands(name).length, name).toBeGreaterThan(0);
     }
   });

apps/coder/src/services/__tests__/provider-config-registry.test.ts

@@ -0,0 +1,93 @@
+import { describe, it, expect, vi } from 'vitest';
+import { buildResolvedRegistry } from '../provider-config-registry.js';
+import { PROVIDERS } from '../provider-registry.js';
+import type { CoderProvidersFile } from '../provider-config.js';
+
+describe('buildResolvedRegistry', () => {
+  it('applies a built-in override (goose label)', () => {
+    const config: CoderProvidersFile = { providers: { goose: { label: 'Goosey' } } };
+    const reg = buildResolvedRegistry(PROVIDERS, config);
+    const goose = reg.get('goose');
+    expect(goose).toBeDefined();
+    expect(goose!.label).toBe('Goosey');
+    expect(goose!.configLabel).toBe('Goosey');
+    expect(goose!.enabled).toBe(true);
+    expect(goose!.isBuiltin).toBe(true);
+    expect(goose!.isCustomAcp).toBe(false);
+  });
+
+  it('adds a custom ACP entry (extends:acp + label + command)', () => {
+    const config: CoderProvidersFile = {
+      providers: {
+        'amp-acp': { extends: 'acp', label: 'Amp', description: 'ACP wrapper', command: ['amp-acp', '--acp'], env: { AMP: '1' } },
+      },
+    };
+    const reg = buildResolvedRegistry(PROVIDERS, config);
+    const amp = reg.get('amp-acp');
+    expect(amp).toBeDefined();
+    expect(amp!.isCustomAcp).toBe(true);
+    expect(amp!.isBuiltin).toBe(false);
+    expect(amp!.transport).toBe('acp');
+    expect(amp!.modelSource).toBe('probe');
+    expect(amp!.launchCommand).toEqual(['amp-acp', '--acp']);
+    expect(amp!.env).toEqual({ AMP: '1' });
+    expect(amp!.enabled).toBe(true);
+  });
+
+  it('keeps a disabled built-in in the registry flagged disabled (goose)', () => {
+    const config: CoderProvidersFile = { providers: { goose: { enabled: false } } };
+    const reg = buildResolvedRegistry(PROVIDERS, config);
+    expect(reg.has('goose')).toBe(true);
+    expect(reg.get('goose')!.enabled).toBe(false);
+  });
+
+  it('skips a custom id without extends (no throw)', () => {
+    const config: CoderProvidersFile = { providers: { weird: { label: 'Weird', command: ['weird'] } } };
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    const reg = buildResolvedRegistry(PROVIDERS, config);
+    expect(reg.has('weird')).toBe(false);
+    // built-ins untouched
+    expect(reg.size).toBe(PROVIDERS.length);
+    expect(warn).toHaveBeenCalled();
+    warn.mockRestore();
+  });
+
+  it('ignores enabled:false on boocode and warns', () => {
+    const config: CoderProvidersFile = { providers: { boocode: { enabled: false } } };
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    const reg = buildResolvedRegistry(PROVIDERS, config);
+    expect(reg.get('boocode')!.enabled).toBe(true);
+    expect(warn).toHaveBeenCalled();
+    warn.mockRestore();
+  });
+
+  it('carries config models + additionalModels onto built-in and custom defs', () => {
+    const reg = buildResolvedRegistry(PROVIDERS, {
+      providers: {
+        claude: { models: [{ id: 'claude-opus-4-8', label: 'Opus 4.8' }] },
+        'amp-acp': {
+          extends: 'acp',
+          label: 'Amp',
+          command: ['amp-acp'],
+          additionalModels: [{ id: 'amp-1', label: 'Amp 1' }],
+        },
+      },
+    });
+    expect(reg.get('claude')!.configModels).toEqual([{ id: 'claude-opus-4-8', label: 'Opus 4.8' }]);
+    expect(reg.get('amp-acp')!.configAdditionalModels).toEqual([{ id: 'amp-1', label: 'Amp 1' }]);
+  });
+
+  it('REGRESSION: empty config returns exactly the built-ins, all enabled', () => {
+    const reg = buildResolvedRegistry(PROVIDERS, { providers: {} });
+    expect(reg.size).toBe(PROVIDERS.length);
+    expect([...reg.keys()]).toEqual(PROVIDERS.map((p) => p.name));
+    for (const def of PROVIDERS) {
+      const r = reg.get(def.name)!;
+      expect(r.enabled).toBe(true);
+      expect(r.isBuiltin).toBe(true);
+      expect(r.isCustomAcp).toBe(false);
+      expect(r.launchCommand).toBeNull();
+      expect(r.label).toBe(def.label);
+    }
+  });
+});

apps/coder/src/services/__tests__/provider-config.test.ts

@@ -0,0 +1,96 @@
+import { describe, it, expect } from 'vitest';
+import {
+  mergeProviderConfigPatch,
+  ProviderConfigPatchSchema,
+  CoderProvidersFileSchema,
+  type CoderProvidersFile,
+} from '../provider-config.js';
+
+describe('ProviderConfigPatchSchema', () => {
+  it('accepts a per-provider override patch', () => {
+    const parsed = ProviderConfigPatchSchema.safeParse({ providers: { goose: { enabled: false } } });
+    expect(parsed.success).toBe(true);
+  });
+
+  it('accepts a null value (delete-the-override sentinel)', () => {
+    const parsed = ProviderConfigPatchSchema.safeParse({ providers: { goose: null } });
+    expect(parsed.success).toBe(true);
+  });
+
+  it('defaults providers to {} on an empty body', () => {
+    const parsed = ProviderConfigPatchSchema.safeParse({});
+    expect(parsed.success).toBe(true);
+    if (parsed.success) expect(parsed.data.providers).toEqual({});
+  });
+
+  it('rejects a malformed override (wrong field type)', () => {
+    const parsed = ProviderConfigPatchSchema.safeParse({ providers: { goose: { enabled: 'yes' } } });
+    expect(parsed.success).toBe(false);
+  });
+
+  it('rejects a non-object providers map', () => {
+    const parsed = ProviderConfigPatchSchema.safeParse({ providers: 123 });
+    expect(parsed.success).toBe(false);
+  });
+});
+
+describe('mergeProviderConfigPatch', () => {
+  const current: CoderProvidersFile = {
+    providers: {
+      goose: { enabled: true, label: 'Goose' },
+      opencode: { enabled: true },
+    },
+  };
+
+  it('replaces an existing override object wholesale (not deep-merge)', () => {
+    const merged = mergeProviderConfigPatch(current, { providers: { goose: { enabled: false } } });
+    // Whole override replaced — the prior `label` is gone, only `enabled` remains.
+    expect(merged.providers.goose).toEqual({ enabled: false });
+  });
+
+  it('adds a brand-new override id', () => {
+    const merged = mergeProviderConfigPatch(current, {
+      providers: { 'amp-acp': { extends: 'acp', label: 'Amp', command: ['amp-acp'] } },
+    });
+    expect(merged.providers['amp-acp']).toEqual({ extends: 'acp', label: 'Amp', command: ['amp-acp'] });
+  });
+
+  it('deletes an override when the value is null', () => {
+    const merged = mergeProviderConfigPatch(current, { providers: { goose: null } });
+    expect(merged.providers.goose).toBeUndefined();
+    expect(Object.keys(merged.providers)).toEqual(['opencode']);
+  });
+
+  it('leaves ids absent from the patch untouched', () => {
+    const merged = mergeProviderConfigPatch(current, { providers: { goose: { enabled: false } } });
+    expect(merged.providers.opencode).toEqual({ enabled: true });
+  });
+
+  it('does not mutate the input config', () => {
+    const snapshot = JSON.parse(JSON.stringify(current));
+    mergeProviderConfigPatch(current, { providers: { goose: null, opencode: { enabled: false } } });
+    expect(current).toEqual(snapshot);
+  });
+
+  it('empty patch returns an equivalent config', () => {
+    const merged = mergeProviderConfigPatch(current, { providers: {} });
+    expect(merged).toEqual(current);
+  });
+});
+
+describe('CoderProvidersFileSchema (validate-before-save guard)', () => {
+  it('accepts a clean merged config', () => {
+    const merged = mergeProviderConfigPatch(
+      { providers: {} },
+      { providers: { goose: { enabled: false } } },
+    );
+    expect(CoderProvidersFileSchema.safeParse(merged).success).toBe(true);
+  });
+
+  it('rejects a config carrying an invalid override (never written)', () => {
+    // A merged object that somehow holds a bad override must fail validation
+    // so the PATCH route returns 422 and never calls save().
+    const invalid = { providers: { goose: { enabled: 'nope' } } };
+    expect(CoderProvidersFileSchema.safeParse(invalid).success).toBe(false);
+  });
+});

apps/coder/src/services/__tests__/provider-diagnostic.test.ts

@@ -0,0 +1,85 @@
+import { describe, it, expect } from 'vitest';
+import { getProviderDiagnostic, type DiagnosticAgentRow } from '../provider-diagnostic.js';
+import { buildResolvedRegistry } from '../provider-config-registry.js';
+import { PROVIDERS } from '../provider-registry.js';
+import type { ProviderSnapshotEntry } from '../provider-types.js';
+
+const registry = buildResolvedRegistry(PROVIDERS, {
+  providers: {
+    goose: { enabled: false },
+    'amp-acp': { extends: 'acp', label: 'Amp', command: ['amp-acp', '--acp'] },
+  },
+});
+
+const alwaysAvailable = () => Promise.resolve(true);
+const neverAvailable = () => Promise.resolve(false);
+
+describe('getProviderDiagnostic', () => {
+  it('reports a disabled built-in (enabled:false, no install)', async () => {
+    const report = await getProviderDiagnostic(registry.get('goose')!, undefined, {
+      checkAvailable: neverAvailable,
+    });
+    expect(report).toContain('provider: goose');
+    expect(report).toContain('enabled: false');
+    expect(report).toContain('installed: false');
+    expect(report).toMatch(/command_available:\s*false/);
+  });
+
+  it('reports an installed built-in with its install_path, last_probed_at, model count', async () => {
+    const agentRow: DiagnosticAgentRow = {
+      name: 'opencode',
+      install_path: '/usr/bin/opencode',
+      supports_acp: true,
+      models: [
+        { id: 'm1', label: 'M1' },
+        { id: 'm2', label: 'M2' },
+      ],
+      last_probed_at: '2026-05-29T12:00:00.000Z',
+    };
+    const report = await getProviderDiagnostic(registry.get('opencode')!, agentRow, {
+      checkAvailable: alwaysAvailable,
+    });
+    expect(report).toContain('install_path: /usr/bin/opencode');
+    expect(report).toContain('2026-05-29T12:00:00.000Z');
+    expect(report).toContain('installed: true');
+    expect(report).toMatch(/models_in_db:\s*2/);
+    expect(report).toMatch(/command_available:\s*true/);
+  });
+
+  it('reports a custom ACP launch command + its binary', async () => {
+    const report = await getProviderDiagnostic(registry.get('amp-acp')!, undefined, {
+      checkAvailable: alwaysAvailable,
+    });
+    expect(report).toContain('provider: amp-acp');
+    expect(report).toContain('amp-acp --acp');
+    expect(report).toContain('customAcp: true');
+  });
+
+  it('surfaces the last probe error from a cached snapshot entry', async () => {
+    const cachedEntry: ProviderSnapshotEntry = {
+      name: 'opencode',
+      label: 'OpenCode',
+      transport: 'acp',
+      status: 'error',
+      enabled: true,
+      installed: true,
+      models: [],
+      modes: [],
+      defaultModeId: null,
+      commands: [],
+      error: 'ACP initialize timed out',
+    };
+    const report = await getProviderDiagnostic(registry.get('opencode')!, undefined, {
+      cachedEntry,
+      checkAvailable: alwaysAvailable,
+    });
+    expect(report).toContain('ACP initialize timed out');
+  });
+
+  it('reports no error when none is cached', async () => {
+    const report = await getProviderDiagnostic(registry.get('opencode')!, undefined, {
+      checkAvailable: alwaysAvailable,
+    });
+    expect(report).toMatch(/last_probe_error:\s*\(none/);
+  });
+});

apps/coder/src/services/__tests__/provider-snapshot.test.ts

@@ -1,10 +1,15 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
 import {
   mergeModels,
   prefixLlamaSwapModels,
   clearProviderSnapshotCache,
   getProviderSnapshot,
+  peekSnapshotEntry,
 } from '../provider-snapshot.js';
+import { loadProviderConfig } from '../provider-config-registry.js';
 
 vi.mock('../acp-probe.js', () => ({
   probeAcpProvider: vi.fn(),
@@ -14,6 +19,13 @@ import { probeAcpProvider } from '../acp-probe.js';
 
 const mockProbe = vi.mocked(probeAcpProvider);
 
+/** Write a temp coder-providers.json and point the resolved registry at it. */
+function loadConfigFixture(providers: Record<string, unknown>): void {
+  const path = join(tmpdir(), `coder-providers-test-${providers ? Object.keys(providers).join('-') || 'empty' : 'empty'}.json`);
+  writeFileSync(path, JSON.stringify({ providers }), 'utf8');
+  loadProviderConfig(path);
+}
+
 function mockSql(agents: Array<{
   name: string;
   install_path: string | null;
@@ -21,6 +33,7 @@ function mockSql(agents: Array<{
   models: Array<{ id: string; label: string }> | null;
   label: string | null;
   transport: string | null;
+  last_probed_at?: string | null;
 }>) {
   return vi.fn((strings: TemplateStringsArray) => {
     const query = strings.join('');
@@ -36,6 +49,7 @@ function mockSql(agents: Array<{
 
 const config = {
   LLAMA_SWAP_URL: 'http://llama-swap.test',
+  PROVIDER_PROBE_TTL_MS: 86_400_000,
 } as import('../config.js').Config;
 
 describe('prefixLlamaSwapModels', () => {
@@ -68,6 +82,8 @@ describe('mergeModels', () => {
 describe('getProviderSnapshot', () => {
   beforeEach(() => {
     clearProviderSnapshotCache();
+    // Reset the resolved registry to built-ins-only (missing path → {} config).
+    loadProviderConfig('/nonexistent-coder-providers.json');
     vi.restoreAllMocks();
     vi.stubGlobal(
       'fetch',
@@ -165,4 +181,190 @@ describe('getProviderSnapshot', () => {
     expect(claude?.modes.length).toBeGreaterThan(0);
     expect(claude?.commands.some((c) => c.name === 'help')).toBe(true);
   });
+
+  it('disabled provider → unavailable + enabled:false, WITHOUT spawning a probe', async () => {
+    loadConfigFixture({ goose: { enabled: false } });
+    mockProbe.mockResolvedValue({ ok: true, models: [], modes: [], defaultModeId: null, commands: [] });
+
+    const sql = mockSql([
+      {
+        name: 'goose',
+        install_path: '/usr/bin/goose',
+        supports_acp: true,
+        models: [{ id: 'g1', label: 'G1' }],
+        label: 'Goose',
+        transport: 'acp',
+        last_probed_at: new Date().toISOString(),
+      },
+    ]);
+
+    const entries = await getProviderSnapshot(sql, config, '/tmp/project', true);
+    const goose = entries.find((e) => e.name === 'goose');
+
+    expect(goose?.status).toBe('unavailable');
+    expect(goose?.enabled).toBe(false);
+    expect(goose?.installed).toBe(false);
+    expect(mockProbe).not.toHaveBeenCalled();
+  });
+
+  it('uninstalled provider → unavailable + enabled:true + installed:false', async () => {
+    loadConfigFixture({});
+    mockProbe.mockResolvedValue({ ok: true, models: [], modes: [], defaultModeId: null, commands: [] });
+
+    const sql = mockSql([]); // nothing probed/installed
+    const entries = await getProviderSnapshot(sql, config, '/tmp/project', true);
+    const opencode = entries.find((e) => e.name === 'opencode');
+
+    expect(opencode?.status).toBe('unavailable');
+    expect(opencode?.enabled).toBe(true);
+    expect(opencode?.installed).toBe(false);
+    expect(mockProbe).not.toHaveBeenCalled();
+  });
+
+  it('fresh DB within TTL → tier-2 cold probe SKIPPED (serves DB models)', async () => {
+    loadConfigFixture({});
+    // If this were wrongly called, cached-goose would be replaced and the
+    // not.toHaveBeenCalled assertion would fail.
+    mockProbe.mockResolvedValue({
+      ok: true,
+      models: [{ id: 'SHOULD-NOT-APPEAR', label: 'nope' }],
+      modes: [],
+      defaultModeId: null,
+      commands: [],
+    });
+
+    const sql = mockSql([
+      {
+        name: 'goose',
+        install_path: '/usr/bin/goose',
+        supports_acp: true,
+        models: [{ id: 'cached-goose', label: 'Cached Goose' }],
+        label: 'Goose',
+        transport: 'acp',
+        last_probed_at: new Date().toISOString(), // fresh
+      },
+    ]);
+
+    // force=false → cache-miss returns loading; second call joins the build / cache.
+    await getProviderSnapshot(sql, config, '/tmp/cwd', false);
+    const entries = await getProviderSnapshot(sql, config, '/tmp/cwd', false);
+    const goose = entries.find((e) => e.name === 'goose');
+
+    expect(goose?.status).toBe('ready');
+    expect(goose?.installed).toBe(true);
+    expect(goose?.models.map((m) => m.id)).toContain('cached-goose');
+    expect(goose?.models.map((m) => m.id)).not.toContain('SHOULD-NOT-APPEAR');
+    expect(mockProbe).not.toHaveBeenCalled();
+  });
+
+  it('force refresh → tier-2 cold probe RUNS even when DB is fresh', async () => {
+    loadConfigFixture({});
+    mockProbe.mockResolvedValue({
+      ok: true,
+      models: [{ id: 'fresh-probe', label: 'Fresh' }],
+      modes: [],
+      defaultModeId: null,
+      commands: [],
+    });
+
+    const sql = mockSql([
+      {
+        name: 'goose',
+        install_path: '/usr/bin/goose',
+        supports_acp: true,
+        models: [{ id: 'cached-goose', label: 'Cached' }],
+        label: 'Goose',
+        transport: 'acp',
+        last_probed_at: new Date().toISOString(), // fresh, but force overrides
+      },
+    ]);
+
+    await getProviderSnapshot(sql, config, '/tmp/cwd', true);
+    expect(mockProbe).toHaveBeenCalled();
+  });
+
+  it('native boocode → ready, enabled, installed', async () => {
+    loadConfigFixture({});
+    const sql = mockSql([]);
+    const entries = await getProviderSnapshot(sql, config, '/tmp/project', true);
+    const boocode = entries.find((e) => e.name === 'boocode');
+
+    expect(boocode?.status).toBe('ready');
+    expect(boocode?.enabled).toBe(true);
+    expect(boocode?.installed).toBe(true);
+  });
+
+  it('config models REPLACE the claude static list; additionalModels merge (+ thinking)', async () => {
+    loadConfigFixture({
+      claude: {
+        models: [{ id: 'claude-opus-4-8', label: 'Opus 4.8' }],
+        additionalModels: [{ id: 'sonnet', label: 'Sonnet (latest)' }],
+      },
+    });
+
+    const sql = mockSql([
+      {
+        name: 'claude',
+        install_path: '/usr/bin/claude',
+        supports_acp: false,
+        models: [{ id: 'old-static', label: 'Old' }],
+        label: 'Claude Code',
+        transport: 'pty',
+        last_probed_at: new Date().toISOString(),
+      },
+    ]);
+
+    const entries = await getProviderSnapshot(sql, config, '/tmp/project', true);
+    const claude = entries.find((e) => e.name === 'claude');
+    const ids = claude!.models.map((m) => m.id);
+
+    expect(ids).toContain('claude-opus-4-8'); // config models replaced the DB/static list
+    expect(ids).toContain('sonnet'); // additionalModels merged on top
+    expect(ids).not.toContain('old-static'); // replaced, not appended
+    // thinking options still attach to the config-provided models
+    expect(claude!.models.find((m) => m.id === 'claude-opus-4-8')?.thinkingOptions?.length).toBeGreaterThan(0);
+  });
+
+  it('peekSnapshotEntry returns a cached entry (read-only) and undefined when cold/unknown', async () => {
+    loadConfigFixture({});
+    // Cold cache → undefined (no build triggered).
+    expect(peekSnapshotEntry('boocode', '/tmp/peek')).toBeUndefined();
+
+    const sql = mockSql([]);
+    await getProviderSnapshot(sql, config, '/tmp/peek', true);
+
+    expect(peekSnapshotEntry('boocode', '/tmp/peek')?.name).toBe('boocode');
+    expect(peekSnapshotEntry('does-not-exist', '/tmp/peek')).toBeUndefined();
+  });
+
+  it('2.7 warm cache: a second snapshot within the warm window spawns ZERO probes', async () => {
+    loadConfigFixture({});
+    mockProbe.mockResolvedValue({
+      ok: true,
+      models: [{ id: 'm1', label: 'M1' }],
+      modes: [],
+      defaultModeId: null,
+      commands: [],
+    });
+
+    const sql = mockSql([
+      {
+        name: 'goose',
+        install_path: '/usr/bin/goose',
+        supports_acp: true,
+        models: null,
+        label: 'Goose',
+        transport: 'acp',
+        last_probed_at: null,
+      },
+    ]);
+
+    await getProviderSnapshot(sql, config, '/tmp/cwd', true); // cold populate
+    const probeCallsAfterFirst = mockProbe.mock.calls.length;
+    await getProviderSnapshot(sql, config, '/tmp/cwd', false); // warm read
+    const probeCallsAfterSecond = mockProbe.mock.calls.length;
+
+    // Success criterion: second snapshot is served from cache with no ACP spawns.
+    expect(probeCallsAfterSecond - probeCallsAfterFirst).toBe(0);
+  });
 });

apps/coder/src/services/__tests__/reconnect_integration.test.ts

@@ -0,0 +1,170 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { readFileSync, existsSync } from 'node:fs';
+import { rm, mkdir } from 'node:fs/promises';
+import { resolve } from 'node:path';
+import postgres from 'postgres';
+import {
+  ensureSessionWorktree,
+  closeChatBackendState,
+  rebaselineWorktreeAfterApply,
+} from '../worktrees.js';
+import { reapOrphanWorktrees } from '../orphan-worktree-reaper.js';
+import { hostExec } from '../host-exec.js';
+
+/**
+ * v2.6 Phase 3 (3.6) — reconnect-after-restart integration test.
+ *
+ * Proves the DB-truth side of crash/restart recovery: a BooCoder restart wipes the
+ * in-memory pool, but the persistent `worktrees` + `agent_sessions` rows survive,
+ * so the "next turn" re-resolves the SAME worktree (reattach, no new dir) and the
+ * agent-session row is still there to resume from. Also exercises the chat-close
+ * hook (3.3), the apply re-baseline (3.5), and the orphan reaper (3.4) end-to-end
+ * against a real git repo + postgres.
+ *
+ * Requires DATABASE_URL (DB-opt-in; skips cleanly otherwise) AND git on PATH. Runs:
+ *   DATABASE_URL='postgres://boocode:devpass@localhost:5500/boochat' pnpm -C apps/coder test
+ */
+describe.runIf(!!process.env.DATABASE_URL)('reconnect after restart (Phase 3)', () => {
+  let sql: ReturnType<typeof postgres>;
+  const stamp = Date.now();
+  const projectDir = `/tmp/boocode-reconnect-proj-${stamp}`;
+  let projectId: string;
+  let sessionId: string;
+  let chatId: string;
+
+  beforeAll(async () => {
+    sql = postgres(process.env.DATABASE_URL!, { max: 3 });
+
+    // Both schemas land in the one boochat DB: server owns sessions/chats/projects,
+    // coder owns worktrees/agent_sessions (FK targets must pre-exist → server first).
+    const serverSchema = resolve(__dirname, '../../../../server/src/schema.sql');
+    const coderSchema = resolve(__dirname, '../../schema.sql');
+    await sql.unsafe(readFileSync(serverSchema, 'utf8'));
+    await sql.unsafe(readFileSync(coderSchema, 'utf8'));
+
+    // A real git repo with one commit so worktree add / diff / rev-parse work.
+    await mkdir(projectDir, { recursive: true });
+    await hostExec(
+      `cd ${projectDir} && git init -q && git config user.email t@t && git config user.name t ` +
+        `&& echo hello > README.md && git add -A && git commit -qm init`,
+      { timeoutMs: 20_000 },
+    );
+
+    const [project] = await sql<{ id: string }[]>`
+      INSERT INTO projects (name, path, status) VALUES ('reconnect-test', ${projectDir}, 'open') RETURNING id
+    `;
+    projectId = project!.id;
+    const [session] = await sql<{ id: string }[]>`
+      INSERT INTO sessions (project_id, name, model, status)
+      VALUES (${projectId}, 'recon', 'm', 'open') RETURNING id
+    `;
+    sessionId = session!.id;
+    const [chat] = await sql<{ id: string }[]>`
+      INSERT INTO chats (session_id, name, status) VALUES (${sessionId}, 'tab', 'open') RETURNING id
+    `;
+    chatId = chat!.id;
+  });
+
+  afterAll(async () => {
+    if (sql) {
+      // Best-effort worktree cleanup before dropping rows.
+      const rows = await sql<{ path: string }[]>`SELECT path FROM worktrees WHERE session_id = ${sessionId}`.catch(() => []);
+      for (const r of rows) {
+        await hostExec(`git -C ${projectDir} worktree remove ${r.path} --force`, { timeoutMs: 10_000 }).catch(() => {});
+      }
+      await sql`DELETE FROM agent_sessions WHERE chat_id = ${chatId}`.catch(() => {});
+      await sql`DELETE FROM worktrees WHERE session_id = ${sessionId}`.catch(() => {});
+      await sql`DELETE FROM chats WHERE id = ${chatId}`.catch(() => {});
+      await sql`DELETE FROM sessions WHERE id = ${sessionId}`.catch(() => {});
+      await sql`DELETE FROM projects WHERE id = ${projectId}`.catch(() => {});
+      await sql.end({ timeout: 5 });
+    }
+    await rm(projectDir, { recursive: true, force: true });
+  });
+
+  it('reattaches the SAME worktree across a simulated restart (no new dir)', async () => {
+    // "Turn 1" — first ensureSessionWorktree creates the worktree + row.
+    const first = await ensureSessionWorktree(sql, projectDir, sessionId);
+    expect(existsSync(first.worktreePath)).toBe(true);
+    expect(first.baseCommit).toBeTruthy();
+
+    // Simulate an agent_sessions row written by turn 1 (opencode).
+    await sql`
+      INSERT INTO agent_sessions (chat_id, session_id, worktree_id, agent, backend, agent_session_id, status, last_active_at)
+      VALUES (${chatId}, ${sessionId}, ${first.worktreeId}, 'opencode', 'opencode_server', 'oc-sess-1', 'active', clock_timestamp())
+      ON CONFLICT (chat_id, agent) DO NOTHING
+    `;
+
+    // "Restart" = brand-new resolution with NO in-memory state. ensureSessionWorktree
+    // must return the EXISTING row (same id + path), proving reattach not re-create.
+    const second = await ensureSessionWorktree(sql, projectDir, sessionId);
+    expect(second.worktreeId).toBe(first.worktreeId);
+    expect(second.worktreePath).toBe(first.worktreePath);
+    expect(second.baseCommit).toBe(first.baseCommit);
+
+    // The agent_sessions row survived the "restart" with its resume handle intact.
+    const [row] = await sql<{ agent_session_id: string; status: string }[]>`
+      SELECT agent_session_id, status FROM agent_sessions WHERE chat_id = ${chatId} AND agent = 'opencode'
+    `;
+    expect(row!.agent_session_id).toBe('oc-sess-1');
+  });
+
+  it('re-baselines the worktree diff after apply (3.5)', async () => {
+    const wt = await ensureSessionWorktree(sql, projectDir, sessionId);
+    const baseBefore = wt.baseCommit;
+    // Make a change in the worktree (as an external agent would).
+    await hostExec(`cd ${wt.worktreePath} && echo change >> README.md`, { timeoutMs: 10_000 });
+
+    const r = await rebaselineWorktreeAfterApply(sql, sessionId);
+    expect(r.rebaselined).toBe(true);
+    expect(r.newBaseCommit).toBeTruthy();
+    expect(r.newBaseCommit).not.toBe(baseBefore);
+
+    const [row] = await sql<{ base_commit: string }[]>`
+      SELECT base_commit FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'
+    `;
+    expect(row!.base_commit).toBe(r.newBaseCommit);
+
+    // Idempotent: a second re-baseline with no new edits is a no-op.
+    const r2 = await rebaselineWorktreeAfterApply(sql, sessionId);
+    expect(r2.rebaselined).toBe(false);
+  });
+
+  it('chat-close hook closes agent rows + removes the worktree on the last chat (3.3)', async () => {
+    // Sanity: an active worktree + agent row exist from the prior tests.
+    const beforeWt = await sql<{ id: string }[]>`SELECT id FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'`;
+    expect(beforeWt.length).toBe(1);
+
+    const result = await closeChatBackendState(sql, chatId);
+    expect(result.agentRowsClosed).toBeGreaterThanOrEqual(1);
+    // chatId is the session's only chat → worktree removed (it was clean after the
+    // re-baseline commit), not at-risk.
+    expect(result.worktreeAtRisk).toBe(false);
+    expect(result.worktreeRemoved).toBe(true);
+
+    const [agentRow] = await sql<{ status: string }[]>`
+      SELECT status FROM agent_sessions WHERE chat_id = ${chatId} AND agent = 'opencode'
+    `;
+    expect(agentRow!.status).toBe('closed');
+
+    const activeWt = await sql<{ id: string }[]>`SELECT id FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'`;
+    expect(activeWt.length).toBe(0); // archived, no longer active
+  });
+
+  it('orphan reaper leaves a live worktree alone and reaps a row-less dir (3.4)', async () => {
+    // Recreate a live worktree for this session (the close test archived the old one).
+    const live = await ensureSessionWorktree(sql, projectDir, sessionId);
+    expect(existsSync(live.worktreePath)).toBe(true);
+
+    // A live worktree (active row) with grace 0 must NOT be reaped.
+    const r1 = await reapOrphanWorktrees(sql, console as never, 0, Date.now());
+    expect(r1.reaped).not.toContain(live.worktreePath);
+
+    // Now archive its row (simulating a leaked dir) and reap again — it becomes an
+    // orphan and is reclaimed (it's clean → not at-risk).
+    await sql`UPDATE worktrees SET status = 'archived' WHERE id = ${live.worktreeId}`;
+    const r2 = await reapOrphanWorktrees(sql, console as never, 0, Date.now());
+    expect(r2.reaped).toContain(live.worktreePath);
+    expect(existsSync(live.worktreePath)).toBe(false);
+  });
+});

apps/coder/src/services/__tests__/stream-json-parser.test.ts

@@ -0,0 +1,189 @@
+import { describe, it, expect } from 'vitest';
+import {
+  makeStreamJsonParser,
+  makeStreamJsonState,
+  parseStreamJsonLine,
+  type AgentEventList,
+} from '../stream-json-parser.js';
+import type { AgentEvent } from '../agent-backend.js';
+import type { AcpToolSnapshot } from '../acp-tool-snapshot.js';
+
+// Helpers to JSON-encode the representative Claude-Code stream-json lines.
+const sys = (sessionId: string) =>
+  JSON.stringify({ type: 'system', subtype: 'init', session_id: sessionId, tools: ['read', 'edit'] });
+
+const streamEvent = (event: unknown) => JSON.stringify({ type: 'stream_event', event });
+
+const textDelta = (index: number, text: string) =>
+  streamEvent({ type: 'content_block_delta', index, delta: { type: 'text_delta', text } });
+
+const thinkingDelta = (index: number, thinking: string) =>
+  streamEvent({ type: 'content_block_delta', index, delta: { type: 'thinking_delta', thinking } });
+
+const toolStart = (index: number, id: string, name: string) =>
+  streamEvent({ type: 'content_block_start', index, content_block: { type: 'tool_use', id, name } });
+
+const inputJsonDelta = (index: number, partial: string) =>
+  streamEvent({ type: 'content_block_delta', index, delta: { type: 'input_json_delta', partial_json: partial } });
+
+const blockStop = (index: number) => streamEvent({ type: 'content_block_stop', index });
+
+const resultLine = (input: number, output: number, sessionId?: string) =>
+  JSON.stringify({ type: 'result', subtype: 'success', session_id: sessionId, usage: { input_tokens: input, output_tokens: output } });
+
+describe('parseStreamJsonLine (pure per-line mapping)', () => {
+  it('captures session_id from the system init line and emits no events', () => {
+    const state = makeStreamJsonState();
+    const events = parseStreamJsonLine(sys('sess-abc'), state);
+    expect(events).toEqual([]);
+    expect(state.sessionId).toBe('sess-abc');
+  });
+
+  it('maps a text_delta stream_event → a text event', () => {
+    const state = makeStreamJsonState();
+    expect(parseStreamJsonLine(textDelta(0, 'Hello'), state)).toEqual([{ type: 'text', text: 'Hello' }]);
+  });
+
+  it('maps a thinking_delta stream_event → a reasoning event', () => {
+    const state = makeStreamJsonState();
+    expect(parseStreamJsonLine(thinkingDelta(0, 'pondering'), state)).toEqual([
+      { type: 'reasoning', text: 'pondering' },
+    ]);
+  });
+
+  it('tolerates a garbage / non-JSON line (returns [], no throw)', () => {
+    const state = makeStreamJsonState();
+    expect(parseStreamJsonLine('not json at all {{{', state)).toEqual([]);
+    expect(parseStreamJsonLine('', state)).toEqual([]);
+    expect(parseStreamJsonLine('   ', state)).toEqual([]);
+    // A truncated/partial JSON object also yields [] rather than throwing.
+    expect(parseStreamJsonLine('{"type":"stream_event","eve', state)).toEqual([]);
+  });
+
+  it('ignores unknown top-level line types and the user (tool-result) line', () => {
+    const state = makeStreamJsonState();
+    expect(parseStreamJsonLine(JSON.stringify({ type: 'user', message: {} }), state)).toEqual([]);
+    expect(parseStreamJsonLine(JSON.stringify({ type: 'whatever' }), state)).toEqual([]);
+  });
+
+  it('assembles a tool call across input_json_delta chunks (split across lines)', () => {
+    const state = makeStreamJsonState();
+    // start → tool_call (running, empty args)
+    const start = parseStreamJsonLine(toolStart(1, 'toolu_1', 'edit_file'), state);
+    expect(start).toHaveLength(1);
+    expect(start[0]!.type).toBe('tool_call');
+    const startSnap = (start[0] as { type: 'tool_call'; toolCall: AcpToolSnapshot }).toolCall;
+    expect(startSnap.toolCallId).toBe('toolu_1');
+    expect(startSnap.title).toBe('edit_file');
+    expect(startSnap.status).toBe('in_progress');
+    expect(startSnap.rawInput).toEqual({});
+
+    // args streamed in fragments — no events until stop
+    expect(parseStreamJsonLine(inputJsonDelta(1, '{"path":"a'), state)).toEqual([]);
+    expect(parseStreamJsonLine(inputJsonDelta(1, '.ts","content":'), state)).toEqual([]);
+    expect(parseStreamJsonLine(inputJsonDelta(1, '"hi"}'), state)).toEqual([]);
+
+    // stop → tool_update with the parsed, fully-assembled input
+    const stop = parseStreamJsonLine(blockStop(1), state);
+    expect(stop).toHaveLength(1);
+    expect(stop[0]!.type).toBe('tool_update');
+    const stopSnap = (stop[0] as { type: 'tool_update'; toolCall: AcpToolSnapshot }).toolCall;
+    expect(stopSnap.toolCallId).toBe('toolu_1');
+    expect(stopSnap.status).toBe('completed');
+    expect(stopSnap.rawInput).toEqual({ path: 'a.ts', content: 'hi' });
+  });
+
+  it('falls back to {_raw} when accumulated tool args are not valid JSON', () => {
+    const state = makeStreamJsonState();
+    parseStreamJsonLine(toolStart(0, 'toolu_x', 'run'), state);
+    parseStreamJsonLine(inputJsonDelta(0, '{"broken'), state);
+    const stop = parseStreamJsonLine(blockStop(0), state);
+    const snap = (stop[0] as { type: 'tool_update'; toolCall: AcpToolSnapshot }).toolCall;
+    expect(snap.rawInput).toEqual({ _raw: '{"broken' });
+  });
+
+  it('captures usage from message_delta and result lines', () => {
+    const state = makeStreamJsonState();
+    parseStreamJsonLine(streamEvent({ type: 'message_delta', usage: { output_tokens: 42 } }), state);
+    expect(state.usage.outputTokens).toBe(42);
+    parseStreamJsonLine(resultLine(100, 250, 'sess-z'), state);
+    expect(state.usage.inputTokens).toBe(100);
+    expect(state.usage.outputTokens).toBe(250);
+    expect(state.sessionId).toBe('sess-z');
+  });
+
+  it('maps a terminal assistant message (fallback) → text + reasoning + tool events', () => {
+    const state = makeStreamJsonState();
+    const line = JSON.stringify({
+      type: 'assistant',
+      session_id: 'sess-asst',
+      message: {
+        content: [
+          { type: 'thinking', thinking: 'let me think' },
+          { type: 'text', text: 'Here is the answer' },
+          { type: 'tool_use', id: 'toolu_9', name: 'view_file', input: { path: 'x.ts' } },
+        ],
+        usage: { input_tokens: 5, output_tokens: 7 },
+      },
+    });
+    const events = parseStreamJsonLine(line, state);
+    expect(events).toEqual([
+      { type: 'reasoning', text: 'let me think' },
+      { type: 'text', text: 'Here is the answer' },
+      {
+        type: 'tool_update',
+        toolCall: { toolCallId: 'toolu_9', title: 'view_file', kind: null, status: 'completed', rawInput: { path: 'x.ts' } },
+      },
+    ]);
+    expect(state.usage).toEqual({ inputTokens: 5, outputTokens: 7 });
+    expect(state.sessionId).toBe('sess-asst');
+  });
+});
+
+describe('makeStreamJsonParser (stateful wrapper over a full turn)', () => {
+  it('streams a representative turn: init → text → thinking → tool → result', () => {
+    const parser = makeStreamJsonParser();
+    const all: AgentEvent[] = [];
+    const feed = (line: string): AgentEventList => {
+      const evs = parser.push(line);
+      all.push(...evs);
+      return evs;
+    };
+
+    feed(sys('sess-1'));
+    feed(textDelta(0, 'Reading '));
+    feed(textDelta(0, 'the file. '));
+    feed(thinkingDelta(0, 'I should edit it'));
+    feed(toolStart(1, 'toolu_a', 'edit_file'));
+    feed(inputJsonDelta(1, '{"path":'));
+    feed(inputJsonDelta(1, '"main.ts"}'));
+    feed(blockStop(1));
+    feed(textDelta(0, 'Done.'));
+    feed(resultLine(120, 80, 'sess-1'));
+
+    expect(all).toEqual([
+      { type: 'text', text: 'Reading ' },
+      { type: 'text', text: 'the file. ' },
+      { type: 'reasoning', text: 'I should edit it' },
+      {
+        type: 'tool_call',
+        toolCall: { toolCallId: 'toolu_a', title: 'edit_file', kind: null, status: 'in_progress', rawInput: {} },
+      },
+      {
+        type: 'tool_update',
+        toolCall: { toolCallId: 'toolu_a', title: 'edit_file', kind: null, status: 'completed', rawInput: { path: 'main.ts' } },
+      },
+      { type: 'text', text: 'Done.' },
+    ]);
+
+    expect(parser.usage()).toEqual({ inputTokens: 120, outputTokens: 80 });
+    expect(parser.sessionId()).toBe('sess-1');
+  });
+
+  it('a garbage line interleaved mid-turn does not derail subsequent parsing', () => {
+    const parser = makeStreamJsonParser();
+    expect(parser.push(textDelta(0, 'a'))).toEqual([{ type: 'text', text: 'a' }]);
+    expect(parser.push('>>> not json <<<')).toEqual([]);
+    expect(parser.push(textDelta(0, 'b'))).toEqual([{ type: 'text', text: 'b' }]);
+  });
+});

apps/coder/src/services/acp-client-fs.ts

@@ -1,5 +1,25 @@
 import { promises as fs } from 'node:fs';
-import { dirname, isAbsolute, join, resolve } from 'node:path';
+import { dirname, isAbsolute, resolve, sep } from 'node:path';
+
+/**
+ * Resolve an ACP-supplied path against the agent worktree and reject anything
+ * that escapes it. Mirrors `write_guard.ts`'s check: `resolve()` to normalize
+ * `../` segments, then a **separator-bounded** prefix test — a bare
+ * `startsWith(root)` wrongly admits a sibling dir like `<root>-evil/...`.
+ *
+ * No realpath (consistent with `write_guard.ts`: the target may not exist yet on
+ * write). This is a containment guard for the ACP fs bridge, not a hard trust
+ * boundary — the agent process already runs with host FS access; symlink-swap
+ * hardening (`O_NOFOLLOW`/realpath) is out of scope here.
+ */
+function resolveInWorktree(worktreePath: string, filePath: string): string {
+  const root = resolve(worktreePath);
+  const absolute = isAbsolute(filePath) ? resolve(filePath) : resolve(root, filePath);
+  if (absolute !== root && !absolute.startsWith(root + sep)) {
+    throw new Error(`path escapes worktree: ${filePath}`);
+  }
+  return absolute;
+}
 
 /** Resolve an ACP path against the agent worktree and read a slice of lines. */
 export async function readWorktreeTextFile(
@@ -8,10 +28,7 @@ export async function readWorktreeTextFile(
   line?: number | null,
   limit?: number | null,
 ): Promise<string> {
-  const absolute = isAbsolute(filePath) ? filePath : resolve(worktreePath, filePath);
-  if (!absolute.startsWith(resolve(worktreePath))) {
-    throw new Error(`path escapes worktree: ${filePath}`);
-  }
+  const absolute = resolveInWorktree(worktreePath, filePath);
   const raw = await fs.readFile(absolute, 'utf8');
   if (!line && !limit) return raw;
   const lines = raw.split(/\r?\n/);
@@ -26,10 +43,7 @@ export async function writeWorktreeTextFile(
   filePath: string,
   content: string,
 ): Promise<void> {
-  const absolute = isAbsolute(filePath) ? filePath : resolve(worktreePath, filePath);
-  if (!absolute.startsWith(resolve(worktreePath))) {
-    throw new Error(`path escapes worktree: ${filePath}`);
-  }
+  const absolute = resolveInWorktree(worktreePath, filePath);
   await fs.mkdir(dirname(absolute), { recursive: true });
   await fs.writeFile(absolute, content, 'utf8');
 }

apps/coder/src/services/acp-client.ts

@@ -0,0 +1,88 @@
+/**
+ * Shared ACP `Client` builder — the callback closures every ACP connection needs
+ * (worktree-scoped FS bridge + permission/elicitation routing + session updates).
+ *
+ * Extracted (v2.7 audit reshape) from the byte-identical `buildClient` closures in
+ * `acp-dispatch.ts` (one-shot) and `backends/warm-acp.ts` (warm). The two differed
+ * only in WHERE the per-turn context comes from (a fixed dispatch vs. the warm
+ * backend's `activeTurn`) and a trivially-equivalent permission gate — both are now
+ * supplied via the `resolveTurn` callback, so the FS/permission/elicitation wiring
+ * lives once. Behavior is preserved exactly:
+ *   - `sessionUpdate` drops when `resolveTurn()` returns null (between turns).
+ *   - permission/elicitation route to the UI only when BOTH a taskId AND sessionId
+ *     are present (warm always has a sessionId, so this matches its prior
+ *     `turn?.taskId` gate); otherwise the same auto-select-first / decline fallback.
+ */
+import type {
+  Client,
+  SessionNotification,
+  RequestPermissionRequest,
+  RequestPermissionResponse,
+  ReadTextFileRequest,
+  ReadTextFileResponse,
+  WriteTextFileRequest,
+  WriteTextFileResponse,
+  CreateTerminalRequest,
+  CreateTerminalResponse,
+  CreateElicitationRequest,
+  CreateElicitationResponse,
+} from '@agentclientprotocol/sdk';
+import { readWorktreeTextFile, writeWorktreeTextFile } from './acp-client-fs.js';
+import { waitForPermissionResponse, waitForElicitationResponse } from './permission-waiter.js';
+
+/** The per-turn context an ACP `Client` closure needs, resolved lazily per call. */
+export interface AcpTurnContext {
+  /** Per-turn task id, for routing permission/elicitation prompts back to the UI. */
+  taskId: string | undefined;
+  /** BooCode session id (for permission-waiter's broker frames). */
+  sessionId: string | undefined;
+  /** Per-turn mode id (autonomous-mode gate in permission-waiter). */
+  modeId: string | undefined;
+  /** The agent name (for permission-waiter routing). */
+  agent: string;
+  /** Forward a session/update notification to the turn's event sink. */
+  onSessionUpdate: (params: SessionNotification) => void | Promise<void>;
+}
+
+/**
+ * Build the ACP `Client` callbacks once per connection. `resolveTurn` is called at
+ * the moment each callback fires and returns the live turn context (or null when no
+ * turn is active — `sessionUpdate` then drops, matching the warm backend's
+ * between-turns behavior). The FS bridge is scoped to `worktreePath`.
+ */
+export function buildAcpClient(worktreePath: string, resolveTurn: () => AcpTurnContext | null): Client {
+  return {
+    sessionUpdate: async (params: SessionNotification): Promise<void> => {
+      const turn = resolveTurn();
+      if (!turn) return; // between turns — drop (no orphan settles a future turn)
+      await turn.onSessionUpdate(params);
+    },
+    requestPermission: async (params: RequestPermissionRequest): Promise<RequestPermissionResponse> => {
+      const turn = resolveTurn();
+      if (turn && turn.taskId && turn.sessionId) {
+        return waitForPermissionResponse(turn.taskId, turn.sessionId, turn.agent, turn.modeId, params);
+      }
+      const firstOption = params.options[0];
+      if (firstOption) return { outcome: { outcome: 'selected', optionId: firstOption.optionId } };
+      return { outcome: { outcome: 'cancelled' } };
+    },
+    readTextFile: async (params: ReadTextFileRequest): Promise<ReadTextFileResponse> => {
+      const content = await readWorktreeTextFile(worktreePath, params.path, params.line, params.limit);
+      return { content };
+    },
+    writeTextFile: async (params: WriteTextFileRequest): Promise<WriteTextFileResponse> => {
+      await writeWorktreeTextFile(worktreePath, params.path, params.content);
+      return {};
+    },
+    createTerminal: async (_params: CreateTerminalRequest): Promise<CreateTerminalResponse> => {
+      return { terminalId: 'noop' };
+    },
+    unstable_createElicitation: async (params: CreateElicitationRequest): Promise<CreateElicitationResponse> => {
+      const turn = resolveTurn();
+      if (turn && turn.taskId && turn.sessionId) {
+        return waitForElicitationResponse(turn.taskId, turn.sessionId, turn.agent, turn.modeId, params);
+      }
+      return { action: 'decline' };
+    },
+  };
+}

apps/coder/src/services/acp-dispatch.ts

@@ -9,34 +9,21 @@ import {
   ClientSideConnection,
   type Client,
   type SessionNotification,
-  type RequestPermissionRequest,
-  type RequestPermissionResponse,
-  type ReadTextFileRequest,
-  type ReadTextFileResponse,
-  type WriteTextFileRequest,
-  type WriteTextFileResponse,
-  type CreateTerminalRequest,
-  type CreateTerminalResponse,
-  type CreateElicitationRequest,
-  type CreateElicitationResponse,
   type SessionConfigOption,
   type ClientSideConnection as ConnectionType,
 } from '@agentclientprotocol/sdk';
 import type { Broker } from '@boocode/server/broker';
-import type { WsFrame } from '@boocode/server/ws-frames';
+
 import { spawn } from 'node:child_process';
 import { findThoughtLevelConfigId } from './acp-derive.js';
-import { resolveAcpSpawnArgs } from './acp-spawn.js';
+import { resolveLaunchSpec } from './acp-spawn.js';
+import { getResolvedRegistry, type ResolvedProviderDef } from './provider-config-registry.js';
 import { createAcpNdJsonStream } from './acp-stream.js';
-import { waitForPermissionResponse, waitForElicitationResponse, cancelPendingPermission } from './permission-waiter.js';
-import { mergeTaskCommands, getTaskCommands } from './agent-commands-cache.js';
-import { readWorktreeTextFile, writeWorktreeTextFile } from './acp-client-fs.js';
-import {
-  type AcpToolSnapshot,
-  mergeToolSnapshot,
-  snapshotToWireToolCall,
-  synthesizeCanceledSnapshots,
-} from './acp-tool-snapshot.js';
+import { cancelPendingPermission } from './permission-waiter.js';
+import { mapSessionUpdate } from './acp-event-map.js';
+import { type AcpToolSnapshot, synthesizeCanceledSnapshots } from './acp-tool-snapshot.js';
+import { makeFrameEmitter, type FrameEmitter } from './frame-emitter.js';
+import { buildAcpClient } from './acp-client.js';
 
 export interface AcpDispatchResult {
   exitCode: number;
@@ -59,6 +46,9 @@ export interface AcpDispatchOpts {
   messageId?: string;
   broker?: Broker;
   installPath?: string;
+  /** v2.3 phase 3: resolved registry def for launch-spec resolution. The
+   *  dispatcher loads this by task.agent; falls back to a registry lookup here. */
+  resolved?: ResolvedProviderDef;
   signal?: AbortSignal;
   log: FastifyBaseLogger;
 }
@@ -107,162 +97,61 @@ async function applySessionOverrides(
 }
 
 class AcpStreamContext {
-  readonly textChunks: string[] = [];
-  readonly reasoningChunks: string[] = [];
-  readonly toolSnapshots = new Map<string, AcpToolSnapshot>();
-  private aborted = false;
+  /** AgentEvent → WS-frame mapping + text/reasoning/tool accumulation (shared
+   *  `makeFrameEmitter`). The one-shot path passes no `dcp` stripper, so text is
+   *  emitted verbatim — byte-identical to the prior inline switch. */
+  private readonly emitter: FrameEmitter;
 
   constructor(
-    private readonly opts: Pick<
-      AcpDispatchOpts,
-      'broker' | 'sessionId' | 'chatId' | 'messageId' | 'taskId'
-    >,
+    opts: Pick<AcpDispatchOpts, 'broker' | 'sessionId' | 'chatId' | 'messageId' | 'taskId'>,
     private readonly worktreePath: string,
-  ) {}
+  ) {
+    this.emitter = makeFrameEmitter({
+      broker: opts.broker,
+      sessionId: opts.sessionId,
+      chatId: opts.chatId,
+      assistantId: opts.messageId,
+      taskId: opts.taskId,
+    });
+  }
 
   get reasoningText(): string {
-    return this.reasoningChunks.join('');
+    return this.emitter.reasoningText;
   }
 
   get output(): string {
-    return this.textChunks.join('');
+    return this.emitter.output;
   }
 
   get snapshots(): AcpToolSnapshot[] {
-    return [...this.toolSnapshots.values()];
+    return this.emitter.snapshots;
   }
 
   markAborted(): void {
-    this.aborted = true;
-    for (const snap of synthesizeCanceledSnapshots(this.toolSnapshots.values())) {
-      this.toolSnapshots.set(snap.toolCallId, snap);
-      this.publishToolSnapshot(snap);
+    // Synthesize 'canceled' updates for still-running tool calls so the UI doesn't
+    // leave them spinning, then emit them through the same frame path (tool_update
+    // → the same `tool_call` wire frame the original published).
+    for (const snap of synthesizeCanceledSnapshots(this.emitter.toolSnapshots.values())) {
+      this.emitter.onEvent({ type: 'tool_update', toolCall: snap });
     }
   }
 
-  private canStream(): boolean {
-    return !!(this.opts.broker && this.opts.sessionId && this.opts.chatId && this.opts.messageId);
-  }
-
-  private publishToolSnapshot(snapshot: AcpToolSnapshot): void {
-    if (!this.canStream()) return;
-    const wire = snapshotToWireToolCall(snapshot);
-    this.opts.broker!.publishFrame(this.opts.sessionId!, {
-      type: 'tool_call',
-      message_id: this.opts.messageId!,
-      chat_id: this.opts.chatId!,
-      tool_call: wire,
-    } as WsFrame);
-  }
-
-  handleToolUpdate(toolCallId: string, update: Parameters<typeof mergeToolSnapshot>[1]): void {
-    const previous = this.toolSnapshots.get(toolCallId);
-    const snapshot = mergeToolSnapshot(toolCallId, update, previous);
-    this.toolSnapshots.set(toolCallId, snapshot);
-    this.publishToolSnapshot(snapshot);
-  }
-
-  async handleSessionUpdate(params: SessionNotification): Promise<void> {
-    const update = params.update;
-    switch (update.sessionUpdate) {
-      case 'agent_message_chunk': {
-        const content = update.content;
-        if (content.type === 'text' && 'text' in content) {
-          const text = (content as { text: string }).text;
-          this.textChunks.push(text);
-          if (this.canStream()) {
-            this.opts.broker!.publishFrame(this.opts.sessionId!, {
-              type: 'delta',
-              message_id: this.opts.messageId!,
-              chat_id: this.opts.chatId!,
-              content: text,
-            } as WsFrame);
-          }
-        }
-        break;
-      }
-      case 'agent_thought_chunk': {
-        const content = update.content;
-        if (content.type === 'text' && 'text' in content) {
-          const text = (content as { text: string }).text;
-          this.reasoningChunks.push(text);
-          if (this.canStream()) {
-            this.opts.broker!.publishFrame(this.opts.sessionId!, {
-              type: 'reasoning_delta',
-              message_id: this.opts.messageId!,
-              chat_id: this.opts.chatId!,
-              content: text,
-            } as WsFrame);
-          }
-        }
-        break;
-      }
-      case 'tool_call':
-        this.handleToolUpdate(update.toolCallId, update);
-        break;
-      case 'tool_call_update':
-        this.handleToolUpdate(update.toolCallId, update);
-        break;
-      case 'available_commands_update': {
-        const commands = update.availableCommands.map((cmd) => ({
-          name: cmd.name,
-          description: cmd.description ?? undefined,
-        }));
-        if (this.opts.taskId && commands.length > 0) {
-          mergeTaskCommands(this.opts.taskId, commands);
-          if (this.canStream() && this.opts.sessionId) {
-            const all = getTaskCommands(this.opts.taskId) ?? commands;
-            this.opts.broker!.publishFrame(this.opts.sessionId, {
-              type: 'agent_commands',
-              task_id: this.opts.taskId,
-              session_id: this.opts.sessionId,
-              commands: all,
-            } as WsFrame);
-          }
-        }
-        break;
-      }
-      default:
-        break;
+  handleSessionUpdate(params: SessionNotification): void {
+    // The merge accumulator (`this.emitter.toolSnapshots`) is the same Map the
+    // emitter publishes from, so a later tool_call_update merges over its tool_call.
+    for (const event of mapSessionUpdate(params, this.emitter.toolSnapshots)) {
+      this.emitter.onEvent(event);
     }
   }
 
   buildClient(agent: string, modeId: string | undefined, taskId: string | undefined, sessionId: string | undefined): Client {
-    return {
-      sessionUpdate: (params) => this.handleSessionUpdate(params),
-      requestPermission: async (params: RequestPermissionRequest): Promise<RequestPermissionResponse> => {
-        if (taskId && sessionId) {
-          return waitForPermissionResponse(taskId, sessionId, agent, modeId, params);
-        }
-        const firstOption = params.options[0];
-        if (firstOption) {
-          return { outcome: { outcome: 'selected', optionId: firstOption.optionId } };
-        }
-        return { outcome: { outcome: 'cancelled' } };
-      },
-      readTextFile: async (params: ReadTextFileRequest): Promise<ReadTextFileResponse> => {
-        const content = await readWorktreeTextFile(
-          this.worktreePath,
-          params.path,
-          params.line,
-          params.limit,
-        );
-        return { content };
-      },
-      writeTextFile: async (params: WriteTextFileRequest): Promise<WriteTextFileResponse> => {
-        await writeWorktreeTextFile(this.worktreePath, params.path, params.content);
-        return {};
-      },
-      createTerminal: async (_params: CreateTerminalRequest): Promise<CreateTerminalResponse> => {
-        return { terminalId: 'noop' };
-      },
-      unstable_createElicitation: async (params: CreateElicitationRequest): Promise<CreateElicitationResponse> => {
-        if (taskId && sessionId) {
-          return waitForElicitationResponse(taskId, sessionId, agent, modeId, params);
-        }
-        return { action: 'decline' };
-      },
-    };
+    return buildAcpClient(this.worktreePath, () => ({
+      taskId,
+      sessionId,
+      modeId,
+      agent,
+      onSessionUpdate: (params) => this.handleSessionUpdate(params),
+    }));
   }
 }
 
@@ -282,8 +171,12 @@ export async function dispatchViaAcp(opts: AcpDispatchOpts): Promise<AcpDispatch
     broker,
   } = opts;
 
-  const args = resolveAcpSpawnArgs(agent);
-  if (!args) {
+  // v2.3 phase 3: launch from the resolved registry def (config override /
+  // custom-ACP command) with the built-in switch as the fallback. The dispatcher
+  // passes `resolved`; fall back to a registry lookup if it didn't.
+  const resolved = opts.resolved ?? getResolvedRegistry().get(agent);
+  const spec = resolved ? resolveLaunchSpec(resolved, installPath ?? null) : null;
+  if (!spec) {
     return {
       exitCode: 1,
       output: `Agent '${agent}' does not support ACP.`,
@@ -293,12 +186,11 @@ export async function dispatchViaAcp(opts: AcpDispatchOpts): Promise<AcpDispatch
     };
   }
 
-  const binary = installPath ?? agent;
-  log.info({ agent, binary, worktreePath, modeId, model: opts.model }, 'acp-dispatch: spawning');
-  const child = spawn(binary, args, {
+  log.info({ agent, binary: spec.binary, worktreePath, modeId, model: opts.model }, 'acp-dispatch: spawning');
+  const child = spawn(spec.binary, spec.args, {
     cwd: worktreePath,
     stdio: ['pipe', 'pipe', 'pipe'],
-    env: { ...process.env },
+    env: { ...process.env, ...spec.env },
   });
 
   const streamCtx = new AcpStreamContext(

apps/coder/src/services/acp-event-map.ts

@@ -0,0 +1,68 @@
+/**
+ * Shared ACP session-update → normalized AgentEvent mapping.
+ *
+ * Extracted verbatim (v2.6 Phase 2) from `AcpStreamContext.handleSessionUpdate`
+ * in `acp-dispatch.ts` so the warm ACP backend (`backends/warm-acp.ts`) and the
+ * one-shot dispatch share ONE mapping. The one-shot path translates the returned
+ * events into broker frames itself (preserving its prior behavior byte-for-byte);
+ * the warm backend forwards them to the dispatcher's `ctx.onEvent` exactly like
+ * the opencode-server backend does. No I/O, no broker — pure, so it's unit-testable.
+ *
+ * Spec: openspec/changes/v2-6-persistent-agent-sessions/design.md §2b.
+ */
+import type { SessionNotification } from '@agentclientprotocol/sdk';
+import type { AgentEvent } from './agent-backend.js';
+import { type AcpToolSnapshot, mergeToolSnapshot } from './acp-tool-snapshot.js';
+
+/**
+ * Map one ACP `session/update` notification to zero-or-more normalized AgentEvents.
+ *
+ * `priorSnapshots` is the caller-owned tool-call snapshot accumulator (toolCallId →
+ * snapshot). For `tool_call` / `tool_call_update` the merged snapshot is written
+ * back into it (mutated in place, mirroring `AcpStreamContext.handleToolUpdate`)
+ * so a later `tool_call_update` merges over the earlier `tool_call`. Pass an empty
+ * Map for a stateless single call.
+ *
+ * Returns an array (never throws) so the caller can splat it onto `onEvent`.
+ */
+export function mapSessionUpdate(
+  params: SessionNotification,
+  priorSnapshots: Map<string, AcpToolSnapshot> = new Map(),
+): AgentEvent[] {
+  const update = params.update;
+  switch (update.sessionUpdate) {
+    case 'agent_message_chunk': {
+      const content = update.content;
+      if (content.type === 'text' && 'text' in content) {
+        return [{ type: 'text', text: (content as { text: string }).text }];
+      }
+      return [];
+    }
+    case 'agent_thought_chunk': {
+      const content = update.content;
+      if (content.type === 'text' && 'text' in content) {
+        return [{ type: 'reasoning', text: (content as { text: string }).text }];
+      }
+      return [];
+    }
+    case 'tool_call': {
+      const snapshot = mergeToolSnapshot(update.toolCallId, update, priorSnapshots.get(update.toolCallId));
+      priorSnapshots.set(update.toolCallId, snapshot);
+      return [{ type: 'tool_call', toolCall: snapshot }];
+    }
+    case 'tool_call_update': {
+      const snapshot = mergeToolSnapshot(update.toolCallId, update, priorSnapshots.get(update.toolCallId));
+      priorSnapshots.set(update.toolCallId, snapshot);
+      return [{ type: 'tool_update', toolCall: snapshot }];
+    }
+    case 'available_commands_update': {
+      const commands = update.availableCommands.map((cmd) => ({
+        name: cmd.name,
+        description: cmd.description ?? undefined,
+      }));
+      return [{ type: 'commands', commands }];
+    }
+    default:
+      return [];
+  }
+}

apps/coder/src/services/acp-probe.ts

@@ -130,6 +130,17 @@ export async function probeAcpProvider(
     });
 
     const session = await connection.newSession({ cwd, mcpServers: [] });
+    // available_commands_update is an async session notification opencode sends
+    // shortly AFTER newSession resolves — reading probedCommands synchronously
+    // here races it and captures nothing. Wait briefly for the first batch, then
+    // a short settle for any stragglers (capped well under PROBE_TIMEOUT_MS).
+    const deadline = Date.now() + 3_000;
+    while (probedCommands.length === 0 && Date.now() < deadline) {
+      await new Promise((r) => setTimeout(r, 150));
+    }
+    if (probedCommands.length > 0) {
+      await new Promise((r) => setTimeout(r, 300));
+    }
     const result = parseSessionResponse(session, agent);
     result.commands = probedCommands;
     await connection.closeSession({ sessionId: session.sessionId }).catch(() => {});

apps/coder/src/services/acp-spawn.ts

@@ -1,15 +1,15 @@
+import type { ResolvedProviderDef } from './provider-config-registry.js';
+
 /**
- * Resolve ACP spawn argv per provider (host-probe verified 2026-05-25).
+ * Resolve ACP spawn argv per built-in provider (host-probe verified 2026-05-25).
+ * Source of truth for built-in default argv — resolveLaunchSpec wraps these; it
+ * does NOT replace them.
  */
 export function resolveAcpSpawnArgs(agent: string): string[] | null {
   switch (agent) {
     case 'opencode':
     case 'goose':
       return ['acp'];
-    case 'cursor':
-      return ['acp'];
-    case 'copilot':
-      return ['--acp'];
     case 'qwen':
       return ['--acp'];
     default:
@@ -17,13 +17,34 @@ export function resolveAcpSpawnArgs(agent: string): string[] | null {
   }
 }
 
-export function resolveAcpProbeBinaries(agent: string): string[] {
-  switch (agent) {
-    case 'cursor':
-      return ['cursor-agent', 'agent'];
-    case 'copilot':
-      return ['copilot'];
-    default:
-      return [agent];
+/**
+ * v2.3 phase 3: resolve the launch spec for an ACP dispatch (design.md §5.1).
+ * Consults the resolved registry's launchCommand (config override or custom-ACP
+ * entry) first; otherwise falls back to the built-in default argv above.
+ *
+ * Byte-identical to pre-v2.3 for built-ins with no override: binary is
+ * `installPath ?? id` and args come from resolveAcpSpawnArgs — exactly the
+ * `binary = installPath ?? agent` + `resolveAcpSpawnArgs(agent)` the dispatcher
+ * used before. (Deliberate deviation from design §5.1's `!installPath → null`:
+ * the old path spawned the bare agent name when install_path was missing, so we
+ * preserve the `?? id` fallback rather than fail.)
+ */
+export function resolveLaunchSpec(
+  resolved: ResolvedProviderDef,
+  installPath: string | null,
+): { binary: string; args: string[]; env?: Record<string, string> } | null {
+  if (resolved.launchCommand) {
+    return {
+      binary: resolved.launchCommand[0],
+      args: resolved.launchCommand.slice(1),
+      env: resolved.env,
+    };
   }
+  const args = resolveAcpSpawnArgs(resolved.id);
+  if (!args) return null;
+  return { binary: installPath ?? resolved.id, args, env: resolved.env };
+}
+
+export function resolveAcpProbeBinaries(agent: string): string[] {
+  return [agent];
 }

apps/coder/src/services/acp-stream.ts

@@ -2,7 +2,7 @@ import { Readable, Writable } from 'node:stream';
 import type { ChildProcess } from 'node:child_process';
 import { ndJsonStream } from '@agentclientprotocol/sdk';
 
-export function nodeReadableToWeb(nodeStream: NodeJS.ReadableStream): ReadableStream<Uint8Array> {
+function nodeReadableToWeb(nodeStream: NodeJS.ReadableStream): ReadableStream<Uint8Array> {
   return new ReadableStream<Uint8Array>({
     start(controller) {
       nodeStream.on('data', (chunk: Buffer) => controller.enqueue(new Uint8Array(chunk)));
@@ -17,7 +17,7 @@ export function nodeReadableToWeb(nodeStream: NodeJS.ReadableStream): ReadableSt
   });
 }
 
-export function nodeWritableToWeb(nodeStream: NodeJS.WritableStream): WritableStream<Uint8Array> {
+function nodeWritableToWeb(nodeStream: NodeJS.WritableStream): WritableStream<Uint8Array> {
   return new WritableStream<Uint8Array>({
     write(chunk) {
       return new Promise<void>((resolve, reject) => {

apps/coder/src/services/agent-backend.ts

@@ -0,0 +1,125 @@
+/**
+ * v2.6 — AgentBackend abstraction (Phase 0 scaffold; types only, zero runtime logic).
+ *
+ * The core abstraction for persistent agent sessions. Two implementations land
+ * later: `OpenCodeServerBackend` (Phase 1, opencode HTTP server) and
+ * `WarmAcpBackend` (Phase 2, long-lived ACP process). Backends emit
+ * transport-agnostic `AgentEvent`s; the dispatcher maps them to WS frames.
+ *
+ * Nothing imports this file yet — it must compile standalone.
+ * Spec: openspec/changes/v2-6-persistent-agent-sessions/design.md §2.
+ */
+import type { AcpToolSnapshot } from './acp-tool-snapshot.js';
+import type { AgentCommand } from './provider-types.js';
+
+/** Backend transport kind. Mirrors `agent_sessions.backend` CHECK in schema.sql. */
+export type AgentBackendKind = 'opencode_server' | 'acp_warm' | 'claude_sdk';
+
+/**
+ * Normalized, transport-agnostic events a backend emits during a turn (§2).
+ * Derived from acp-dispatch's session-update handling, but WITHOUT the WS
+ * envelope (message_id/chat_id) — the dispatcher owns frame mapping.
+ *
+ * `tool_call` vs `tool_update` are kept distinct on purpose: acp-dispatch
+ * currently merges both into one snapshot frame, but opencode's SSE
+ * distinguishes tool-start from tool-result, so the contract carries both.
+ * `commands` mirrors the ACP `available_commands_update` path (v2.5.10).
+ */
+export type AgentEvent =
+  | { type: 'text'; text: string }
+  | { type: 'reasoning'; text: string }
+  | { type: 'tool_call'; toolCall: AcpToolSnapshot }
+  | { type: 'tool_update'; toolCall: AcpToolSnapshot }
+  | { type: 'commands'; commands: AgentCommand[] };
+
+/** Params to establish (or look up) a backend session (§2). */
+export interface EnsureSessionOpts {
+  agent: string;
+  /** Resolved model id. */
+  model: string;
+  /** P1.5-b: the chat (tab) this turn belongs to. agent_sessions is keyed
+   *  (chat_id, agent) — the tab/chat is the context unit. Always non-null:
+   *  the dispatcher creates a chat for session-less tasks before calling. */
+  chatId: string;
+  /** Shared per-session worktree (one per `sessions.id`, not per pane). */
+  worktreePath: string;
+  /** P1.5-b: the `worktrees.id` for this session's worktree — stored on the
+   *  agent_sessions row informationally (NOT the key). */
+  worktreeId: string;
+  projectId: string;
+}
+
+/** Opaque handle to a live backend session, persisted to `agent_sessions` (§2). */
+export interface AgentSessionHandle {
+  sessionId: string;
+  agent: string;
+  backend: AgentBackendKind;
+  /** P1.5-b: the chat (tab) this session is keyed on (with agent). */
+  chatId: string;
+  /** P1.5-b: the worktree this session's chat runs in (informational link). */
+  worktreeId: string;
+  /** Provider's own session id (resume token); null until the backend assigns one. */
+  agentSessionId: string | null;
+  /** opencode HTTP server port; null for ACP backends. */
+  serverPort: number | null;
+}
+
+/** Per-turn context passed to `prompt` (§2). */
+export interface PromptCtx {
+  worktreePath: string;
+  model: string;
+  signal: AbortSignal;
+  onEvent: (e: AgentEvent) => void;
+  /** Phase 2: per-turn task id, so a warm ACP backend can route permission /
+   *  elicitation prompts back to the UI via the permission-waiter. Optional —
+   *  the opencode-server backend (autonomous) ignores it. */
+  taskId?: string;
+  /** Phase 2: per-turn mode id (gates autonomous mode in the permission-waiter). */
+  modeId?: string;
+}
+
+/** Result of a completed turn (§2). Diff/persist happen outside the backend. */
+export interface TurnResult {
+  ok: boolean;
+  error?: string;
+  // Optional context-window telemetry (claude SDK): the model's reported window
+  // (ctxMax, 1M-aware) and the peak request input ≈ current fill (ctxUsed). The
+  // dispatcher writes these onto the assistant message so the ContextBar renders a
+  // real fill for the turn. Omitted by backends that don't report a window.
+  ctxUsed?: number;
+  ctxMax?: number;
+}
+
+/**
+ * The core backend abstraction (§2). Implementations: OpenCodeServerBackend
+ * (Phase 1), WarmAcpBackend (Phase 2).
+ */
+export interface AgentBackend {
+  /** Lazy: spawn server / warm process if not already up for this (session, agent). §2 */
+  ensureSession(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle>;
+  /** Send a prompt; stream events via ctx.onEvent; resolves when the turn completes. §2 */
+  prompt(handle: AgentSessionHandle, input: string, ctx: PromptCtx): Promise<TurnResult>;
+  /** Graceful teardown of one session (session close or idle timeout). §2 */
+  closeSession(handle: AgentSessionHandle): Promise<void>;
+  /** Full teardown — kills all spawned servers/processes. §2 */
+  dispose(): Promise<void>;
+  /** Liveness for health endpoint + dispatcher fallback decision. §2 */
+  health(): 'up' | 'down';
+  /**
+   * v2.6 Phase 3: true iff a turn is in flight on this backend. The pool's idle
+   * eviction + LRU cap NEVER evict a busy backend (design §6 busy rule); the
+   * health-monitor defers a restart while busy (stale-grace). Optional so the
+   * Phase-0 scaffold and any test double stay compatible — absent ⇒ treated as
+   * not busy. opencode-server (multi-session) is busy iff ANY session has an
+   * active turn; warm-acp (single session) iff its one slot is active.
+   */
+  isBusy?(): boolean;
+  /**
+   * v2.6 Phase 3: optional proactive health probe + busy-aware self-restart, run
+   * by the pool's periodic sweep. The opencode-server backend implements it
+   * (detects a hung-but-not-exited server and restarts when non-busy). Backends
+   * with no long-lived shared process (warm-ACP recovers lazily on its own child
+   * exit) can omit it. Must never throw — the sweep ignores rejections.
+   */
+  tickHealth?(now?: number): Promise<void>;
+}

apps/coder/src/services/agent-pool.ts

@@ -0,0 +1,246 @@
+/**
+ * v2.6 — AgentPool.
+ *
+ * Lazy get-or-create registry of `AgentBackend` instances keyed by
+ * `${primary}:${agent}` (primary = chatId for warm-ACP, a fixed sentinel for the
+ * single shared opencode server). Phase 0 shipped the skeleton (Map + health +
+ * dispose). Phase 3 adds the LIFECYCLE: per-entry idle tracking, a periodic
+ * idle-TTL + LRU-cap sweep (the pure decisions live in
+ * `backends/lifecycle-decisions.ts`), and a `closeChat` helper for the chat-close
+ * hook. Reattach after eviction is implicit — the next turn's `ensureSession`
+ * rebuilds the backend from `agent_sessions` / `worktrees` (DB is the source of
+ * truth; the in-memory pool is a warm cache).
+ *
+ * The hard rule (design §6): NEVER evict a busy backend (one with an in-flight
+ * turn). `selectIdleEvictionTargets` / `selectLruEvictionTargets` enforce it via
+ * `backend.isBusy()`; a long turn that outlives the TTL is left alone.
+ *
+ * Spec: openspec/changes/v2-6-persistent-agent-sessions/design.md §2 / §6.
+ */
+import type { FastifyBaseLogger } from 'fastify';
+import type { AgentBackend } from './agent-backend.js';
+import {
+  selectIdleEvictionTargets,
+  selectLruEvictionTargets,
+  DEFAULT_IDLE_TTL_MS,
+  DEFAULT_MAX_LIVE_BACKENDS,
+} from './backends/lifecycle-decisions.js';
+
+interface PoolEntry {
+  primary: string;
+  agent: string;
+  backend: AgentBackend;
+  /** Epoch ms of the last turn boundary (register or touch). Drives idle/LRU. */
+  lastActiveAt: number;
+}
+
+export interface AgentPoolOpts {
+  /** Idle TTL before a non-busy backend is evicted. Default 30 min. */
+  idleTtlMs?: number;
+  /** Max live backends before the LRU cap evicts the least-recently-used. */
+  maxLive?: number;
+  /** Sweep cadence. Default 60s (mirrors the server's periodic sweeper). */
+  sweepIntervalMs?: number;
+  log?: FastifyBaseLogger;
+}
+
+const DEFAULT_SWEEP_INTERVAL_MS = 60_000;
+
+export class AgentPool {
+  private readonly backends = new Map<string, PoolEntry>();
+  private idleTtlMs: number;
+  private maxLive: number;
+  private sweepIntervalMs: number;
+  private log: FastifyBaseLogger | undefined;
+  private sweepTimer: ReturnType<typeof setInterval> | null = null;
+  /** Serializes sweep runs so a slow eviction can't overlap the next tick. */
+  private sweeping = false;
+
+  constructor(opts: AgentPoolOpts = {}) {
+    this.idleTtlMs = opts.idleTtlMs ?? DEFAULT_IDLE_TTL_MS;
+    this.maxLive = opts.maxLive ?? DEFAULT_MAX_LIVE_BACKENDS;
+    this.sweepIntervalMs = opts.sweepIntervalMs ?? DEFAULT_SWEEP_INTERVAL_MS;
+    this.log = opts.log;
+  }
+
+  /** Apply env-derived knobs to the module singleton at bootstrap (before
+   *  startReaper). Only overrides explicitly-provided fields. */
+  configure(opts: AgentPoolOpts): void {
+    if (opts.idleTtlMs != null) this.idleTtlMs = opts.idleTtlMs;
+    if (opts.maxLive != null) this.maxLive = opts.maxLive;
+    if (opts.sweepIntervalMs != null) this.sweepIntervalMs = opts.sweepIntervalMs;
+    if (opts.log) this.log = opts.log;
+  }
+
+  private key(primary: string, agent: string): string {
+    return `${primary}:${agent}`;
+  }
+
+  /** Map lookup only. Spawning happens in the dispatcher (Phase 1/2). A hit also
+   *  marks the entry recently-active so a resolve-without-prompt doesn't get it
+   *  evicted out from under an imminent turn. */
+  get(primary: string, agent: string): AgentBackend | undefined {
+    const entry = this.backends.get(this.key(primary, agent));
+    if (entry) entry.lastActiveAt = Date.now();
+    return entry?.backend;
+  }
+
+  /** Store a backend instance for this (primary, agent). */
+  register(primary: string, agent: string, backend: AgentBackend): void {
+    this.backends.set(this.key(primary, agent), { primary, agent, backend, lastActiveAt: Date.now() });
+  }
+
+  /** Mark a backend recently-active (call at turn start AND settle so a long turn
+   *  keeps its slot warm). No-op if the key isn't pooled. */
+  touch(primary: string, agent: string): void {
+    const entry = this.backends.get(this.key(primary, agent));
+    if (entry) entry.lastActiveAt = Date.now();
+  }
+
+  /** Snapshot for the decision helpers (busy is read live from the backend). */
+  private snapshots(): { key: string; lastActiveAt: number; busy: boolean }[] {
+    const out: { key: string; lastActiveAt: number; busy: boolean }[] = [];
+    for (const [key, e] of this.backends) {
+      out.push({ key, lastActiveAt: e.lastActiveAt, busy: e.backend.isBusy?.() ?? false });
+    }
+    return out;
+  }
+
+  /** Summary for the health endpoint. */
+  health(): { size: number; busy: number } {
+    let busy = 0;
+    for (const e of this.backends.values()) if (e.backend.isBusy?.()) busy++;
+    return { size: this.backends.size, busy };
+  }
+
+  // ─── Phase 3: idle-TTL + LRU eviction sweep ──────────────────────────────────
+
+  /** Start the periodic idle + LRU sweep. Idempotent; unref'd so it never holds
+   *  the process open on its own. */
+  startReaper(log?: FastifyBaseLogger): void {
+    if (log) this.log = log;
+    if (this.sweepTimer) return;
+    this.sweepTimer = setInterval(() => {
+      void this.sweep().catch((err) => {
+        this.log?.warn({ err: errMsg(err) }, 'agent-pool: sweep error');
+      });
+    }, this.sweepIntervalMs);
+    this.sweepTimer.unref?.();
+  }
+
+  stopReaper(): void {
+    if (this.sweepTimer) {
+      clearInterval(this.sweepTimer);
+      this.sweepTimer = null;
+    }
+  }
+
+  /**
+   * One sweep pass: evict idle-past-TTL backends, then enforce the LRU cap.
+   * Deduped (a key can't appear in both lists for one pass). Busy backends are
+   * excluded by the decision helpers — a live turn is never torn down.
+   */
+  async sweep(now: number = Date.now()): Promise<{ evicted: string[] }> {
+    if (this.sweeping) return { evicted: [] };
+    this.sweeping = true;
+    try {
+      // Phase 3: drive each backend's optional proactive health probe first (the
+      // opencode server's busy-aware hung-detect + self-restart). Best-effort —
+      // a probe must never fail the sweep.
+      for (const e of this.backends.values()) {
+        if (e.backend.tickHealth) {
+          await e.backend.tickHealth(now).catch((err) => {
+            this.log?.warn({ key: this.key(e.primary, e.agent), err: errMsg(err) }, 'agent-pool: tickHealth threw');
+          });
+        }
+      }
+      const snaps = this.snapshots();
+      const idle = selectIdleEvictionTargets(snaps, now, this.idleTtlMs);
+      // LRU runs on what remains after idle eviction, so the two never double-evict.
+      const idleSet = new Set(idle);
+      const remaining = snaps.filter((s) => !idleSet.has(s.key));
+      const lru = selectLruEvictionTargets(remaining, this.maxLive);
+      const targets = [...idle, ...lru];
+      if (targets.length === 0) return { evicted: [] };
+
+      const evicted: string[] = [];
+      for (const key of targets) {
+        const entry = this.backends.get(key);
+        if (!entry) continue;
+        // Re-check busy right before teardown — a turn may have started since the
+        // snapshot. Defensive; the decision already excluded busy at snapshot time.
+        if (entry.backend.isBusy?.()) continue;
+        this.backends.delete(key);
+        try {
+          await entry.backend.dispose();
+        } catch (err) {
+          this.log?.warn({ key, err: errMsg(err) }, 'agent-pool: backend dispose threw during eviction');
+        }
+        evicted.push(key);
+      }
+      if (evicted.length > 0) {
+        this.log?.info({ evicted, size: this.backends.size }, 'agent-pool: evicted idle/over-cap backends');
+      }
+      return { evicted };
+    } finally {
+      this.sweeping = false;
+    }
+  }
+
+  // ─── Phase 3: chat-close cleanup (3.3) ───────────────────────────────────────
+
+  /**
+   * Tear down every pooled backend whose key is for this chat. Used by the
+   * chat-close hook. The opencode server is shared (keyed on a sentinel, not the
+   * chat), so it is NOT disposed here — only its session is closed via
+   * `closeSession`, which the hook calls directly with the per-(chat,agent)
+   * handle. Returns the keys it removed. Skips busy entries (a close mid-turn is
+   * rare but must not kill a live stream — the idle sweep reaps it shortly after).
+   */
+  async closeChat(chatId: string): Promise<string[]> {
+    const removed: string[] = [];
+    const prefix = `${chatId}:`;
+    for (const [key, entry] of [...this.backends]) {
+      if (!key.startsWith(prefix)) continue;
+      if (entry.backend.isBusy?.()) continue;
+      this.backends.delete(key);
+      try {
+        await entry.backend.dispose();
+      } catch (err) {
+        this.log?.warn({ key, err: errMsg(err) }, 'agent-pool: dispose threw during closeChat');
+      }
+      removed.push(key);
+    }
+    return removed;
+  }
+
+  /** Look up a backend by exact key without bumping its activity (for closeSession). */
+  peek(primary: string, agent: string): AgentBackend | undefined {
+    return this.backends.get(this.key(primary, agent))?.backend;
+  }
+
+  /** Dispose every backend and clear the map. Tolerates throwing backends. */
+  async dispose(): Promise<void> {
+    this.stopReaper();
+    const entries = [...this.backends.values()];
+    this.backends.clear();
+    await Promise.allSettled(entries.map((e) => e.backend.dispose()));
+  }
+}
+
+function errMsg(e: unknown): string {
+  return e instanceof Error ? e.message : String(e);
+}
+
+/**
+ * The shared opencode server is pooled under a FIXED sentinel (one server per
+ * BooCoder process, multiplexing all opencode sessions internally) rather than a
+ * chat id — so it is NOT torn down by `closeChat(chatId)` (only its per-chat
+ * session is closed). Exported so the dispatcher + the lifecycle close-hook agree
+ * on the key without drift.
+ */
+export const OPENCODE_POOL_KEY = '__opencode_server__';
+
+/** Single shared instance — registered by the dispatcher, swept + drained by the
+ *  server's onClose hook. */
+export const agentPool = new AgentPool();

apps/coder/src/services/agent-probe.ts

@@ -1,24 +1,34 @@
 import type { Sql } from '../db.js';
 import type { FastifyBaseLogger } from 'fastify';
-import { exec as execCb } from 'node:child_process';
+import { exec as execCb, execFile as execFileCb } from 'node:child_process';
 import { promisify } from 'node:util';
-import { PROVIDERS_BY_NAME, PROBED_AGENT_NAMES } from './provider-registry.js';
+import { PROVIDERS_BY_NAME } from './provider-registry.js';
 import { resolveAcpProbeBinaries } from './acp-spawn.js';
-import { clearProviderSnapshotCache } from './provider-snapshot.js';
+import { clearProviderSnapshotCache, fetchLlamaSwapModels, prefixLlamaSwapModels } from './provider-snapshot.js';
 import { readQwenSettingsModels } from './qwen-settings.js';
+import { loadConfig } from '../config.js';
+import { loadProviderConfig } from './provider-config-registry.js';
 
 const exec = promisify(execCb);
+const execFile = promisify(execFileCb);
+
+// `which` via execFile (no shell) — the binary name can come from the config
+// file (custom ACP entries), so avoid interpolating it into a shell string.
+async function whichBinary(bin: string): Promise<string | null> {
+  try {
+    const { stdout } = await execFile('which', [bin], { timeout: 10_000 });
+    const path = stdout.trim();
+    return path || null;
+  } catch {
+    return null;
+  }
+}
 
 async function resolveInstallPath(agentName: string): Promise<string | null> {
   const candidates = resolveAcpProbeBinaries(agentName);
   for (const bin of candidates) {
-    try {
-      const { stdout } = await exec(`which ${bin}`, { timeout: 10_000 });
-      const path = stdout.trim();
-      if (path) return path;
-    } catch {
-      /* try next */
-    }
+    const path = await whichBinary(bin);
+    if (path) return path;
   }
   return null;
 }
@@ -27,15 +37,6 @@ async function detectAcpSupport(agentName: string, installPath: string): Promise
   const transport = PROVIDERS_BY_NAME.get(agentName)?.transport;
   if (transport !== 'acp') return false;
 
-  if (agentName === 'copilot') {
-    try {
-      const { stdout } = await exec(`"${installPath}" --help`, { timeout: 10_000 });
-      return stdout.includes('--acp');
-    } catch {
-      return false;
-    }
-  }
-
   if (agentName === 'qwen') {
     try {
       const { stdout } = await exec(`"${installPath}" --help`, { timeout: 10_000 });
@@ -55,14 +56,37 @@ async function detectAcpSupport(agentName: string, installPath: string): Promise
 
 /**
  * Probe for available agents on the HOST.
+ *
+ * v2.3: iterates the resolved provider registry (built-ins + config-backed
+ * custom ACP entries) rather than the hardcoded `PROBED_AGENT_NAMES`. Native
+ * boocode is not probed; disabled providers are skipped (their `available_agents`
+ * row is kept, not deleted). `enabled` is read from the in-memory registry only —
+ * no DB column in Phase 1 (design.md §3.3).
  */
 export async function probeAgents(sql: Sql, log: FastifyBaseLogger): Promise<void> {
   clearProviderSnapshotCache();
   log.info('agent-probe: scanning for known agents');
 
-  for (const agentName of PROBED_AGENT_NAMES) {
+  const registry = loadProviderConfig(loadConfig().CODER_PROVIDERS_PATH);
+
+  for (const resolved of registry.values()) {
+    const agentName = resolved.id;
+
+    // Native boocode is not a probed host agent.
+    if (resolved.transport === 'native') continue;
+
+    // Disabled providers: skip the probe, keep any existing row.
+    if (!resolved.enabled) {
+      log.info({ agent: agentName }, 'agent-probe: skipping disabled provider');
+      continue;
+    }
+
     try {
-      const installPath = await resolveInstallPath(agentName);
+      // Custom ACP entries resolve their binary from command[0]; built-ins use
+      // the per-agent probe binaries.
+      const installPath = resolved.isCustomAcp && resolved.launchCommand
+        ? await whichBinary(resolved.launchCommand[0])
+        : await resolveInstallPath(agentName);
       if (!installPath) continue;
 
       let version: string | null = null;
@@ -73,24 +97,43 @@ export async function probeAgents(sql: Sql, log: FastifyBaseLogger): Promise<voi
         /* optional */
       }
 
-      const providerDef = PROVIDERS_BY_NAME.get(agentName);
-      let supportsAcp = providerDef?.transport === 'acp';
-      if (supportsAcp) {
-        supportsAcp = await detectAcpSupport(agentName, installPath);
+      // Custom ACP entries are ACP by declaration; built-ins detect support.
+      let supportsAcp: boolean;
+      if (resolved.isCustomAcp) {
+        supportsAcp = true;
+      } else {
+        supportsAcp = resolved.transport === 'acp';
+        if (supportsAcp) {
+          supportsAcp = await detectAcpSupport(agentName, installPath);
+        }
       }
 
       let models: Array<{ id: string; label: string }> = [];
-      if (providerDef?.modelSource === 'static' && providerDef.staticModels) {
-        models = providerDef.staticModels;
+      if (!resolved.isCustomAcp) {
+        const providerDef = PROVIDERS_BY_NAME.get(agentName);
+        if (providerDef?.modelSource === 'static' && providerDef.staticModels) {
+          models = providerDef.staticModels;
+        }
+        if (agentName === 'qwen') {
+          models = await readQwenSettingsModels();
+        }
+        if (providerDef?.mergeLlamaSwap) {
+          try {
+            const config = loadConfig();
+            const llamaModels = prefixLlamaSwapModels(await fetchLlamaSwapModels(config));
+            models = [...models, ...llamaModels];
+          } catch (err) {
+            log.warn({ agent: agentName, err: err instanceof Error ? err.message : String(err) }, 'agent-probe: llama-swap model fetch failed (non-fatal)');
+          }
+        }
       }
 
-      if (agentName === 'qwen') {
-        models = await readQwenSettingsModels();
-      }
-
-      const label = providerDef?.label ?? agentName;
-      const transport =
-        providerDef?.transport === 'acp' && !supportsAcp ? 'pty' : (providerDef?.transport ?? 'pty');
+      const label = resolved.configLabel ?? resolved.label;
+      const transport = resolved.isCustomAcp
+        ? 'acp'
+        : resolved.transport === 'acp' && !supportsAcp
+          ? 'pty'
+          : (resolved.transport ?? 'pty');
 
       await sql`
         INSERT INTO available_agents (name, install_path, version, supports_acp, last_probed_at, models, label, transport)

apps/coder/src/services/agent-status-publish.ts

@@ -0,0 +1,55 @@
+/**
+ * agent-status-publish (#10) — builds + publishes the `agent_status_updated`
+ * WS frame on the per-session channel (the same channel CoderPane subscribes to).
+ *
+ * Kept separate from normalize-agent-status.ts so that module stays a pure,
+ * broker-free helper (trivially unit-testable; reused by the config-injection
+ * follow-on). The frame contract is pinned in apps/server/src/types/ws-frames.ts
+ * (`AgentStatusUpdatedFrame`) and mirrored byte-identical in apps/web.
+ */
+import type { Broker } from '@boocode/server/broker';
+import type { WsFrame } from '@boocode/contracts/ws-frames';
+import type { AgentStatus } from './normalize-agent-status.js';
+
+// The exact slice of Broker we need — accepting just the bound method keeps call
+// sites flexible (pass `broker.publishFrame.bind(broker)` or, since the broker's
+// publishFrame doesn't read `this`, `broker.publishFrame` directly).
+type PublishFrame = Broker['publishFrame'];
+
+/**
+ * Best-effort publish of a normalized agent status. The broker's publishFrame
+ * already fail-closes (validates + logs + drops on bad input, never throws), but
+ * we additionally swallow any unexpected error so a publish can NEVER break the
+ * turn it's reporting on.
+ *
+ * @param publishFrame  the session channel publisher (broker.publishFrame)
+ * @param sessionId     WS subscription channel (CoderPane subscribes per-session)
+ * @param chatId        the (chat) half of the (chat, agent) status key
+ * @param agent         the (agent) half of the key
+ * @param status        normalized lifecycle status
+ * @param reason        free-form discriminator (turn_start / turn_complete / …)
+ * @param at            ISO timestamp; defaults to now
+ */
+export function publishAgentStatus(
+  publishFrame: PublishFrame,
+  sessionId: string,
+  chatId: string,
+  agent: string,
+  status: AgentStatus,
+  reason?: string,
+  at: string = new Date().toISOString(),
+): void {
+  try {
+    const frame: WsFrame = {
+      type: 'agent_status_updated',
+      chat_id: chatId,
+      agent,
+      status,
+      ...(reason ? { reason } : {}),
+      at,
+    };
+    publishFrame(sessionId, frame);
+  } catch {
+    // never let a status publish break the turn — best-effort only.
+  }
+}

apps/coder/src/services/backends/__tests__/claude-sdk-map.test.ts

@@ -0,0 +1,251 @@
+import { describe, it, expect } from 'vitest';
+import type { SDKMessage } from '@anthropic-ai/claude-agent-sdk';
+import { mapSdkMessage, createClaudeSdkMapState } from '../claude-sdk-map.js';
+import type { AgentEvent } from '../../agent-backend.js';
+
+/**
+ * Pure mapper for Claude-SDK messages → AgentEvents (claude-sdk-sessionstore #9 Part 2).
+ * Verifies the partial-stream → live-delta mapping, tool assembly across blocks, and
+ * the final-assistant dedup, with no live `claude` binary involved.
+ *
+ * Messages are cast through `unknown` to `SDKMessage`: the real SDK shapes carry many
+ * fields (uuid, parent_tool_use_id, …) irrelevant to the mapper, which reads only the
+ * `type`/`event`/`message.content` it discriminates on. The cast keeps the fixtures
+ * minimal while the production code path sees the full real types (the backend's
+ * typecheck against the real SDK is the type-safety proof).
+ */
+function msg(m: unknown): SDKMessage {
+  return m as SDKMessage;
+}
+
+/** A partial-stream message wrapping one BetaRawMessageStreamEvent. */
+function streamEvent(event: unknown): SDKMessage {
+  return msg({ type: 'stream_event', event, parent_tool_use_id: null, uuid: 'u', session_id: 's' });
+}
+
+describe('mapSdkMessage — partial stream deltas', () => {
+  it('maps a text_delta to a text event', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(
+      streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text: 'Hello' } }),
+      state,
+    );
+    expect(out).toEqual<AgentEvent[]>([{ type: 'text', text: 'Hello' }]);
+  });
+
+  it('maps a thinking_delta to a reasoning event', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(
+      streamEvent({
+        type: 'content_block_delta',
+        index: 0,
+        delta: { type: 'thinking_delta', thinking: 'pondering', estimated_tokens: null },
+      }),
+      state,
+    );
+    expect(out).toEqual<AgentEvent[]>([{ type: 'reasoning', text: 'pondering' }]);
+  });
+
+  it('drops empty text/thinking deltas', () => {
+    const state = createClaudeSdkMapState();
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text: '' } }), state),
+    ).toEqual([]);
+    expect(
+      mapSdkMessage(
+        streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'thinking_delta', thinking: '', estimated_tokens: null } }),
+        state,
+      ),
+    ).toEqual([]);
+  });
+
+  it('ignores message framing + signature/citation deltas', () => {
+    const state = createClaudeSdkMapState();
+    expect(mapSdkMessage(streamEvent({ type: 'message_start', message: {} }), state)).toEqual([]);
+    expect(mapSdkMessage(streamEvent({ type: 'message_stop' }), state)).toEqual([]);
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'signature_delta', signature: 'x' } }), state),
+    ).toEqual([]);
+  });
+});
+
+describe('mapSdkMessage — tool assembly across blocks', () => {
+  it('opens a tool_call on content_block_start, buffers input_json_delta, emits tool_update with parsed input on stop', () => {
+    const state = createClaudeSdkMapState();
+
+    const started = mapSdkMessage(
+      streamEvent({
+        type: 'content_block_start',
+        index: 1,
+        content_block: { type: 'tool_use', id: 'tool-1', name: 'view_file', input: {} },
+      }),
+      state,
+    );
+    expect(started).toEqual<AgentEvent[]>([
+      { type: 'tool_call', toolCall: { toolCallId: 'tool-1', title: 'view_file', kind: null, status: 'in_progress', rawInput: {}, rawOutput: undefined } },
+    ]);
+
+    // args stream in fragments under the same block index
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 1, delta: { type: 'input_json_delta', partial_json: '{"path":' } }), state),
+    ).toEqual([]);
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 1, delta: { type: 'input_json_delta', partial_json: '"a.ts"}' } }), state),
+    ).toEqual([]);
+
+    const stopped = mapSdkMessage(streamEvent({ type: 'content_block_stop', index: 1 }), state);
+    expect(stopped).toHaveLength(1);
+    const ev = stopped[0]!;
+    expect(ev.type).toBe('tool_update');
+    if (ev.type === 'tool_update') {
+      expect(ev.toolCall.toolCallId).toBe('tool-1');
+      expect(ev.toolCall.title).toBe('view_file');
+      expect(ev.toolCall.rawInput).toEqual({ path: 'a.ts' });
+    }
+  });
+
+  it('content_block_stop for a non-tool block (no tracked index) emits nothing', () => {
+    const state = createClaudeSdkMapState();
+    // text block was streamed at index 0 but never tracked as a tool
+    mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text: 'hi' } }), state);
+    expect(mapSdkMessage(streamEvent({ type: 'content_block_stop', index: 0 }), state)).toEqual([]);
+  });
+
+  it('falls back to the prior input when the buffered tool JSON is invalid', () => {
+    const state = createClaudeSdkMapState();
+    mapSdkMessage(
+      streamEvent({ type: 'content_block_start', index: 2, content_block: { type: 'tool_use', id: 't2', name: 'grep', input: { q: 'seed' } } }),
+      state,
+    );
+    mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 2, delta: { type: 'input_json_delta', partial_json: '{not json' } }), state);
+    const stopped = mapSdkMessage(streamEvent({ type: 'content_block_stop', index: 2 }), state);
+    const ev = stopped[0]!;
+    if (ev.type === 'tool_update') {
+      expect(ev.toolCall.rawInput).toEqual({ q: 'seed' });
+    } else {
+      throw new Error('expected tool_update');
+    }
+  });
+});
+
+describe('mapSdkMessage — final assistant message', () => {
+  function assistant(content: unknown[]): SDKMessage {
+    return msg({ type: 'assistant', message: { content }, parent_tool_use_id: null, uuid: 'u', session_id: 's' });
+  }
+
+  it('dedups text/thinking (already streamed) and emits a completed tool_update per tool_use block', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(
+      assistant([
+        { type: 'text', text: 'final answer', citations: null },
+        { type: 'thinking', thinking: 'reasoned', signature: 'sig' },
+        { type: 'tool_use', id: 'tool-9', name: 'find_files', input: { glob: '**/*.ts' } },
+      ]),
+      state,
+    );
+    expect(out).toEqual<AgentEvent[]>([
+      {
+        type: 'tool_update',
+        toolCall: { toolCallId: 'tool-9', title: 'find_files', kind: null, status: 'completed', rawInput: { glob: '**/*.ts' }, rawOutput: undefined },
+      },
+    ]);
+  });
+
+  it('preserves a title from a prior partial tool_call snapshot', () => {
+    const state = createClaudeSdkMapState();
+    mapSdkMessage(
+      streamEvent({ type: 'content_block_start', index: 0, content_block: { type: 'tool_use', id: 'tool-x', name: 'view_file', input: {} } }),
+      state,
+    );
+    const out = mapSdkMessage(assistant([{ type: 'tool_use', id: 'tool-x', name: 'view_file', input: { path: 'z' } }]), state);
+    const ev = out[0]!;
+    if (ev.type === 'tool_update') {
+      expect(ev.toolCall.status).toBe('completed');
+      expect(ev.toolCall.title).toBe('view_file');
+      expect(ev.toolCall.rawInput).toEqual({ path: 'z' });
+    } else {
+      throw new Error('expected tool_update');
+    }
+  });
+});
+
+describe('mapSdkMessage — non-content messages', () => {
+  it('returns [] for system/init, status, result, and other variants', () => {
+    const state = createClaudeSdkMapState();
+    expect(mapSdkMessage(msg({ type: 'system', subtype: 'init', session_id: 's', uuid: 'u' }), state)).toEqual([]);
+    expect(mapSdkMessage(msg({ type: 'system', subtype: 'status', status: null, session_id: 's', uuid: 'u' }), state)).toEqual([]);
+    expect(
+      mapSdkMessage(msg({ type: 'result', subtype: 'success', result: 'done', session_id: 's', uuid: 'u' }), state),
+    ).toEqual([]);
+  });
+});
+
+describe('mapSdkMessage — user tool results', () => {
+  /** A `user` message carrying tool_result blocks (the SDK feeds tool output back here). */
+  function userMsg(content: unknown): SDKMessage {
+    return msg({ type: 'user', message: { role: 'user', content }, parent_tool_use_id: null, uuid: 'u', session_id: 's' });
+  }
+
+  it('maps a string tool_result to a completed tool_update carrying the output', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(userMsg([{ type: 'tool_result', tool_use_id: 't1', content: 'done' }]), state);
+    expect(out).toEqual<AgentEvent[]>([
+      {
+        type: 'tool_update',
+        toolCall: { toolCallId: 't1', title: 't1', kind: null, status: 'completed', rawInput: undefined, rawOutput: 'done' },
+      },
+    ]);
+  });
+
+  it('marks an is_error result failed', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(userMsg([{ type: 'tool_result', tool_use_id: 't1', content: 'boom', is_error: true }]), state);
+    const ev = out[0]!;
+    if (ev.type !== 'tool_update') throw new Error('expected tool_update');
+    expect(ev.toolCall.status).toBe('failed');
+    expect(ev.toolCall.rawOutput).toBe('boom');
+  });
+
+  it('flattens array text blocks (skipping non-text) and reuses a prior snapshot title', () => {
+    const state = createClaudeSdkMapState();
+    mapSdkMessage(
+      streamEvent({ type: 'content_block_start', index: 1, content_block: { type: 'tool_use', id: 't2', name: 'view_file', input: {} } }),
+      state,
+    );
+    const out = mapSdkMessage(
+      userMsg([
+        {
+          type: 'tool_result',
+          tool_use_id: 't2',
+          content: [
+            { type: 'text', text: 'line1' },
+            { type: 'image', source: {} },
+            { type: 'text', text: 'line2' },
+          ],
+        },
+      ]),
+      state,
+    );
+    const ev = out[0]!;
+    if (ev.type !== 'tool_update') throw new Error('expected tool_update');
+    expect(ev.toolCall.toolCallId).toBe('t2');
+    expect(ev.toolCall.title).toBe('view_file');
+    expect(ev.toolCall.status).toBe('completed');
+    expect(ev.toolCall.rawOutput).toBe('line1\nline2');
+  });
+
+  it('surfaces a result for an unknown tool_use_id with the id as the title', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(userMsg([{ type: 'tool_result', tool_use_id: 'orphan-id', content: 'x' }]), state);
+    expect(out[0]).toMatchObject({
+      type: 'tool_update',
+      toolCall: { toolCallId: 'orphan-id', title: 'orphan-id', kind: null, status: 'completed' },
+    });
+  });
+
+  it('ignores non-tool_result blocks and non-array content', () => {
+    const state = createClaudeSdkMapState();
+    expect(mapSdkMessage(userMsg([{ type: 'text', text: 'hi' }]), state)).toEqual([]);
+    expect(mapSdkMessage(userMsg('plain string'), state)).toEqual([]);
+  });
+});

apps/coder/src/services/backends/__tests__/claude-sdk-routing.test.ts

@@ -0,0 +1,49 @@
+import { describe, it, expect } from 'vitest';
+import { shouldUseClaudeSdk, claudeSdkBackendEnabled } from '../claude-sdk-routing.js';
+
+/**
+ * Env-flagged routing for the warm Claude-SDK backend. With CLAUDE_SDK_BACKEND off
+ * (the production default) every claude task falls through to the unchanged PTY path;
+ * with it on, only chat-tab claude tasks (session_id + chat_id) route to the SDK.
+ */
+const ON = { CLAUDE_SDK_BACKEND: '1' } as NodeJS.ProcessEnv;
+const OFF = {} as NodeJS.ProcessEnv;
+
+describe('claudeSdkBackendEnabled', () => {
+  it('is false when unset or falsy', () => {
+    expect(claudeSdkBackendEnabled({} as NodeJS.ProcessEnv)).toBe(false);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: '' } as NodeJS.ProcessEnv)).toBe(false);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: '0' } as NodeJS.ProcessEnv)).toBe(false);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: 'false' } as NodeJS.ProcessEnv)).toBe(false);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: 'off' } as NodeJS.ProcessEnv)).toBe(false);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: 'no' } as NodeJS.ProcessEnv)).toBe(false);
+  });
+
+  it('is true for any other truthy value', () => {
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: '1' } as NodeJS.ProcessEnv)).toBe(true);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: 'true' } as NodeJS.ProcessEnv)).toBe(true);
+    expect(claudeSdkBackendEnabled({ CLAUDE_SDK_BACKEND: 'on' } as NodeJS.ProcessEnv)).toBe(true);
+  });
+});
+
+describe('shouldUseClaudeSdk', () => {
+  it('is always false while the env flag is off — production claude stays on PTY', () => {
+    expect(shouldUseClaudeSdk({ agent: 'claude', session_id: 's1', chat_id: 'c1' }, OFF)).toBe(false);
+  });
+
+  it('routes a chat-tab claude task to the SDK when the flag is on', () => {
+    expect(shouldUseClaudeSdk({ agent: 'claude', session_id: 's1', chat_id: 'c1' }, ON)).toBe(true);
+  });
+
+  it('only applies to the claude agent', () => {
+    expect(shouldUseClaudeSdk({ agent: 'qwen', session_id: 's1', chat_id: 'c1' }, ON)).toBe(false);
+    expect(shouldUseClaudeSdk({ agent: 'opencode', session_id: 's1', chat_id: 'c1' }, ON)).toBe(false);
+    expect(shouldUseClaudeSdk({ agent: null, session_id: 's1', chat_id: 'c1' }, ON)).toBe(false);
+  });
+
+  it('requires both session_id and chat_id (session-less creators stay one-shot)', () => {
+    expect(shouldUseClaudeSdk({ agent: 'claude', session_id: null, chat_id: null }, ON)).toBe(false);
+    expect(shouldUseClaudeSdk({ agent: 'claude', session_id: 's1', chat_id: null }, ON)).toBe(false);
+    expect(shouldUseClaudeSdk({ agent: 'claude', session_id: null, chat_id: 'c1' }, ON)).toBe(false);
+  });
+});

apps/coder/src/services/backends/__tests__/claude-session-store.test.ts

@@ -0,0 +1,135 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import postgres from 'postgres';
+import { PostgresSessionStore } from '../claude-session-store.js';
+import type { SessionStoreEntry } from '@anthropic-ai/claude-agent-sdk';
+
+/**
+ * claude-sdk-sessionstore #9 (Part 1) — PostgresSessionStore tests.
+ *
+ * DB-opt-in (DATABASE_URL), mirrors checkpoints.test.ts: skips cleanly when the
+ * var is unset; otherwise applies the server + coder schemas and exercises the
+ * real append/load/listSessions/delete/listSubkeys round trips against postgres.
+ * Rows are namespaced under a unique project_key so concurrent suites / leftover
+ * data can't collide, and afterAll deletes everything written.
+ */
+describe.runIf(!!process.env.DATABASE_URL)('PostgresSessionStore (DB)', () => {
+  let sql: ReturnType<typeof postgres>;
+  let store: PostgresSessionStore;
+  const projectKey = `claude-store-test-${Date.now()}`;
+
+  const entry = (type: string, extra: Record<string, unknown> = {}): SessionStoreEntry => ({
+    type,
+    ...extra,
+  });
+
+  beforeAll(async () => {
+    sql = postgres(process.env.DATABASE_URL!, { max: 3 });
+    const serverSchema = resolve(__dirname, '../../../../../server/src/schema.sql');
+    const coderSchema = resolve(__dirname, '../../../schema.sql');
+    await sql.unsafe(readFileSync(serverSchema, 'utf8'));
+    await sql.unsafe(readFileSync(coderSchema, 'utf8'));
+    store = new PostgresSessionStore(sql);
+  });
+
+  afterAll(async () => {
+    if (sql) {
+      await sql`DELETE FROM claude_session_entries WHERE project_key = ${projectKey}`.catch(() => {});
+      await sql.end({ timeout: 5 });
+    }
+  });
+
+  it('append → load round-trips and preserves order across two appends', async () => {
+    const key = { projectKey, sessionId: 'sess-order' };
+    await store.append(key, [entry('user', { uuid: 'u1' }), entry('assistant', { uuid: 'a1' })]);
+    await store.append(key, [entry('result', { uuid: 'r1' })]);
+
+    const loaded = await store.load(key);
+    expect(loaded).not.toBeNull();
+    expect(loaded!.map((e) => e.uuid)).toEqual(['u1', 'a1', 'r1']);
+    expect(loaded!.map((e) => e.type)).toEqual(['user', 'assistant', 'result']);
+  });
+
+  it('append with an empty batch is a no-op (load still null for an otherwise-unseen key)', async () => {
+    const key = { projectKey, sessionId: 'sess-empty' };
+    await store.append(key, []);
+    expect(await store.load(key)).toBeNull();
+  });
+
+  it('load of a key that was never written returns null', async () => {
+    expect(await store.load({ projectKey, sessionId: 'never-seen' })).toBeNull();
+  });
+
+  it('isolates the main transcript from a subpath (load each independently)', async () => {
+    const sessionId = 'sess-subpath';
+    const mainKey = { projectKey, sessionId };
+    const subKey = { projectKey, sessionId, subpath: 'subagents/x' };
+
+    await store.append(mainKey, [entry('user', { uuid: 'main-1' })]);
+    await store.append(subKey, [entry('assistant', { uuid: 'sub-1' })]);
+
+    const main = await store.load(mainKey);
+    const sub = await store.load(subKey);
+    expect(main!.map((e) => e.uuid)).toEqual(['main-1']);
+    expect(sub!.map((e) => e.uuid)).toEqual(['sub-1']);
+  });
+
+  it('listSessions returns the session with a numeric mtime (main transcripts only)', async () => {
+    const sessionId = 'sess-list';
+    await store.append({ projectKey, sessionId }, [entry('user', { uuid: 'l1' })]);
+    // A subagent-only session must NOT surface as a main-transcript session.
+    await store.append(
+      { projectKey, sessionId: 'sess-sub-only', subpath: 'subagents/y' },
+      [entry('user', { uuid: 's1' })],
+    );
+
+    const sessions = await store.listSessions(projectKey);
+    const ids = sessions.map((s) => s.sessionId);
+    expect(ids).toContain(sessionId);
+    expect(ids).not.toContain('sess-sub-only');
+
+    const row = sessions.find((s) => s.sessionId === sessionId)!;
+    expect(typeof row.mtime).toBe('number');
+    expect(Number.isFinite(row.mtime)).toBe(true);
+    expect(row.mtime).toBeGreaterThan(0);
+  });
+
+  it('delete with a subpath removes only that subpath', async () => {
+    const sessionId = 'sess-del-subpath';
+    const mainKey = { projectKey, sessionId };
+    const subKey = { projectKey, sessionId, subpath: 'subagents/z' };
+    await store.append(mainKey, [entry('user', { uuid: 'keep-1' })]);
+    await store.append(subKey, [entry('assistant', { uuid: 'drop-1' })]);
+
+    await store.delete(subKey);
+
+    expect(await store.load(subKey)).toBeNull();
+    expect((await store.load(mainKey))!.map((e) => e.uuid)).toEqual(['keep-1']);
+  });
+
+  it('delete without a subpath removes the whole session (all subpaths)', async () => {
+    const sessionId = 'sess-del-all';
+    const mainKey = { projectKey, sessionId };
+    const subKey = { projectKey, sessionId, subpath: 'subagents/w' };
+    await store.append(mainKey, [entry('user', { uuid: 'm' })]);
+    await store.append(subKey, [entry('assistant', { uuid: 's' })]);
+
+    await store.delete({ projectKey, sessionId });
+
+    expect(await store.load(mainKey)).toBeNull();
+    expect(await store.load(subKey)).toBeNull();
+    expect(await store.listSubkeys({ projectKey, sessionId })).toEqual([]);
+  });
+
+  it('listSubkeys returns the distinct non-main subpaths', async () => {
+    const sessionId = 'sess-subkeys';
+    await store.append({ projectKey, sessionId }, [entry('user', { uuid: 'main' })]);
+    await store.append({ projectKey, sessionId, subpath: 'subagents/a' }, [entry('user', { uuid: 'a1' })]);
+    await store.append({ projectKey, sessionId, subpath: 'subagents/a' }, [entry('user', { uuid: 'a2' })]);
+    await store.append({ projectKey, sessionId, subpath: 'subagents/b' }, [entry('user', { uuid: 'b1' })]);
+
+    const subkeys = await store.listSubkeys({ projectKey, sessionId });
+    expect(subkeys.sort()).toEqual(['subagents/a', 'subagents/b']);
+  });
+});

apps/coder/src/services/backends/__tests__/lifecycle-decisions.test.ts

@@ -0,0 +1,176 @@
+import { describe, it, expect } from 'vitest';
+import {
+  selectIdleEvictionTargets,
+  selectLruEvictionTargets,
+  decideRestart,
+  selectOrphanWorktreeTargets,
+  DEFAULT_IDLE_TTL_MS,
+  DEFAULT_MAX_LIVE_BACKENDS,
+  type PoolEntrySnapshot,
+} from '../lifecycle-decisions.js';
+
+/**
+ * v2.6 Phase 3 — pure lifecycle decisions. No DB, no children, no timers; `now`
+ * is injected. Models prune.ts:selectPruneTargets — the caller acts on the keys.
+ */
+
+const NOW = 1_000_000_000_000;
+
+function entry(key: string, ageMs: number, busy = false): PoolEntrySnapshot {
+  return { key, lastActiveAt: NOW - ageMs, busy };
+}
+
+describe('selectIdleEvictionTargets (3.1)', () => {
+  it('evicts entries idle past the TTL', () => {
+    const entries = [
+      entry('a:opencode', DEFAULT_IDLE_TTL_MS + 1),
+      entry('b:goose', DEFAULT_IDLE_TTL_MS - 1),
+    ];
+    expect(selectIdleEvictionTargets(entries, NOW)).toEqual(['a:opencode']);
+  });
+
+  it('never evicts a busy entry even when idle past the TTL', () => {
+    const entries = [entry('a:opencode', DEFAULT_IDLE_TTL_MS * 10, /* busy */ true)];
+    expect(selectIdleEvictionTargets(entries, NOW)).toEqual([]);
+  });
+
+  it('respects a custom TTL', () => {
+    const entries = [entry('a:goose', 5_000), entry('b:qwen', 500)];
+    expect(selectIdleEvictionTargets(entries, NOW, 1_000)).toEqual(['a:goose']);
+  });
+
+  it('treats exactly-at-TTL as evictable (>=)', () => {
+    expect(selectIdleEvictionTargets([entry('a:x', 1_000)], NOW, 1_000)).toEqual(['a:x']);
+  });
+
+  it('returns empty for an empty pool', () => {
+    expect(selectIdleEvictionTargets([], NOW)).toEqual([]);
+  });
+});
+
+describe('selectLruEvictionTargets (3.4)', () => {
+  it('returns nothing when at or under the cap', () => {
+    const entries = [entry('a:x', 10), entry('b:y', 20)];
+    expect(selectLruEvictionTargets(entries, 2)).toEqual([]);
+    expect(selectLruEvictionTargets(entries, 5)).toEqual([]);
+  });
+
+  it('evicts the least-recently-used beyond the cap', () => {
+    // oldest first: c (300ms ago) is LRU, then a (100ms), then b (10ms).
+    const entries = [entry('a:x', 100), entry('b:y', 10), entry('c:z', 300)];
+    expect(selectLruEvictionTargets(entries, 2)).toEqual(['c:z']);
+  });
+
+  it('evicts multiple LRU entries to reach the cap', () => {
+    const entries = [
+      entry('a:x', 100),
+      entry('b:y', 10),
+      entry('c:z', 300),
+      entry('d:w', 200),
+    ];
+    // cap 1: must remove 3, oldest-first c(300), d(200), a(100).
+    expect(selectLruEvictionTargets(entries, 1)).toEqual(['c:z', 'd:w', 'a:x']);
+  });
+
+  it('never evicts a busy entry even if it is the LRU', () => {
+    // c is LRU but busy → it cannot be evicted; fall to the next-oldest (a).
+    const entries = [entry('a:x', 100), entry('b:y', 10), entry('c:z', 300, true)];
+    expect(selectLruEvictionTargets(entries, 2)).toEqual(['a:x']);
+  });
+
+  it('can transiently exceed the cap when too many are busy', () => {
+    // cap 1, but both old entries busy → only the single idle one is evictable.
+    const entries = [entry('a:x', 100, true), entry('c:z', 300, true), entry('b:y', 10)];
+    expect(selectLruEvictionTargets(entries, 1)).toEqual(['b:y']);
+  });
+
+  it('uses the default cap when omitted', () => {
+    const entries = Array.from({ length: DEFAULT_MAX_LIVE_BACKENDS + 1 }, (_, i) =>
+      entry(`k${String(i).padStart(2, '0')}:a`, (i + 1) * 1000),
+    );
+    const evicted = selectLruEvictionTargets(entries);
+    // exactly one over the default cap → evict the single LRU (largest age).
+    expect(evicted).toHaveLength(1);
+    expect(evicted[0]).toBe(`k${String(DEFAULT_MAX_LIVE_BACKENDS).padStart(2, '0')}:a`);
+  });
+});
+
+describe('decideRestart (3.2, busy-aware)', () => {
+  const base = {
+    consecutiveFailures: 0,
+    busy: false,
+    unhealthyBusySince: 0,
+    now: NOW,
+    failureThreshold: 3,
+    staleBusyGraceMs: 120_000,
+  };
+
+  it('does nothing when healthy', () => {
+    expect(decideRestart({ ...base, processExited: false, healthy: true }))
+      .toEqual({ action: 'none', reason: 'healthy' });
+  });
+
+  it('restarts immediately when the process exited', () => {
+    expect(decideRestart({ ...base, processExited: true, busy: true }))
+      .toEqual({ action: 'restart', reason: 'process-exited' });
+  });
+
+  it('waits below the failure threshold', () => {
+    expect(decideRestart({ ...base, processExited: false, consecutiveFailures: 2 }))
+      .toEqual({ action: 'wait', reason: 'below-threshold' });
+  });
+
+  it('restarts at the threshold when idle', () => {
+    expect(decideRestart({ ...base, processExited: false, consecutiveFailures: 3 }))
+      .toEqual({ action: 'restart', reason: 'threshold' });
+  });
+
+  it('defers a restart while busy within the grace window', () => {
+    expect(decideRestart({
+      ...base, processExited: false, consecutiveFailures: 5, busy: true,
+      unhealthyBusySince: NOW - 1_000,
+    })).toEqual({ action: 'wait', reason: 'busy-grace' });
+  });
+
+  it('force-restarts a busy backend after the stale-busy grace', () => {
+    expect(decideRestart({
+      ...base, processExited: false, consecutiveFailures: 5, busy: true,
+      unhealthyBusySince: NOW - 120_001,
+    })).toEqual({ action: 'restart', reason: 'stale-busy-grace' });
+  });
+
+  it('waits (busy-grace) when busy + threshold but the window just started', () => {
+    // unhealthyBusySince === 0 means the caller is about to stamp it this cycle.
+    expect(decideRestart({
+      ...base, processExited: false, consecutiveFailures: 5, busy: true,
+      unhealthyBusySince: 0,
+    })).toEqual({ action: 'wait', reason: 'busy-grace' });
+  });
+});
+
+describe('selectOrphanWorktreeTargets (3.4)', () => {
+  it('skips dirs tracked by a live worktrees row', () => {
+    const onDisk = [{ path: '/wt/sess-a', mtimeMs: NOW - 10_000_000 }];
+    expect(selectOrphanWorktreeTargets(onDisk, new Set(['/wt/sess-a']), NOW, 1000)).toEqual([]);
+  });
+
+  it('reaps an untracked dir older than the grace', () => {
+    const onDisk = [{ path: '/wt/sess-orphan', mtimeMs: NOW - 5000 }];
+    expect(selectOrphanWorktreeTargets(onDisk, new Set(), NOW, 1000)).toEqual(['/wt/sess-orphan']);
+  });
+
+  it('never reaps a dir younger than the grace (mid-create race)', () => {
+    const onDisk = [{ path: '/wt/sess-fresh', mtimeMs: NOW - 500 }];
+    expect(selectOrphanWorktreeTargets(onDisk, new Set(), NOW, 1000)).toEqual([]);
+  });
+
+  it('mixes tracked, fresh, and orphaned correctly', () => {
+    const onDisk = [
+      { path: '/wt/sess-live', mtimeMs: NOW - 10_000 },
+      { path: '/wt/sess-fresh', mtimeMs: NOW - 100 },
+      { path: '/wt/sess-orphan', mtimeMs: NOW - 10_000 },
+    ];
+    expect(selectOrphanWorktreeTargets(onDisk, new Set(['/wt/sess-live']), NOW, 1000))
+      .toEqual(['/wt/sess-orphan']);
+  });
+});

apps/coder/src/services/backends/__tests__/opencode-concurrency.test.ts

@@ -0,0 +1,173 @@
+import { describe, it, expect, vi } from 'vitest';
+import type { Event, OpencodeClient } from '@opencode-ai/sdk/v2/client';
+import {
+  reconnectDecision,
+  runSessionEventLoop,
+  DEFAULT_RECONNECT_POLICY,
+  type SessionState,
+  type SseLoopDeps,
+} from '../opencode-sse.js';
+import { shouldStartServer } from '../opencode-server-process.js';
+
+/**
+ * v2.7 concurrency hardening (Phase 7): the pure decision cores for SSE reconnect
+ * backoff + the ensureServer double-spawn guard, plus a deterministic exercise of
+ * the loop's breaker (injected sleep, fake client). Happy path is asserted to be
+ * unchanged (clean stream end → reset → base-delay reconnect).
+ */
+
+function freshState(): SessionState {
+  return {
+    boocodeSessionId: 'boo1',
+    agentSessionId: 'oc1',
+    worktreePath: '/wt',
+    streamedPartKeys: new Set(),
+    partTypeById: new Map(),
+    activeTurn: { onEvent: () => {}, settle: () => {} },
+    watchdog: null,
+    sseAbort: null,
+    swallowNextTerminal: false,
+  };
+}
+
+const silentLog = {
+  warn: () => {},
+  info: () => {},
+  error: () => {},
+  debug: () => {},
+} as unknown as SseLoopDeps['log'];
+
+describe('reconnectDecision (pure backoff + breaker)', () => {
+  it('first failure uses the base delay (matches pre-hardening flat delay)', () => {
+    expect(reconnectDecision(1)).toEqual({ action: 'reconnect', delayMs: DEFAULT_RECONNECT_POLICY.baseMs });
+  });
+
+  it('grows exponentially and caps at maxMs', () => {
+    const policy = { baseMs: 1000, maxMs: 30_000, maxAttempts: 10 };
+    expect(reconnectDecision(2, policy)).toEqual({ action: 'reconnect', delayMs: 2000 });
+    expect(reconnectDecision(3, policy)).toEqual({ action: 'reconnect', delayMs: 4000 });
+    expect(reconnectDecision(6, policy)).toEqual({ action: 'reconnect', delayMs: 30_000 }); // 32000 capped
+    expect(reconnectDecision(9, policy)).toEqual({ action: 'reconnect', delayMs: 30_000 });
+  });
+
+  it('gives up once failures exceed maxAttempts', () => {
+    const policy = { baseMs: 1, maxMs: 8, maxAttempts: 3 };
+    expect(reconnectDecision(3, policy).action).toBe('reconnect');
+    expect(reconnectDecision(4, policy)).toEqual({ action: 'give-up' });
+  });
+});
+
+describe('shouldStartServer (double-spawn guard)', () => {
+  it('does not start when the server is live', () => {
+    expect(shouldStartServer({ up: true, hasClient: true, serverStarting: true, childDead: false, startInFlight: false })).toBe(false);
+  });
+
+  it('starts on a fresh process (no start in flight)', () => {
+    expect(shouldStartServer({ up: false, hasClient: false, serverStarting: false, childDead: false, startInFlight: false })).toBe(true);
+  });
+
+  it('re-spawns after a crash once the prior start finished', () => {
+    expect(shouldStartServer({ up: false, hasClient: false, serverStarting: true, childDead: true, startInFlight: false })).toBe(true);
+  });
+
+  it('does NOT double-spawn while a start is already in flight (the race fix)', () => {
+    expect(shouldStartServer({ up: false, hasClient: false, serverStarting: true, childDead: true, startInFlight: true })).toBe(false);
+  });
+
+  it('does NOT double-spawn when a crash nulled serverStarting mid-start', () => {
+    // The narrow window: a crash during the in-flight start (await freePort) nulls
+    // serverStarting while startInFlight is still true. The startInFlight guard must
+    // win over the !serverStarting branch, else a second server spawns on a new port.
+    expect(shouldStartServer({ up: false, hasClient: false, serverStarting: false, childDead: true, startInFlight: true })).toBe(false);
+  });
+
+  it('waits (no spawn) when a cached start exists and the child is still alive', () => {
+    expect(shouldStartServer({ up: false, hasClient: false, serverStarting: true, childDead: false, startInFlight: false })).toBe(false);
+  });
+});
+
+describe('runSessionEventLoop — happy path (unchanged)', () => {
+  it('dispatches streamed events, reconciles on clean end, reconnects at base delay', async () => {
+    const state = freshState();
+    const abort = new AbortController();
+    const events = [
+      { type: 'session.next.text.delta', properties: { sessionID: 'oc1', delta: 'hi' } },
+      { type: 'session.idle', properties: { sessionID: 'oc1' } },
+    ] as unknown as Event[];
+
+    const client = {
+      event: {
+        subscribe: vi.fn(async () => ({
+          stream: (async function* () {
+            for (const ev of events) yield ev;
+          })(),
+        })),
+      },
+    } as unknown as OpencodeClient;
+
+    const dispatched: Event[] = [];
+    const sleeps: number[] = [];
+    let reconciles = 0;
+
+    const deps: SseLoopDeps = {
+      isUp: () => true,
+      getClient: () => client,
+      dispatchEvent: (ev) => dispatched.push(ev),
+      reconcile: async () => {
+        reconciles += 1;
+        abort.abort(); // stop the loop after the first clean cycle
+        return false;
+      },
+      onReconnectGiveUp: () => {
+        throw new Error('should not give up on the happy path');
+      },
+      log: silentLog,
+      sleep: async (ms) => {
+        sleeps.push(ms);
+      },
+    };
+
+    await runSessionEventLoop(state, abort, deps);
+
+    expect(dispatched).toHaveLength(2);
+    expect(reconciles).toBe(1);
+    expect(sleeps).toEqual([DEFAULT_RECONNECT_POLICY.baseMs]); // base delay, not backed off
+  });
+});
+
+describe('runSessionEventLoop — circuit breaker', () => {
+  it('backs off on repeated throws then gives up + fails the turn', async () => {
+    const state = freshState();
+    const abort = new AbortController();
+    const policy = { baseMs: 1, maxMs: 8, maxAttempts: 3 };
+
+    const subscribe = vi.fn(async () => {
+      throw new Error('connection refused');
+    });
+    const client = { event: { subscribe } } as unknown as OpencodeClient;
+
+    const sleeps: number[] = [];
+    const gaveUp = vi.fn();
+
+    const deps: SseLoopDeps = {
+      isUp: () => true,
+      getClient: () => client,
+      dispatchEvent: () => {},
+      reconcile: async () => false,
+      onReconnectGiveUp: gaveUp,
+      log: silentLog,
+      sleep: async (ms) => {
+        sleeps.push(ms);
+      },
+      policy,
+    };
+
+    await runSessionEventLoop(state, abort, deps);
+
+    // 3 backoff sleeps (1, 2, 4), then the 4th failure trips the breaker.
+    expect(sleeps).toEqual([1, 2, 4]);
+    expect(subscribe).toHaveBeenCalledTimes(4);
+    expect(gaveUp).toHaveBeenCalledTimes(1);
+    expect(gaveUp).toHaveBeenCalledWith(state);
+  });
+});

apps/coder/src/services/backends/__tests__/opencode-event-map.test.ts

@@ -0,0 +1,226 @@
+import { describe, it, expect } from 'vitest';
+import type { Event, Part } from '@opencode-ai/sdk/v2/client';
+import {
+  stripDcpTags,
+  eventSessionId,
+  resolvePartDedupeKey,
+  mapToolStatus,
+  toolPartToSnapshot,
+  toolCalledSnapshot,
+  toolSuccessSnapshot,
+  toolFailedSnapshot,
+  classifyPartDelta,
+  classifyUpdatedPart,
+  errToString,
+  errMsg,
+  type DedupState,
+} from '../opencode-event-map.js';
+
+/**
+ * Pure opencode Event → AgentEvent translation + dedup gate (v2.7 audit reshape).
+ * Mirrors the original `dispatchEvent` / `handleUpdatedPart` arms verbatim — no
+ * I/O, so it's unit-testable. The slimmed backend keeps the routing + side effects.
+ */
+
+function freshDedup(): DedupState {
+  return { streamedPartKeys: new Set(), partTypeById: new Map() };
+}
+
+describe('stripDcpTags', () => {
+  it('removes a complete dcp tag', () => {
+    expect(stripDcpTags('hi <dcp-message-id>m1</dcp-message-id> there')).toBe('hi  there');
+  });
+  it('leaves untagged text untouched', () => {
+    expect(stripDcpTags('plain text <div>')).toBe('plain text <div>');
+  });
+});
+
+describe('eventSessionId', () => {
+  it('reads properties.sessionID for a normal event', () => {
+    const ev = { type: 'session.idle', properties: { sessionID: 's1' } } as unknown as Event;
+    expect(eventSessionId(ev)).toBe('s1');
+  });
+  it('reads properties.part.sessionID for message.part.updated', () => {
+    const ev = {
+      type: 'message.part.updated',
+      properties: { part: { sessionID: 's2' } },
+    } as unknown as Event;
+    expect(eventSessionId(ev)).toBe('s2');
+  });
+  it('returns null when there is no session', () => {
+    const ev = { type: 'server.connected', properties: {} } as unknown as Event;
+    expect(eventSessionId(ev)).toBeNull();
+  });
+});
+
+describe('resolvePartDedupeKey', () => {
+  it('prefers the part id', () => {
+    expect(resolvePartDedupeKey({ id: 'p1', messageID: 'm1' }, 'text')).toBe('text:p1');
+  });
+  it('falls back to the message id', () => {
+    expect(resolvePartDedupeKey({ id: '  ', messageID: 'm1' }, 'reasoning')).toBe('reasoning:message:m1');
+  });
+  it('returns null when neither is present', () => {
+    expect(resolvePartDedupeKey({ id: '', messageID: '' }, 'text')).toBeNull();
+  });
+});
+
+describe('mapToolStatus', () => {
+  it('maps the opencode tool states to ACP statuses', () => {
+    expect(mapToolStatus('pending')).toBe('pending');
+    expect(mapToolStatus('running')).toBe('in_progress');
+    expect(mapToolStatus('completed')).toBe('completed');
+    expect(mapToolStatus('error')).toBe('failed');
+    expect(mapToolStatus(undefined)).toBeNull();
+  });
+});
+
+describe('session.next.tool.* snapshot builders', () => {
+  it('toolCalledSnapshot → in_progress with tool title + raw input', () => {
+    expect(toolCalledSnapshot({ callID: 'c1', tool: 'read_file', input: { path: 'a.ts' } })).toEqual({
+      toolCallId: 'c1',
+      title: 'read_file',
+      kind: null,
+      status: 'in_progress',
+      rawInput: { path: 'a.ts' },
+      rawOutput: undefined,
+    });
+  });
+  it('toolSuccessSnapshot → completed with joined text content', () => {
+    const snap = toolSuccessSnapshot({ callID: 'c1', content: [{ text: 'foo' }, { text: 'bar' }, { other: 1 }] });
+    expect(snap.status).toBe('completed');
+    expect(snap.title).toBe('c1');
+    expect(snap.rawOutput).toBe('foobar');
+  });
+  it('toolSuccessSnapshot → empty output when content is missing', () => {
+    expect(toolSuccessSnapshot({ callID: 'c1' }).rawOutput).toBe('');
+  });
+  it('toolFailedSnapshot → failed with stringified error', () => {
+    const snap = toolFailedSnapshot({ callID: 'c1', error: 'boom' });
+    expect(snap.status).toBe('failed');
+    expect(snap.title).toBe('c1');
+    expect(snap.rawOutput).toBe('boom');
+  });
+});
+
+describe('toolPartToSnapshot', () => {
+  it('extracts input/output/title/status from the tool state', () => {
+    const part = {
+      type: 'tool',
+      callID: 'c1',
+      tool: 'grep',
+      state: { status: 'completed', input: { q: 'x' }, output: 'result', title: 'Grep run' },
+    } as unknown as Parameters<typeof toolPartToSnapshot>[0];
+    expect(toolPartToSnapshot(part)).toEqual({
+      toolCallId: 'c1',
+      title: 'Grep run',
+      kind: null,
+      status: 'completed',
+      rawInput: { q: 'x' },
+      rawOutput: 'result',
+    });
+  });
+  it('falls back to the tool name and uses error as output', () => {
+    const part = {
+      type: 'tool',
+      callID: 'c2',
+      tool: 'edit',
+      state: { status: 'error', error: 'nope' },
+    } as unknown as Parameters<typeof toolPartToSnapshot>[0];
+    const snap = toolPartToSnapshot(part);
+    expect(snap.title).toBe('edit');
+    expect(snap.status).toBe('failed');
+    expect(snap.rawOutput).toBe('nope');
+  });
+});
+
+describe('classifyPartDelta (message.part.delta dedup recording)', () => {
+  it('records a reasoning key and emits a reasoning event', () => {
+    const st = freshDedup();
+    const e = classifyPartDelta({ partID: 'p1', field: 'reasoning', delta: 'thinking' }, st);
+    expect(e).toEqual({ type: 'reasoning', text: 'thinking' });
+    expect(st.streamedPartKeys.has('reasoning:p1')).toBe(true);
+  });
+  it('records a text key, strips dcp, and emits text', () => {
+    const st = freshDedup();
+    const e = classifyPartDelta({ partID: 'p2', field: 'text', delta: 'hi <dcp-message-id>m</dcp-message-id>' }, st);
+    expect(e).toEqual({ type: 'text', text: 'hi ' });
+    expect(st.streamedPartKeys.has('text:p2')).toBe(true);
+  });
+  it('still records the text key even when the cleaned delta is empty', () => {
+    const st = freshDedup();
+    const e = classifyPartDelta({ partID: 'p3', field: 'text', delta: '<dcp-message-id>m</dcp-message-id>' }, st);
+    expect(e).toBeNull();
+    expect(st.streamedPartKeys.has('text:p3')).toBe(true);
+  });
+  it('uses the recorded part type when the field is absent', () => {
+    const st = freshDedup();
+    st.partTypeById.set('p4', 'reasoning');
+    const e = classifyPartDelta({ partID: 'p4', delta: 'more' }, st);
+    expect(e).toEqual({ type: 'reasoning', text: 'more' });
+  });
+  it('returns null for an unknown field', () => {
+    expect(classifyPartDelta({ partID: 'p5', field: 'other', delta: 'x' }, freshDedup())).toBeNull();
+  });
+});
+
+describe('classifyUpdatedPart (message.part.updated dedup gate)', () => {
+  function textPart(over: Partial<Part> = {}): Part {
+    return {
+      type: 'text',
+      id: 'p1',
+      messageID: 'm1',
+      sessionID: 's1',
+      text: 'final text',
+      time: { start: 1, end: 2 },
+      ...over,
+    } as unknown as Part;
+  }
+
+  it('drops a terminal part already streamed via deltas', () => {
+    const st = freshDedup();
+    st.streamedPartKeys.add('text:p1');
+    expect(classifyUpdatedPart(textPart(), st)).toBeNull();
+    // the key is consumed
+    expect(st.streamedPartKeys.has('text:p1')).toBe(false);
+  });
+  it('emits a finished (ended) text part not seen via deltas', () => {
+    const st = freshDedup();
+    expect(classifyUpdatedPart(textPart(), st)).toEqual({ type: 'text', text: 'final text' });
+    expect(st.partTypeById.get('p1')).toBe('text');
+  });
+  it('does not emit a part that has not ended yet', () => {
+    const st = freshDedup();
+    expect(classifyUpdatedPart(textPart({ time: { start: 1 } as never }), st)).toBeNull();
+  });
+  it('strips dcp tags from the finished text', () => {
+    const st = freshDedup();
+    const part = textPart({ text: 'a <dcp-message-id>m</dcp-message-id>b' });
+    expect(classifyUpdatedPart(part, st)).toEqual({ type: 'text', text: 'a b' });
+  });
+  it('maps a running tool part to tool_call', () => {
+    const st = freshDedup();
+    const part = { type: 'tool', callID: 'c1', tool: 'grep', state: { status: 'running' } } as unknown as Part;
+    const e = classifyUpdatedPart(part, st);
+    expect(e?.type).toBe('tool_call');
+  });
+  it('maps a completed tool part to tool_update', () => {
+    const st = freshDedup();
+    const part = { type: 'tool', callID: 'c1', tool: 'grep', state: { status: 'completed', output: 'x' } } as unknown as Part;
+    const e = classifyUpdatedPart(part, st);
+    expect(e?.type).toBe('tool_update');
+  });
+});
+
+describe('error formatters', () => {
+  it('errMsg unwraps Error.message', () => {
+    expect(errMsg(new Error('x'))).toBe('x');
+    expect(errMsg('plain')).toBe('plain');
+  });
+  it('errToString handles null/string/Error/object', () => {
+    expect(errToString(null)).toBe('unknown error');
+    expect(errToString('s')).toBe('s');
+    expect(errToString(new Error('e'))).toBe('e');
+    expect(errToString({ a: 1 })).toBe('{"a":1}');
+  });
+});

apps/coder/src/services/backends/__tests__/opencode-usage.test.ts

@@ -0,0 +1,51 @@
+import { describe, it, expect } from 'vitest';
+import { stepEndedToUsage } from '../opencode-usage.js';
+
+describe('stepEndedToUsage (U.6)', () => {
+  it('folds cache read+write into input and reasoning into output', () => {
+    const u = stepEndedToUsage({
+      cost: 0.0123,
+      tokens: { input: 100, output: 50, reasoning: 20, cache: { read: 10, write: 5 } },
+    });
+    expect(u).toEqual({ input: 115, output: 70, cost: 0.0123 });
+  });
+
+  it('handles a step with no cache and no reasoning', () => {
+    const u = stepEndedToUsage({
+      cost: 0,
+      tokens: { input: 8, output: 4, reasoning: 0, cache: { read: 0, write: 0 } },
+    });
+    expect(u).toEqual({ input: 8, output: 4, cost: 0 });
+  });
+
+  it('is defensive against a missing tokens block', () => {
+    const u = stepEndedToUsage({ cost: 0.5 } as never);
+    expect(u).toEqual({ input: 0, output: 0, cost: 0.5 });
+  });
+
+  it('is defensive against undefined props', () => {
+    expect(stepEndedToUsage(undefined)).toEqual({ input: 0, output: 0, cost: 0 });
+  });
+
+  it('drops NaN / negative noise to zero rather than poisoning the accumulated total', () => {
+    const u = stepEndedToUsage({
+      cost: Number.NaN,
+      tokens: {
+        input: -5,
+        output: Number.NaN,
+        reasoning: 3,
+        cache: { read: Number.POSITIVE_INFINITY, write: 2 },
+      },
+    });
+    // input: (-5→0) + (Inf→0) + 2 = 2; output: (NaN→0) + 3 = 3; cost: NaN→0
+    expect(u).toEqual({ input: 2, output: 3, cost: 0 });
+  });
+
+  it('rounds fractional token counts', () => {
+    const u = stepEndedToUsage({
+      cost: 1.5,
+      tokens: { input: 10.6, output: 4.4, reasoning: 0, cache: { read: 0, write: 0 } },
+    });
+    expect(u).toEqual({ input: 11, output: 4, cost: 1.5 });
+  });
+});

apps/coder/src/services/backends/__tests__/pushable-iterable.test.ts

@@ -0,0 +1,96 @@
+import { describe, it, expect } from 'vitest';
+import { createPushable } from '../pushable-iterable.js';
+
+/**
+ * The pushable async-iterable that feeds the Claude SDK's streaming-input query()
+ * one message per turn while staying open across turns. Tests cover the ordering
+ * contract (push/close/async-iterate) without any SDK shape.
+ */
+describe('createPushable — push/iterate ordering', () => {
+  it('yields buffered values in FIFO order then parks', async () => {
+    const p = createPushable<number>();
+    const it = p.iterable[Symbol.asyncIterator]();
+
+    p.push(1);
+    p.push(2);
+    expect(await it.next()).toEqual({ value: 1, done: false });
+    expect(await it.next()).toEqual({ value: 2, done: false });
+
+    // No more buffered → next() parks; resolve it by pushing.
+    const parked = it.next();
+    p.push(3);
+    expect(await parked).toEqual({ value: 3, done: false });
+  });
+
+  it('hands a value directly to a parked consumer (push after await)', async () => {
+    const p = createPushable<string>();
+    const it = p.iterable[Symbol.asyncIterator]();
+    const pending = it.next(); // parks immediately (empty buffer)
+    p.push('hello');
+    expect(await pending).toEqual({ value: 'hello', done: false });
+  });
+
+  it('close() resolves a parked consumer as done and reports done thereafter', async () => {
+    const p = createPushable<number>();
+    const it = p.iterable[Symbol.asyncIterator]();
+    const pending = it.next();
+    p.close();
+    expect(await pending).toEqual({ value: undefined, done: true });
+    expect(await it.next()).toEqual({ value: undefined, done: true });
+    expect(p.closed).toBe(true);
+  });
+
+  it('still drains values buffered BEFORE close', async () => {
+    const p = createPushable<number>();
+    const it = p.iterable[Symbol.asyncIterator]();
+    p.push(10);
+    p.push(20);
+    p.close();
+    expect(await it.next()).toEqual({ value: 10, done: false });
+    expect(await it.next()).toEqual({ value: 20, done: false });
+    expect(await it.next()).toEqual({ value: undefined, done: true });
+  });
+
+  it('drops values pushed after close', async () => {
+    const p = createPushable<number>();
+    const it = p.iterable[Symbol.asyncIterator]();
+    p.close();
+    p.push(99); // no-op
+    expect(await it.next()).toEqual({ value: undefined, done: true });
+  });
+
+  it('close() is idempotent', () => {
+    const p = createPushable<number>();
+    p.close();
+    expect(() => p.close()).not.toThrow();
+    expect(p.closed).toBe(true);
+  });
+
+  it('works with a for-await loop driven by interleaved pushes', async () => {
+    const p = createPushable<number>();
+    const seen: number[] = [];
+    const consumer = (async () => {
+      for await (const v of p.iterable) seen.push(v);
+    })();
+
+    p.push(1);
+    await Promise.resolve();
+    p.push(2);
+    await Promise.resolve();
+    p.close();
+    await consumer;
+    expect(seen).toEqual([1, 2]);
+  });
+
+  it('return() on the iterator closes the queue (for-await break)', async () => {
+    const p = createPushable<number>();
+    const it = p.iterable[Symbol.asyncIterator]();
+    p.push(1);
+    expect(await it.next()).toEqual({ value: 1, done: false });
+    // Simulate a `break` in for-await: the runtime calls return().
+    expect(await it.return!()).toEqual({ value: undefined, done: true });
+    expect(p.closed).toBe(true);
+    p.push(2); // dropped — queue is closed
+    expect(await it.next()).toEqual({ value: undefined, done: true });
+  });
+});

apps/coder/src/services/backends/__tests__/turn-guard.test.ts

@@ -0,0 +1,34 @@
+import { describe, it, expect } from 'vitest';
+import {
+  armAbortGuard,
+  noteTurnActivity,
+  consumeTerminal,
+  type AbortTerminalGuard,
+} from '../turn-guard.js';
+
+describe('post-abort terminal guard (F.1)', () => {
+  it('swallows the orphan terminal that follows an abort, then settles the next real one', () => {
+    // Reproduces the v2.6.5 Stop-button bug: abort turn A, then opencode emits a
+    // trailing session.idle for A. That orphan must NOT settle the next turn.
+    const g: AbortTerminalGuard = { swallowNextTerminal: false };
+
+    armAbortGuard(g); // user aborts turn A
+    expect(consumeTerminal(g)).toBe('swallow'); // opencode's orphan idle for A → dropped
+    expect(consumeTerminal(g)).toBe('settle'); // turn B's real idle → settles B
+  });
+
+  it('settles a terminal when no abort happened', () => {
+    const g: AbortTerminalGuard = { swallowNextTerminal: false };
+    expect(consumeTerminal(g)).toBe('settle');
+  });
+
+  it('self-heals if the orphan never arrives: new-turn activity clears the guard', () => {
+    // If opencode emits no orphan idle (e.g. abort-before-prompt), the next turn's
+    // real terminal must still settle rather than being swallowed forever.
+    const g: AbortTerminalGuard = { swallowNextTerminal: false };
+
+    armAbortGuard(g); // abort A, but no orphan idle arrives
+    noteTurnActivity(g); // turn B produces its first delta
+    expect(consumeTerminal(g)).toBe('settle'); // turn B's idle settles, not swallowed
+  });
+});

apps/coder/src/services/backends/__tests__/warm-acp-routing.test.ts

@@ -0,0 +1,59 @@
+import { describe, it, expect } from 'vitest';
+import { shouldUseWarmBackend, isTurnOkForStopReason } from '../warm-acp-routing.js';
+
+/**
+ * Phase 2 routing predicate: which goose/qwen tasks go to the warm pool backend
+ * vs the existing one-shot ACP path.
+ *
+ * The warm backend is keyed (chat_id, agent) — the persistent context unit (same
+ * as opencode-server). A task only routes warm when it carries BOTH a session_id
+ * and a chat_id, i.e. it originates from a real chat tab (the coder message route
+ * stamps both). Session-less creators (arena, MCP-created, generic /api/tasks,
+ * new_task) lack chat_id/session_id and keep the one-shot worktree-per-task path,
+ * which never spawns a warm process.
+ */
+describe('shouldUseWarmBackend (Phase 2 routing)', () => {
+  it('routes a chat-tab task (session_id + chat_id) to the warm backend', () => {
+    expect(shouldUseWarmBackend({ agent: 'qwen', session_id: 's1', chat_id: 'c1' })).toBe(true);
+    expect(shouldUseWarmBackend({ agent: 'goose', session_id: 's1', chat_id: 'c1' })).toBe(true);
+  });
+
+  it('keeps a session-less arena/MCP task on the one-shot path', () => {
+    expect(shouldUseWarmBackend({ agent: 'qwen', session_id: null, chat_id: null })).toBe(false);
+  });
+
+  it('keeps a task with a session but no chat on the one-shot path', () => {
+    // chat_id is the warm-key half; without it ensureSession would get a degenerate
+    // (null, agent) key, so fall back to one-shot rather than synthesize a chat.
+    expect(shouldUseWarmBackend({ agent: 'goose', session_id: 's1', chat_id: null })).toBe(false);
+  });
+
+  it('keeps a task with a chat but no session on the one-shot path', () => {
+    expect(shouldUseWarmBackend({ agent: 'qwen', session_id: null, chat_id: 'c1' })).toBe(false);
+  });
+
+  it('only applies to warm-capable agents (goose, qwen); others never warm here', () => {
+    // opencode has its own dedicated warm path; native/claude/etc. are not ACP-warm.
+    expect(shouldUseWarmBackend({ agent: 'opencode', session_id: 's1', chat_id: 'c1' })).toBe(false);
+    expect(shouldUseWarmBackend({ agent: 'claude', session_id: 's1', chat_id: 'c1' })).toBe(false);
+    expect(shouldUseWarmBackend({ agent: null, session_id: 's1', chat_id: 'c1' })).toBe(false);
+  });
+});
+
+describe('isTurnOkForStopReason (ACP stop-reason → ok/fail)', () => {
+  it('treats normal completions as ok', () => {
+    expect(isTurnOkForStopReason('end_turn')).toBe(true);
+    expect(isTurnOkForStopReason('max_tokens')).toBe(true);
+    expect(isTurnOkForStopReason('max_turn_requests')).toBe(true);
+  });
+
+  it('treats refusal and cancelled as failures', () => {
+    expect(isTurnOkForStopReason('refusal')).toBe(false);
+    expect(isTurnOkForStopReason('cancelled')).toBe(false);
+  });
+
+  it('defaults an absent stop reason to a successful end_turn', () => {
+    expect(isTurnOkForStopReason(undefined)).toBe(true);
+    expect(isTurnOkForStopReason(null)).toBe(true);
+  });
+});

apps/coder/src/services/backends/claude-sdk-map.ts

@@ -0,0 +1,245 @@
+/**
+ * claude-sdk-sessionstore #9 (Part 2) — PURE Claude-SDK message → AgentEvent mapper.
+ *
+ * `ClaudeSdkBackend` drives one `query()` per (chat, agent) session and feeds each
+ * `SDKMessage` it yields through this function, forwarding the returned
+ * `AgentEvent[]` to the dispatcher's `onEvent` (which maps them to WS frames +
+ * persists). Kept PURE (one message + a caller-owned accumulator → events) so it's
+ * unit-testable without a live `claude` binary — the whole point of Part 2's
+ * typecheck-and-unit-test gate (the live pump needs a host smoke).
+ *
+ * SDK shapes (verified against @anthropic-ai/claude-agent-sdk@0.3.159 sdk.d.ts +
+ * @anthropic-ai/sdk beta messages d.ts):
+ *   - `SDKPartialAssistantMessage` (`type:'stream_event'`) carries a
+ *     `BetaRawMessageStreamEvent` — the LIVE delta stream (only emitted when
+ *     `options.includePartialMessages` is set, which the backend sets). We map:
+ *       · content_block_delta + text_delta      → { text }
+ *       · content_block_delta + thinking_delta   → { reasoning }
+ *       · content_block_start  + tool_use block  → { tool_call } (in_progress)
+ *       · content_block_delta + input_json_delta → buffered into the tool's args
+ *         (no event; the assembled input rides the terminal tool_update)
+ *   - `SDKAssistantMessage` (`type:'assistant'`) carries the FINAL `message.content`
+ *     blocks. Text/thinking there are post-hoc repeats of what the partials already
+ *     streamed, so we DROP them (dedup) and only emit a terminal `tool_update`
+ *     (status completed) per `tool_use` block, with its now-complete `input`.
+ *   - All other `SDKMessage` variants (system/init, status, result, hooks, task
+ *     notifications, …) carry no renderable turn content → return [].
+ *
+ * Tool assembly spans messages: a tool_use block opens in a partial
+ * `content_block_start`, its args stream as `input_json_delta` frames keyed by the
+ * block `index`, and the final assistant message restates the complete block. The
+ * caller owns a `ClaudeSdkMapState` (snapshot map + per-index tool tracking) that
+ * threads this across calls, mirroring the `Map<string, AcpToolSnapshot>` the other
+ * backends pass into `mapSessionUpdate`. The result frames carry the SAME
+ * `AcpToolSnapshot` shape, so `persistExternalAgentTurn` / `snapshotToWireToolCall`
+ * are reused unchanged.
+ */
+import type { SDKMessage } from '@anthropic-ai/claude-agent-sdk';
+import type { AgentEvent } from '../agent-backend.js';
+import type { AcpToolSnapshot } from '../acp-tool-snapshot.js';
+
+/**
+ * The underlying `@anthropic-ai/sdk` Beta message types (`BetaRawMessageStreamEvent`,
+ * `BetaContentBlock`) are a TRANSITIVE dep of `@anthropic-ai/claude-agent-sdk` — not
+ * a direct dependency of apps/coder — so a `@anthropic-ai/sdk/...` import does NOT
+ * resolve here under pnpm's strict node_modules. We instead DERIVE both shapes from
+ * the SDK's own exported message types, which is also more correct (it tracks the
+ * exact `event` / `content` shapes the SDK yields, not a hand-picked import path).
+ */
+type StreamEvent = Extract<SDKMessage, { type: 'stream_event' }>['event'];
+type AssistantContent = Extract<SDKMessage, { type: 'assistant' }>['message']['content'];
+type ContentBlock = AssistantContent extends readonly (infer B)[] ? B : never;
+type UserContent = Extract<SDKMessage, { type: 'user' }>['message']['content'];
+
+/**
+ * Caller-owned accumulator threaded across `mapSdkMessage` calls within ONE turn.
+ * The backend creates a fresh one per turn and clears it at turn end.
+ */
+export interface ClaudeSdkMapState {
+  /** Stable tool-call snapshots by tool_use id, merged across start/delta/stop. */
+  snapshots: Map<string, AcpToolSnapshot>;
+  /**
+   * Partial-stream block index → in-flight tool assembly. Anthropic's stream keys
+   * blocks by a numeric `index`; tool_use args arrive as `input_json_delta`s under
+   * that index with no id, so we map index→id to route them and buffer the raw
+   * JSON fragments until the block closes (or the final assistant message lands).
+   */
+  toolByIndex: Map<number, { id: string; name: string; jsonBuf: string }>;
+}
+
+/** Construct a fresh per-turn accumulator. */
+export function createClaudeSdkMapState(): ClaudeSdkMapState {
+  return { snapshots: new Map(), toolByIndex: new Map() };
+}
+
+/**
+ * Map one `SDKMessage` → zero or more `AgentEvent`s, mutating `state` for
+ * cross-message tool assembly + dedup. Pure w.r.t. its inputs otherwise.
+ */
+export function mapSdkMessage(msg: SDKMessage, state: ClaudeSdkMapState): AgentEvent[] {
+  switch (msg.type) {
+    case 'stream_event':
+      return mapStreamEvent(msg.event, state);
+    case 'assistant':
+      return mapFinalAssistant(msg.message.content, state);
+    case 'user':
+      // Tool RESULTS ride in as user messages (tool_result blocks): the SDK ran
+      // the tool and feeds its output back. Without mapping these, the tool_call
+      // never reaches a terminal snapshot — it persists as status:'running' with
+      // no output and the UI spinner never stops (the bug this fixes).
+      return mapUserToolResults(msg.message.content, state);
+    default:
+      // system/init, status, result, hooks, task_*, etc. — no turn content here.
+      // (The backend reads session_id off the init message and usage/cost off the
+      // result message directly; neither produces a renderable AgentEvent.)
+      return [];
+  }
+}
+
+/** Live partial-stream delta → AgentEvent(s). */
+function mapStreamEvent(event: StreamEvent, state: ClaudeSdkMapState): AgentEvent[] {
+  switch (event.type) {
+    case 'content_block_start': {
+      const block = event.content_block;
+      if (block.type === 'tool_use') {
+        const snap: AcpToolSnapshot = {
+          toolCallId: block.id,
+          title: block.name,
+          kind: null,
+          status: 'in_progress',
+          rawInput: block.input ?? undefined,
+          rawOutput: undefined,
+        };
+        state.snapshots.set(block.id, snap);
+        state.toolByIndex.set(event.index, { id: block.id, name: block.name, jsonBuf: '' });
+        return [{ type: 'tool_call', toolCall: snap }];
+      }
+      return [];
+    }
+    case 'content_block_delta': {
+      const delta = event.delta;
+      if (delta.type === 'text_delta') {
+        return delta.text ? [{ type: 'text', text: delta.text }] : [];
+      }
+      if (delta.type === 'thinking_delta') {
+        return delta.thinking ? [{ type: 'reasoning', text: delta.thinking }] : [];
+      }
+      if (delta.type === 'input_json_delta') {
+        // Buffer the tool's streamed args under its block index; no event yet —
+        // the assembled input rides the terminal tool_update (or the final block).
+        const t = state.toolByIndex.get(event.index);
+        if (t) t.jsonBuf += delta.partial_json ?? '';
+        return [];
+      }
+      // signature_delta / citations_delta / compaction_delta — nothing to render.
+      return [];
+    }
+    case 'content_block_stop': {
+      // Close out a streamed tool block: parse its buffered JSON args and emit a
+      // tool_update carrying the assembled input. The final assistant message will
+      // restate the same block, but its snapshot is dedup-merged (same id) so this
+      // is harmless — we emit here so a tool's input renders even if the assistant
+      // message is delayed/dropped.
+      const t = state.toolByIndex.get(event.index);
+      if (!t) return [];
+      state.toolByIndex.delete(event.index);
+      const prev = state.snapshots.get(t.id);
+      const snap: AcpToolSnapshot = {
+        toolCallId: t.id,
+        title: prev?.title ?? t.name,
+        kind: null,
+        status: 'in_progress',
+        rawInput: parseJsonOr(t.jsonBuf, prev?.rawInput),
+        rawOutput: undefined,
+      };
+      state.snapshots.set(t.id, snap);
+      return [{ type: 'tool_update', toolCall: snap }];
+    }
+    default:
+      // message_start / message_delta / message_stop — turn framing, no content.
+      return [];
+  }
+}
+
+/**
+ * Final assistant message content blocks. Text/thinking are post-hoc repeats of
+ * the partial stream → dropped (dedup). Only tool_use blocks emit a terminal
+ * tool_update carrying the complete `input`.
+ */
+function mapFinalAssistant(content: ContentBlock[], state: ClaudeSdkMapState): AgentEvent[] {
+  const out: AgentEvent[] = [];
+  for (const block of content) {
+    if (block.type === 'tool_use') {
+      const prev = state.snapshots.get(block.id);
+      const snap: AcpToolSnapshot = {
+        toolCallId: block.id,
+        title: prev?.title ?? block.name,
+        kind: null,
+        status: 'completed',
+        rawInput: block.input ?? prev?.rawInput,
+        rawOutput: undefined,
+      };
+      state.snapshots.set(block.id, snap);
+      out.push({ type: 'tool_update', toolCall: snap });
+    }
+    // text / thinking / redacted_thinking blocks: already streamed via partials.
+  }
+  return out;
+}
+
+/**
+ * User-message tool_result blocks → terminal tool_update events. The SDK runs
+ * each tool and feeds the output back in a `user` message; we mark the matching
+ * snapshot completed (or failed, on is_error) WITH its output so the snapshot
+ * persists/renders as resolved instead of spinning. Unknown ids (no prior
+ * snapshot) are still surfaced so a stray result isn't silently lost.
+ */
+function mapUserToolResults(content: UserContent, state: ClaudeSdkMapState): AgentEvent[] {
+  if (!Array.isArray(content)) return [];
+  const out: AgentEvent[] = [];
+  for (const raw of content) {
+    const block = raw as { type?: string; tool_use_id?: string; content?: unknown; is_error?: boolean };
+    if (block.type !== 'tool_result' || !block.tool_use_id) continue;
+    const prev = state.snapshots.get(block.tool_use_id);
+    const snap: AcpToolSnapshot = {
+      toolCallId: block.tool_use_id,
+      title: prev?.title ?? block.tool_use_id,
+      kind: prev?.kind ?? null,
+      status: block.is_error ? 'failed' : 'completed',
+      rawInput: prev?.rawInput,
+      rawOutput: toolResultText(block.content),
+    };
+    state.snapshots.set(block.tool_use_id, snap);
+    out.push({ type: 'tool_update', toolCall: snap });
+  }
+  return out;
+}
+
+/** tool_result content is a string OR an array of content blocks (text/image).
+ *  Flatten text blocks; fall back to the raw value so nothing is lost. */
+function toolResultText(content: unknown): unknown {
+  if (typeof content === 'string') return content;
+  if (Array.isArray(content)) {
+    const text = content
+      .map((c) =>
+        c && typeof c === 'object' && (c as { type?: string }).type === 'text'
+          ? String((c as { text?: unknown }).text ?? '')
+          : '',
+      )
+      .filter(Boolean)
+      .join('\n');
+    return text || content;
+  }
+  return content ?? '';
+}
+
+/** Parse a buffered JSON string; fall back to a prior value on empty/invalid. */
+function parseJsonOr(buf: string, fallback: unknown): unknown {
+  const s = buf.trim();
+  if (!s) return fallback;
+  try {
+    return JSON.parse(s);
+  } catch {
+    return fallback;
+  }
+}

apps/coder/src/services/backends/claude-sdk-routing.ts

@@ -0,0 +1,38 @@
+/**
+ * claude-sdk-sessionstore #9 (Part 2) — claude-SDK-vs-PTY routing predicate.
+ *
+ * Sibling to `shouldUseWarmBackend` (warm-acp-routing.ts). The warm Claude-SDK
+ * backend keys its persistent `query()` on (chat_id, agent) — exactly like the
+ * warm-ACP / opencode-server backends — so a task only routes to it when it carries
+ * BOTH a `session_id` and a `chat_id` (a real chat tab).
+ *
+ * CRUCIALLY this is ALSO gated behind the `CLAUDE_SDK_BACKEND` env flag (default
+ * OFF). While off — the production default — claude always falls through to the
+ * existing one-shot PTY `runExternalAgent` path, UNCHANGED. The live SDK streaming
+ * pump + cross-turn resume need a host smoke against the real `claude` binary, so
+ * we keep the working PTY path as the default until that lands. Flip the env var
+ * on a host (any truthy value) to opt a deployment into the SDK backend.
+ *
+ * Pure (env read injected) so it's unit-testable; the dispatcher consumes it.
+ */
+
+/** True iff the `CLAUDE_SDK_BACKEND` env flag is set to a truthy value. */
+export function claudeSdkBackendEnabled(env: NodeJS.ProcessEnv = process.env): boolean {
+  const v = env.CLAUDE_SDK_BACKEND;
+  if (v == null) return false;
+  const s = v.trim().toLowerCase();
+  return s !== '' && s !== '0' && s !== 'false' && s !== 'off' && s !== 'no';
+}
+
+export function shouldUseClaudeSdk(
+  task: {
+    agent: string | null;
+    session_id: string | null;
+    chat_id: string | null;
+  },
+  env: NodeJS.ProcessEnv = process.env,
+): boolean {
+  if (!claudeSdkBackendEnabled(env)) return false;
+  if (task.agent !== 'claude') return false;
+  return task.session_id != null && task.chat_id != null;
+}

apps/coder/src/services/backends/claude-sdk.ts

@@ -0,0 +1,425 @@
+/**
+ * claude-sdk-sessionstore #9 (Part 2) — ClaudeSdkBackend.
+ *
+ * A warm, resumable backend for the `claude` agent built on the Claude Agent SDK
+ * (`@anthropic-ai/claude-agent-sdk`), implementing the Phase-0 `AgentBackend`
+ * contract (same shape as `WarmAcpBackend` / `OpenCodeServerBackend`). One
+ * persistent `query()` per (chat, agent) session, driven in STREAMING-INPUT mode:
+ * the `prompt` is a pushable `AsyncIterable<SDKUserMessage>` that stays open across
+ * turns, so the SDK subprocess + conversation stay warm between `prompt()` calls
+ * until `closeSession`/`dispose`.
+ *
+ * ⚠ LIVE PUMP IS HOST-ONLY. The actual streaming turn needs the real `claude`
+ * binary + ANTHROPIC auth on a host — it CANNOT run in the dev container. This file
+ * is written against the REAL SDK types so it TYPECHECKS, and the PURE pieces (the
+ * `mapSdkMessage` mapper + the `createPushable` queue) are unit-tested. Routing to
+ * this backend is gated behind `CLAUDE_SDK_BACKEND` (default OFF) so production
+ * claude stays on the working PTY path until a host smoke validates the pump +
+ * cross-turn resume.
+ *
+ * Lifecycle (mirrors warm-acp.ts / opencode-server.ts):
+ *   - `ensureSession`: resolve the resume id from `agent_sessions(chat_id,'claude')`
+ *     and (re)build the single `query()` if not already live. The SDK's own
+ *     `sessionStore` (Part 1 PostgresSessionStore) materializes the transcript on
+ *     resume; `options.resume` carries the provider session id.
+ *   - `prompt`: push ONE user message onto the open queue, iterate the generator,
+ *     map each `SDKMessage` → `AgentEvent`s via `mapSdkMessage`, forward to
+ *     `ctx.onEvent`, and resolve when the turn's `result` message lands. Capture the
+ *     `session_id` from the `init` message and persist it to `agent_sessions`;
+ *     accumulate `result.usage` / `total_cost_usd` onto the row (mirrors opencode U.6).
+ *   - `closeSession` / `dispose`: close the queue + dispose the query generator.
+ *   - A thrown error or `result.subtype==='error*'` marks `agent_sessions.status='crashed'`.
+ *
+ * Turn serialization: like warm-acp, exactly one turn is in flight at a time on a
+ * given backend (the dispatcher's per-session `inflight` map enforces this upstream;
+ * `isBusy()` reports it so the pool never evicts mid-turn).
+ */
+import { query, type Query, type SDKMessage, type SDKUserMessage, type Options } from '@anthropic-ai/claude-agent-sdk';
+import type { FastifyBaseLogger } from 'fastify';
+import type { Sql } from '../../db.js';
+import { PostgresSessionStore } from './claude-session-store.js';
+import { createPushable, type Pushable } from './pushable-iterable.js';
+import { mapSdkMessage, createClaudeSdkMapState, type ClaudeSdkMapState } from './claude-sdk-map.js';
+import type {
+  AgentBackend,
+  AgentSessionHandle,
+  EnsureSessionOpts,
+  PromptCtx,
+  TurnResult,
+} from '../agent-backend.js';
+
+export interface ClaudeSdkBackendDeps {
+  sql: Sql;
+  log: FastifyBaseLogger;
+  /** The (chat, agent) this backend serves — its pool identity + DB key. */
+  chatId: string;
+  /** Always 'claude' today; kept explicit so the pool key + DB writes stay honest. */
+  agent: string;
+  /** Resolved `claude` binary path (available_agents.install_path); null → SDK default. */
+  installPath: string | null;
+}
+
+export class ClaudeSdkBackend implements AgentBackend {
+  readonly backend = 'claude_sdk' as const;
+
+  private readonly sql: Sql;
+  private readonly log: FastifyBaseLogger;
+  private readonly chatId: string;
+  private readonly agent: string;
+  private readonly installPath: string | null;
+  private readonly sessionStore: PostgresSessionStore;
+
+  /** The single persistent query() generator; null until the first turn builds it. */
+  private query: Query | null = null;
+  /** The open input queue feeding the generator one SDKUserMessage per turn. */
+  private input: Pushable<SDKUserMessage> | null = null;
+  /** The provider's own session id (resume token), captured from the init message. */
+  private agentSessionId: string | null = null;
+  /** Resolved model the live query() was built with; a change forces a rebuild. */
+  private builtModel: string | null = null;
+  /** True between prompt() start and settle. */
+  private busy = false;
+  private up = false;
+
+  constructor(deps: ClaudeSdkBackendDeps) {
+    this.sql = deps.sql;
+    this.log = deps.log;
+    this.chatId = deps.chatId;
+    this.agent = deps.agent;
+    this.installPath = deps.installPath;
+    this.sessionStore = new PostgresSessionStore(deps.sql);
+  }
+
+  /** §2: liveness for the health endpoint + dispatcher fallback decision. */
+  health(): 'up' | 'down' {
+    return this.up ? 'up' : 'down';
+  }
+
+  /** Phase 3: busy iff a turn is in flight (pool never evicts a busy backend). */
+  isBusy(): boolean {
+    return this.busy;
+  }
+
+  // ─── ensureSession: resolve resume id + (re)build the warm query ──────────────
+
+  async ensureSession(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle> {
+    // Resolve the resume token from the (chat_id, agent) row. A crashed row is not
+    // resumed (the SDK would fail to load a dead session); we create fresh.
+    const [row] = await this.sql<{ agent_session_id: string | null; status: string }[]>`
+      SELECT agent_session_id, status FROM agent_sessions
+      WHERE chat_id = ${opts.chatId} AND agent = ${opts.agent}
+    `;
+    const resumeId = row && row.status !== 'crashed' ? row.agent_session_id : null;
+
+    // (Re)build the warm query if there is none, or the model changed (the SDK can
+    // change model mid-session via setModel, but a fresh build is simplest + matches
+    // opencode's config-drift → fresh-session rule). The query stays alive across
+    // turns; only closeSession/dispose tears it down.
+    if (!this.query || this.builtModel !== opts.model) {
+      await this.teardownQuery();
+      this.buildQuery(opts.worktreePath, opts.model, resumeId);
+    }
+
+    // Seed the in-memory resume id from the DB so a handle built before the first
+    // turn's init message still carries the last-known token. The init message
+    // overwrites it with the authoritative current id during the turn.
+    if (this.agentSessionId == null) this.agentSessionId = resumeId;
+
+    // Upsert the agent_sessions row (backend='claude_sdk'). agent_session_id may be
+    // null until the first turn captures it from the init message; prompt() updates it.
+    await this.sql`
+      INSERT INTO agent_sessions
+        (chat_id, session_id, worktree_id, agent, backend, agent_session_id, server_port, status, last_active_at)
+      VALUES
+        (${opts.chatId}, ${sessionId}, ${opts.worktreeId}, ${opts.agent}, 'claude_sdk', ${this.agentSessionId}, NULL, 'active', clock_timestamp())
+      ON CONFLICT (chat_id, agent) DO UPDATE SET
+        session_id = EXCLUDED.session_id,
+        worktree_id = EXCLUDED.worktree_id,
+        backend = 'claude_sdk',
+        agent_session_id = COALESCE(EXCLUDED.agent_session_id, agent_sessions.agent_session_id),
+        server_port = NULL,
+        status = 'active',
+        last_active_at = clock_timestamp()
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: opts.chatId, agent: opts.agent }, 'claude-sdk: agent_sessions upsert failed (non-fatal)');
+    });
+
+    return {
+      sessionId,
+      agent: opts.agent,
+      backend: 'claude_sdk',
+      chatId: opts.chatId,
+      worktreeId: opts.worktreeId,
+      agentSessionId: this.agentSessionId,
+      serverPort: null,
+    };
+  }
+
+  /** Build the persistent query() in streaming-input mode. Lazy — no subprocess
+   *  work happens until the generator is first iterated in prompt(). */
+  private buildQuery(worktreePath: string, model: string, resumeId: string | null): void {
+    const input = createPushable<SDKUserMessage>();
+    const options: Options = {
+      sessionStore: this.sessionStore,
+      cwd: worktreePath,
+      // Stream partial assistant messages so text/thinking/tool deltas arrive live
+      // (the mapper reads them; without this only terminal messages land).
+      includePartialMessages: true,
+      // BooCode default: enable the documented 1M-context-window beta. Active on
+      // models that support it (the SDK lists Sonnet 4/4.5); a non-supporting model
+      // simply doesn't get the larger window. The TRUE window is read back from
+      // `result.modelUsage[*].contextWindow` and shown in the ContextBar, so whatever
+      // window a model actually gets is surfaced truthfully (no guessing).
+      betas: ['context-1m-2025-08-07'],
+      ...(model ? { model } : {}),
+      ...(resumeId ? { resume: resumeId } : {}),
+      ...(this.installPath ? { pathToClaudeCodeExecutable: this.installPath } : {}),
+      // ANTHROPIC auth/env must reach the child; inherit the process env (host concern).
+      env: process.env as Record<string, string>,
+    };
+    this.input = input;
+    this.query = query({ prompt: input.iterable, options });
+    this.builtModel = model;
+    this.up = true;
+    this.log.info({ chatId: this.chatId, agent: this.agent, model, resume: resumeId ?? null }, 'claude-sdk: warm query built');
+  }
+
+  // ─── prompt: push one user message + drain the generator until result ─────────
+
+  async prompt(handle: AgentSessionHandle, input: string, ctx: PromptCtx): Promise<TurnResult> {
+    if (!this.query || !this.input) {
+      // ensureSession should have built it; rebuild defensively (e.g. evicted/raced).
+      this.buildQuery(ctx.worktreePath, ctx.model, handle.agentSessionId);
+    }
+    const gen = this.query!;
+    const queue = this.input!;
+
+    if (ctx.signal.aborted) return { ok: false, error: 'aborted' };
+
+    this.busy = true;
+    const state: ClaudeSdkMapState = createClaudeSdkMapState();
+    // Peak per-request input (incl. cache) across the turn ≈ the conversation context
+    // held in the window. result.usage SUMS input over the turn's internal requests
+    // (overcounts for multi-tool turns), so the per-request peak is the accurate
+    // "context used" for the ContextBar (paseo's approach).
+    let maxInputTokens = 0;
+    // Per-turn abort: interrupt the in-flight query on the SAME generator (never
+    // tear down the warm query — that's the pool's lifetime). The generator then
+    // emits its terminal result and the drain loop exits.
+    let aborted = false;
+    const onAbort = () => {
+      if (aborted) return;
+      aborted = true;
+      void gen.interrupt().catch(() => {});
+    };
+    ctx.signal.addEventListener('abort', onAbort, { once: true });
+
+    // Push the turn's user message onto the open queue. session_id is optional on
+    // the wire; the SDK manages it via resume + the init message.
+    const userMsg: SDKUserMessage = {
+      type: 'user',
+      message: { role: 'user', content: input },
+      parent_tool_use_id: null,
+      ...(handle.agentSessionId ? { session_id: handle.agentSessionId } : {}),
+    };
+    queue.push(userMsg);
+
+    try {
+      // Manual iteration — NOT `for await (… of gen)`. Returning out of a for-await
+      // loop calls gen.return(), which CLOSES the async generator; that killed the
+      // warm streaming-input query after a single turn, so every FOLLOW-UP message
+      // hit a dead generator and failed. gen.next() leaves the generator suspended
+      // (alive) for the next pushed user message — the warm query is only closed
+      // deliberately in teardownQuery()/dispose().
+      while (true) {
+        const next = await gen.next();
+        if (next.done) {
+          // Generator ended (e.g. disposed) without a result — non-fatal incomplete.
+          if (aborted) return { ok: false, error: 'aborted' };
+          return { ok: false, error: 'claude-sdk: query ended before result' };
+        }
+        const msg = next.value;
+        // Track the peak per-request input from message_start usage (delivered by
+        // includePartialMessages) — the largest single request's input is the real
+        // context fill, unlike the summed result.usage.
+        if (msg.type === 'stream_event') {
+          const sev = msg.event as { type?: string; message?: { usage?: Record<string, unknown> } };
+          if (sev?.type === 'message_start' && sev.message?.usage) {
+            const ru = sev.message.usage;
+            const reqInput =
+              num(ru.input_tokens) + num(ru.cache_read_input_tokens) + num(ru.cache_creation_input_tokens);
+            if (reqInput > maxInputTokens) maxInputTokens = reqInput;
+          }
+        }
+        // Capture the provider session id from the init message (authoritative).
+        if (msg.type === 'system' && msg.subtype === 'init' && msg.session_id) {
+          if (this.agentSessionId !== msg.session_id) {
+            this.agentSessionId = msg.session_id;
+            await this.persistAgentSessionId(msg.session_id);
+          }
+        }
+        // The result message ends THIS turn (it does not close the generator —
+        // streaming-input keeps it alive for the next pushed message).
+        if (msg.type === 'result') {
+          await this.accumulateUsage(msg);
+          const ok = msg.subtype === 'success' && !aborted;
+          if (!ok) {
+            // error_during_execution / error_max_turns / aborted → crashed row.
+            await this.markCrashed();
+          } else {
+            await this.markIdle();
+          }
+          if (aborted) return { ok: false, error: 'aborted' };
+          if (!ok) return { ok: false, error: resultErrorMessage(msg) };
+          // Context-window telemetry for the ContextBar (paseo's method):
+          //   ctxMax = the model's OWN reported window (1M-aware — reflects the active
+          //            window, so the bar shows the truth per model);
+          //   ctxUsed = peak request input (history in the window) + this turn's output.
+          const ctxMax = extractMaxContextWindow((msg as { modelUsage?: unknown }).modelUsage);
+          const fallbackInput =
+            num(msg.usage?.input_tokens) +
+            num(msg.usage?.cache_read_input_tokens) +
+            num(msg.usage?.cache_creation_input_tokens);
+          const ctxUsed = (maxInputTokens || fallbackInput) + num(msg.usage?.output_tokens);
+          return {
+            ok: true,
+            ...(ctxMax > 0 ? { ctxMax } : {}),
+            ...(ctxUsed > 0 ? { ctxUsed } : {}),
+          };
+        }
+        // Map renderable content → AgentEvents for the dispatcher's onEvent.
+        for (const ev of mapSdkMessage(msg, state)) {
+          ctx.onEvent(ev);
+        }
+      }
+    } catch (err) {
+      if (aborted) return { ok: false, error: 'aborted' };
+      await this.markCrashed();
+      return { ok: false, error: errMsg(err) };
+    } finally {
+      ctx.signal.removeEventListener('abort', onAbort);
+      this.busy = false;
+    }
+  }
+
+  // ─── persistence helpers ──────────────────────────────────────────────────────
+
+  private async persistAgentSessionId(id: string): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions
+      SET agent_session_id = ${id}, last_active_at = clock_timestamp()
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: this.chatId }, 'claude-sdk: failed to persist agent_session_id (non-fatal)');
+    });
+  }
+
+  /**
+   * Accumulate the turn's usage/cost onto the (chat_id, agent) row — mirrors the
+   * opencode U.6 running-total pattern. The SDK reports usage once per turn on the
+   * result message (not per step), so this fires once per prompt(). Cache read/write
+   * input tokens fold into `input_tokens`; usage telemetry never fails a turn.
+   */
+  private async accumulateUsage(result: Extract<SDKMessage, { type: 'result' }>): Promise<void> {
+    const u = result.usage;
+    const input = num(u?.input_tokens) + num(u?.cache_read_input_tokens) + num(u?.cache_creation_input_tokens);
+    const output = num(u?.output_tokens);
+    const cost = numF(result.total_cost_usd);
+    if (input === 0 && output === 0 && cost === 0) return;
+    await this.sql`
+      UPDATE agent_sessions SET
+        input_tokens = input_tokens + ${input},
+        output_tokens = output_tokens + ${output},
+        cost = cost + ${cost}
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: this.chatId }, 'claude-sdk: failed to persist usage (non-fatal)');
+    });
+  }
+
+  private async markIdle(): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions SET status = 'idle', last_active_at = clock_timestamp()
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch(() => {});
+  }
+
+  private async markCrashed(): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions SET status = 'crashed'
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch(() => {});
+  }
+
+  // ─── teardown ────────────────────────────────────────────────────────────────
+
+  async closeSession(handle: AgentSessionHandle): Promise<void> {
+    await this.teardownQuery();
+    await this.sql`
+      UPDATE agent_sessions SET status = 'closed'
+      WHERE chat_id = ${handle.chatId} AND agent = ${handle.agent}
+    `.catch(() => {});
+  }
+
+  async dispose(): Promise<void> {
+    await this.teardownQuery();
+  }
+
+  /** Close the input queue + dispose the generator. Idempotent. */
+  private async teardownQuery(): Promise<void> {
+    this.up = false;
+    this.busy = false;
+    const q = this.query;
+    const queue = this.input;
+    this.query = null;
+    this.input = null;
+    this.builtModel = null;
+    queue?.close();
+    if (q) {
+      // return() ends the AsyncGenerator and lets the SDK clean up its subprocess.
+      await q.return(undefined).catch(() => {});
+    }
+  }
+}
+
+// ─── helpers ──────────────────────────────────────────────────────────────────
+
+/** Coerce to a non-negative finite integer (tokens). */
+function num(v: unknown): number {
+  const x = typeof v === 'number' ? v : Number(v);
+  return Number.isFinite(x) && x > 0 ? Math.round(x) : 0;
+}
+
+/** Coerce to a non-negative finite float (cost USD). */
+function numF(v: unknown): number {
+  const x = typeof v === 'number' ? v : Number(v);
+  return Number.isFinite(x) && x > 0 ? x : 0;
+}
+
+/** Largest context-window the SDK reports across `result.modelUsage` (a
+ *  `Record<model, ModelUsage>`, each with a `contextWindow`). This is the model's
+ *  OWN window — 1M when the 1M model/beta is active, 200K otherwise — so the
+ *  ContextBar shows the true window without us mapping model→size ourselves. */
+function extractMaxContextWindow(modelUsage: unknown): number {
+  if (!modelUsage || typeof modelUsage !== 'object') return 0;
+  let max = 0;
+  for (const v of Object.values(modelUsage as Record<string, unknown>)) {
+    if (v && typeof v === 'object') {
+      const cw = (v as { contextWindow?: unknown }).contextWindow;
+      if (typeof cw === 'number' && Number.isFinite(cw) && cw > max) max = cw;
+    }
+  }
+  return max;
+}
+
+/** Build a human-readable error from an SDK error-result message. */
+function resultErrorMessage(result: Extract<SDKMessage, { type: 'result' }>): string {
+  if (result.subtype === 'success') return 'ok';
+  const errs = (result as { errors?: string[] }).errors;
+  if (Array.isArray(errs) && errs.length > 0) return `${result.subtype}: ${errs.join('; ')}`;
+  return result.subtype;
+}
+
+function errMsg(e: unknown): string {
+  return e instanceof Error ? e.message : String(e);
+}

apps/coder/src/services/backends/claude-session-store.ts

@@ -0,0 +1,117 @@
+import type { SessionStore, SessionKey, SessionStoreEntry } from '@anthropic-ai/claude-agent-sdk';
+import type { Sql } from '../../db.js';
+
+/**
+ * claude-sdk-sessionstore #9 (Part 1) — clean-room PostgresSessionStore.
+ *
+ * A Postgres-backed implementation of the Claude Agent SDK's `SessionStore`
+ * adapter type. The SDK mirrors each transcript line (a JSON-safe POJO with a
+ * `type` discriminant) to this store via `append`; on resume it calls `load`
+ * to materialize the full transcript back. We treat entries as opaque blobs and
+ * preserve append order via a BIGSERIAL `id` — `load` replays `ORDER BY id`.
+ *
+ * Storage shape: one row per entry in `claude_session_entries`, keyed by the
+ * SDK's `SessionKey` (project_key, session_id, subpath). The SDK uses an
+ * *undefined* subpath for the main transcript and disallows the empty string;
+ * we collapse `undefined → ''` so the main transcript and subagent files share
+ * one table, distinguished by the `subpath` column (`'' = main`).
+ *
+ * Clean-room: written against the SDK's published `SessionStore` type contract
+ * and BooCode's existing SQL conventions (porsager tagged templates, `sql.json`
+ * for JSONB). No SDK example/reference code was consulted.
+ */
+export class PostgresSessionStore implements SessionStore {
+  constructor(private readonly sql: Sql) {}
+
+  /**
+   * Mirror a batch of transcript entries. No-op on an empty batch; otherwise a
+   * single multi-row INSERT writes them in array order. Because `id` is a
+   * monotonically-increasing BIGSERIAL, the insert order is the replay order
+   * `load` reconstructs — entries within one call land in the order given.
+   */
+  async append(key: SessionKey, entries: SessionStoreEntry[]): Promise<void> {
+    if (entries.length === 0) return;
+    const subpath = key.subpath ?? '';
+    const rows = entries.map((entry) => ({
+      project_key: key.projectKey,
+      session_id: key.sessionId,
+      subpath,
+      entry: this.sql.json(entry as never),
+    }));
+    await this.sql`
+      INSERT INTO claude_session_entries ${this.sql(rows, 'project_key', 'session_id', 'subpath', 'entry')}
+    `;
+  }
+
+  /**
+   * Load a full transcript for resume. Returns the entries in append order, or
+   * `null` for a (project_key, session_id, subpath) key that was never written.
+   */
+  async load(key: SessionKey): Promise<SessionStoreEntry[] | null> {
+    const subpath = key.subpath ?? '';
+    const rows = await this.sql<{ entry: SessionStoreEntry }[]>`
+      SELECT entry
+      FROM claude_session_entries
+      WHERE project_key = ${key.projectKey}
+        AND session_id = ${key.sessionId}
+        AND subpath = ${subpath}
+      ORDER BY id
+    `;
+    if (rows.length === 0) return null;
+    return rows.map((r) => r.entry);
+  }
+
+  /**
+   * List the main transcripts for a project. `mtime` is the storage write time
+   * (latest `created_at` for the session) in Unix epoch milliseconds; the SDK
+   * sorts the result by mtime descending.
+   */
+  async listSessions(projectKey: string): Promise<Array<{ sessionId: string; mtime: number }>> {
+    const rows = await this.sql<{ session_id: string; mtime: string }[]>`
+      SELECT session_id, extract(epoch FROM max(created_at)) * 1000 AS mtime
+      FROM claude_session_entries
+      WHERE project_key = ${projectKey}
+        AND subpath = ''
+      GROUP BY session_id
+    `;
+    return rows.map((r) => ({ sessionId: r.session_id, mtime: Number(r.mtime) }));
+  }
+
+  /**
+   * Delete a session. With a `subpath` set, only that subpath's rows are
+   * removed; with `subpath` omitted, every row for the session is removed
+   * (all subpaths, including the main transcript).
+   */
+  async delete(key: SessionKey): Promise<void> {
+    if (key.subpath !== undefined) {
+      await this.sql`
+        DELETE FROM claude_session_entries
+        WHERE project_key = ${key.projectKey}
+          AND session_id = ${key.sessionId}
+          AND subpath = ${key.subpath}
+      `;
+      return;
+    }
+    await this.sql`
+      DELETE FROM claude_session_entries
+      WHERE project_key = ${key.projectKey}
+        AND session_id = ${key.sessionId}
+    `;
+  }
+
+  /**
+   * List the distinct non-main subpaths under a session (e.g. subagent files).
+   * Used during resume to discover and materialize subagent transcripts; the
+   * main transcript (`subpath = ''`) is excluded.
+   */
+  async listSubkeys(key: { projectKey: string; sessionId: string }): Promise<string[]> {
+    const rows = await this.sql<{ subpath: string }[]>`
+      SELECT DISTINCT subpath
+      FROM claude_session_entries
+      WHERE project_key = ${key.projectKey}
+        AND session_id = ${key.sessionId}
+        AND subpath <> ''
+    `;
+    return rows.map((r) => r.subpath);
+  }
+}

apps/coder/src/services/backends/lifecycle-decisions.ts

@@ -0,0 +1,197 @@
+/**
+ * v2.6 Phase 3 — pure lifecycle decision helpers.
+ *
+ * The eviction / LRU-cap / busy-aware-restart / reaper-target logic, factored out
+ * of AgentPool + the backends + the periodic sweeper so it's unit-testable with no
+ * DB, no child processes, no timers (modeled on
+ * apps/server/src/services/inference/prune.ts:selectPruneTargets — a pure decision
+ * core the caller acts on).
+ *
+ * Three decisions live here:
+ *   1. selectIdleEvictionTargets — which warm backends to evict for being idle.
+ *   2. selectLruEvictionTargets — which warm backends to evict to honour a max-live
+ *      cap (least-recently-used beyond the cap), NEVER a busy one.
+ *   3. shouldRestartCrashedBackend (busy-aware) — openchamber's skip-while-busy +
+ *      stale-grace state machine, re-implemented for BooCode's per-(chat,agent) pool.
+ *
+ * "Busy" = the backend has an in-flight turn. The hard rule (design §6, decisions):
+ * never evict or force-restart a busy backend; defer with a stale-grace.
+ */
+
+// ─── Idle TTL eviction (3.1) ─────────────────────────────────────────────────
+
+/** Default idle TTL before a warm backend/session is evicted (design §6 ~30 min). */
+export const DEFAULT_IDLE_TTL_MS = 30 * 60 * 1000;
+
+/** A pool entry as the decision helpers see it (no backend internals). */
+export interface PoolEntrySnapshot {
+  /** Pool key `${primary}:${agent}` — opaque to the decision, used for selection. */
+  key: string;
+  /** Epoch ms of the last turn activity (start or settle) on this backend. */
+  lastActiveAt: number;
+  /** True iff a turn is in flight right now. Busy entries are never evicted. */
+  busy: boolean;
+}
+
+/**
+ * Idle eviction: an entry is evictable when it has been idle (no turn) for longer
+ * than `ttlMs` AND is not currently busy. Returns the keys to evict.
+ *
+ * Pure: `now` is injected so tests don't depend on wall-clock. Busy entries are
+ * categorically excluded — a long-running turn that exceeds the TTL must NOT be
+ * torn down mid-stream (the §6 / openchamber busy rule).
+ */
+export function selectIdleEvictionTargets(
+  entries: ReadonlyArray<PoolEntrySnapshot>,
+  now: number,
+  ttlMs: number = DEFAULT_IDLE_TTL_MS,
+): string[] {
+  const out: string[] = [];
+  for (const e of entries) {
+    if (e.busy) continue;
+    if (now - e.lastActiveAt >= ttlMs) out.push(e.key);
+  }
+  return out;
+}
+
+// ─── LRU cap (3.4) ───────────────────────────────────────────────────────────
+
+/** Default max live warm backends/worktrees before the LRU cap evicts (env-overridable). */
+export const DEFAULT_MAX_LIVE_BACKENDS = 10;
+
+/**
+ * LRU cap: when more than `cap` non-busy entries are live, evict the
+ * least-recently-used ones (oldest `lastActiveAt` first) until at most `cap`
+ * remain. Busy entries are never evicted AND are not counted toward the cap's
+ * "kept" budget being freed — i.e. we only ever evict idle entries, so a burst of
+ * concurrent busy turns can transiently exceed the cap rather than kill live work.
+ *
+ * Returns the keys to evict, least-recently-used first. Pure / deterministic:
+ * ties broken by key for stable test output.
+ */
+export function selectLruEvictionTargets(
+  entries: ReadonlyArray<PoolEntrySnapshot>,
+  cap: number = DEFAULT_MAX_LIVE_BACKENDS,
+): string[] {
+  if (cap < 0) cap = 0;
+  if (entries.length <= cap) return [];
+  // Only idle entries are eligible to be evicted.
+  const evictable = entries
+    .filter((e) => !e.busy)
+    .sort((a, b) => a.lastActiveAt - b.lastActiveAt || (a.key < b.key ? -1 : a.key > b.key ? 1 : 0));
+  // We must shrink total live count down to `cap`. Busy entries can't be evicted,
+  // so the number we CAN remove is bounded by the evictable pool; evict the oldest
+  // (total - cap) of them, never more than exist.
+  const overBy = entries.length - cap;
+  const toEvict = evictable.slice(0, Math.max(0, overBy));
+  return toEvict.map((e) => e.key);
+}
+
+// ─── Busy-aware crash restart (3.2) — openchamber lift ───────────────────────
+
+/**
+ * Default grace after which a backend that has stayed unhealthy WHILE busy is
+ * force-restarted anyway (openchamber's STALE_BUSY_GRACE_MS = 2 min). Guards
+ * against a permanently-stuck "busy" turn wedging recovery forever.
+ */
+export const DEFAULT_STALE_BUSY_GRACE_MS = 2 * 60 * 1000;
+
+/** Default consecutive health-check failures before a restart is attempted. */
+export const DEFAULT_HEALTH_FAILURE_THRESHOLD = 3;
+
+export interface RestartDecisionInput {
+  /** True iff the process is actually dead (exited). A dead process restarts
+   *  immediately regardless of busy/threshold — there's nothing to protect. */
+  processExited: boolean;
+  /** Consecutive failed health probes so far (including the current one). */
+  consecutiveFailures: number;
+  /** Whether the backend currently has an in-flight turn. */
+  busy: boolean;
+  /** Epoch ms when the unhealthy-while-busy window started, or 0 if not in one. */
+  unhealthyBusySince: number;
+  /** Injected clock. */
+  now: number;
+  failureThreshold?: number;
+  staleBusyGraceMs?: number;
+}
+
+export type RestartDecision =
+  | { action: 'restart'; reason: 'process-exited' | 'threshold' | 'stale-busy-grace' }
+  | { action: 'wait'; reason: 'below-threshold' | 'busy-grace' }
+  | { action: 'none'; reason: 'healthy' };
+
+/**
+ * Decide whether to restart a backend after a health probe. Mirrors
+ * openchamber's `runHealthCheckCycle` + `shouldSkipRestartForBusySessions`,
+ * re-implemented as a pure function over injected state (the caller owns the
+ * mutable counters + the actual restart side-effect).
+ *
+ * Order (matches openchamber):
+ *   - process exited            → restart now (nothing live to protect).
+ *   - below failure threshold   → wait (transient blip; the next probe re-checks).
+ *   - threshold reached + idle   → restart now.
+ *   - threshold reached + busy   → skip UNLESS the unhealthy-busy window exceeded
+ *                                  the stale grace, then force restart.
+ *
+ * `healthy: true` callers don't reach here; included for completeness so the
+ * caller can pass through and reset counters on a single code path.
+ */
+export function decideRestart(input: RestartDecisionInput & { healthy?: boolean }): RestartDecision {
+  if (input.healthy) return { action: 'none', reason: 'healthy' };
+  if (input.processExited) return { action: 'restart', reason: 'process-exited' };
+
+  const threshold = input.failureThreshold ?? DEFAULT_HEALTH_FAILURE_THRESHOLD;
+  if (input.consecutiveFailures < threshold) {
+    return { action: 'wait', reason: 'below-threshold' };
+  }
+
+  if (!input.busy) {
+    return { action: 'restart', reason: 'threshold' };
+  }
+
+  // Busy + unhealthy at/over threshold: defer, but not forever.
+  const grace = input.staleBusyGraceMs ?? DEFAULT_STALE_BUSY_GRACE_MS;
+  if (input.unhealthyBusySince > 0 && input.now - input.unhealthyBusySince >= grace) {
+    return { action: 'restart', reason: 'stale-busy-grace' };
+  }
+  return { action: 'wait', reason: 'busy-grace' };
+}
+
+// ─── Orphan worktree reaper target selection (3.4) ───────────────────────────
+
+/** Default TTL: an on-disk worktree dir with no live `worktrees` row is reaped
+ *  only after it's been orphaned at least this long (mtime-based grace so a
+ *  just-created dir mid-`ensureSessionWorktree` race is never swept). */
+export const DEFAULT_ORPHAN_WORKTREE_GRACE_MS = 60 * 60 * 1000; // 1h
+
+export interface OnDiskWorktree {
+  /** Absolute path of the worktree dir on disk. */
+  path: string;
+  /** Last-modified epoch ms of the dir (newest of dir + contents, caller's choice). */
+  mtimeMs: number;
+}
+
+/**
+ * Reaper target selection: which on-disk worktree dirs are orphans safe to
+ * inspect-and-reap. An orphan is a dir under the worktree base that has NO live
+ * `worktrees` row (path not in `liveWorktreePaths`) AND whose mtime is older than
+ * the grace window (so an in-flight create isn't swept).
+ *
+ * Pure — the caller (the sweeper) then runs the at-risk preflight (dirty/unpushed)
+ * on each returned path and only physically removes the SAFE ones. This helper
+ * never decides to remove work-at-risk; it only narrows the candidate set.
+ */
+export function selectOrphanWorktreeTargets(
+  onDisk: ReadonlyArray<OnDiskWorktree>,
+  liveWorktreePaths: ReadonlySet<string>,
+  now: number,
+  graceMs: number = DEFAULT_ORPHAN_WORKTREE_GRACE_MS,
+): string[] {
+  const out: string[] = [];
+  for (const w of onDisk) {
+    if (liveWorktreePaths.has(w.path)) continue; // tracked → not an orphan
+    if (now - w.mtimeMs < graceMs) continue; // too fresh → could be mid-create
+    out.push(w.path);
+  }
+  return out;
+}

apps/coder/src/services/backends/opencode-event-map.ts

@@ -0,0 +1,203 @@
+/**
+ * Pure opencode `Event` → normalized `AgentEvent` translation.
+ *
+ * Extracted (v2.7 audit reshape) from `OpenCodeServerBackend.dispatchEvent` /
+ * `handleUpdatedPart` and the file-local helpers. NO I/O, no timers, no DB, no
+ * `byOpencodeId` — every function here is a deterministic transform over its
+ * arguments (the dedup state is caller-owned and mutated in place, mirroring the
+ * `acp-event-map.ts` `priorSnapshots` pattern). This is the unit-testable core; the
+ * backend keeps the routing + side effects (watchdog, usage persistence, settle).
+ *
+ * Depends only on SDK TYPES + AcpToolSnapshot — safe to import anywhere.
+ */
+import type { Event, Part, ToolPart, ToolState } from '@opencode-ai/sdk/v2/client';
+import type { ToolCallStatus } from '@agentclientprotocol/sdk';
+import type { AcpToolSnapshot } from '../acp-tool-snapshot.js';
+import type { AgentEvent } from '../agent-backend.js';
+
+/** Per-(opencode session) dedup state the part-stream classifiers read + mutate. */
+export interface DedupState {
+  /** dedup gate: `${type}:${id}` added on delta, deleted-and-tested on updated. */
+  streamedPartKeys: Set<string>;
+  /** partID → 'text' | 'reasoning', so a delta with a non-'reasoning' field is still classed right. */
+  partTypeById: Map<string, string>;
+}
+
+/** Strip opencode-dcp plugin tags that render as literal text in the UI. */
+export function stripDcpTags(s: string): string {
+  return s.replace(/<dcp-message-id>[^<]*<\/dcp-message-id>/g, '');
+}
+
+/** Extract the opencode sessionID an event belongs to, across event shapes.
+ *  Most carry `properties.sessionID`; `message.part.updated` nests it under
+ *  `properties.part.sessionID`. Returns null when the event has no session
+ *  (the per-session loop then leaves it to dispatchEvent, which drops it). */
+export function eventSessionId(ev: Event): string | null {
+  const props = (ev as { properties?: unknown }).properties;
+  if (!props || typeof props !== 'object') return null;
+  if (ev.type === 'message.part.updated') {
+    const part = (props as { part?: { sessionID?: string } }).part;
+    return part?.sessionID ?? null;
+  }
+  return (props as { sessionID?: string }).sessionID ?? null;
+}
+
+/** Ported verbatim from Paseo opencode-agent.ts: id → message-id fallback → null. */
+export function resolvePartDedupeKey(part: { id: string; messageID: string }, type: string): string | null {
+  if (part.id.trim().length > 0) return `${type}:${part.id}`;
+  if (part.messageID.trim().length > 0) return `${type}:message:${part.messageID}`;
+  return null;
+}
+
+export function mapToolStatus(s: ToolState['status'] | undefined): ToolCallStatus | null {
+  switch (s) {
+    case 'pending':
+      return 'pending';
+    case 'running':
+      return 'in_progress';
+    case 'completed':
+      return 'completed';
+    case 'error':
+      return 'failed';
+    default:
+      return null;
+  }
+}
+
+/** opencode ToolPart → ACP-shaped snapshot (reuses the existing persist/render path). */
+export function toolPartToSnapshot(part: ToolPart): AcpToolSnapshot {
+  const state = part.state;
+  let rawInput: unknown;
+  let rawOutput: unknown;
+  let title: string | undefined;
+  if (state) {
+    if ('input' in state) rawInput = (state as { input?: unknown }).input;
+    if ('output' in state) rawOutput = (state as { output?: unknown }).output;
+    else if ('error' in state) rawOutput = (state as { error?: unknown }).error;
+    if ('title' in state) title = (state as { title?: string }).title;
+  }
+  return {
+    toolCallId: part.callID,
+    title: title ?? part.tool,
+    kind: null,
+    status: mapToolStatus(state?.status),
+    rawInput,
+    rawOutput,
+  };
+}
+
+// ─── session.next.tool.* snapshot builders ───────────────────────────────────
+
+/** `session.next.tool.called` → an in-progress tool_call snapshot. */
+export function toolCalledSnapshot(p: { callID: string; tool: string; input: unknown }): AcpToolSnapshot {
+  return {
+    toolCallId: p.callID,
+    title: p.tool,
+    kind: null,
+    status: 'in_progress',
+    rawInput: p.input,
+    rawOutput: undefined,
+  };
+}
+
+/** `session.next.tool.success` → a completed tool snapshot (text content joined). */
+export function toolSuccessSnapshot(p: { callID: string; content?: ReadonlyArray<unknown> | null }): AcpToolSnapshot {
+  const output = p.content?.map((c) => (c && typeof c === 'object' && 'text' in c ? (c as { text: string }).text : '')).join('') ?? '';
+  return {
+    toolCallId: p.callID,
+    title: p.callID,
+    kind: null,
+    status: 'completed',
+    rawInput: undefined,
+    rawOutput: output,
+  };
+}
+
+/** `session.next.tool.failed` → a failed tool snapshot (error stringified). */
+export function toolFailedSnapshot(p: { callID: string; error: unknown }): AcpToolSnapshot {
+  return {
+    toolCallId: p.callID,
+    title: p.callID,
+    kind: null,
+    status: 'failed',
+    rawInput: undefined,
+    rawOutput: errToString(p.error),
+  };
+}
+
+// ─── message.part.* dedup gate ────────────────────────────────────────────────
+
+/**
+ * `message.part.delta`: mark the part as streamed (so a later `message.part.updated`
+ * for the same part is deduped) and return the AgentEvent to emit, or null when the
+ * field is neither reasoning nor text, or a text delta strips down to empty. Mutates
+ * `st.streamedPartKeys` exactly as the original inline arm did (the key is recorded
+ * for text even when the cleaned delta is empty).
+ */
+export function classifyPartDelta(
+  p: { partID: string; field?: string; delta: string },
+  st: DedupState,
+): AgentEvent | null {
+  const isReasoning = p.field === 'reasoning' || st.partTypeById.get(p.partID) === 'reasoning';
+  if (isReasoning) {
+    st.streamedPartKeys.add(`reasoning:${p.partID}`);
+    return { type: 'reasoning', text: p.delta };
+  }
+  if (p.field === 'text') {
+    st.streamedPartKeys.add(`text:${p.partID}`);
+    const cleaned = stripDcpTags(p.delta);
+    return cleaned ? { type: 'text', text: cleaned } : null;
+  }
+  return null;
+}
+
+/**
+ * `message.part.updated` terminal part: the dedup gate for text/reasoning (drop a
+ * part already streamed via deltas; otherwise emit the finished text) plus the
+ * tool-part → tool_call/tool_update mapping. Returns null when nothing should be
+ * emitted. Mutates `st.partTypeById` / `st.streamedPartKeys` like the original.
+ */
+export function classifyUpdatedPart(part: Part, st: DedupState): AgentEvent | null {
+  if (part.type === 'text' || part.type === 'reasoning') {
+    st.partTypeById.set(part.id, part.type);
+    const key = resolvePartDedupeKey(part, part.type);
+    if (key && st.streamedPartKeys.delete(key)) return null; // already streamed via delta
+    const raw = part.text ?? '';
+    const text = part.type === 'text' ? stripDcpTags(raw) : raw;
+    if (text && part.time?.end != null) {
+      return { type: part.type, text };
+    }
+    return null;
+  }
+
+  if (part.type === 'tool') {
+    const snap = toolPartToSnapshot(part);
+    const status = part.state?.status;
+    // tool_call on start (pending/running), tool_update on terminal (completed/error).
+    // The current ACP path merges both into one frame; the contract keeps them
+    // distinct because opencode's SSE distinguishes start from result.
+    return status === 'completed' || status === 'error'
+      ? { type: 'tool_update', toolCall: snap }
+      : { type: 'tool_call', toolCall: snap };
+  }
+  // NOTE: opencode's SSE payload union carries no available-commands event, so the
+  // AgentEvent 'commands' arm is intentionally never emitted here.
+  return null;
+}
+
+// ─── shared error formatters (pure) ───────────────────────────────────────────
+
+export function errMsg(e: unknown): string {
+  return e instanceof Error ? e.message : String(e);
+}
+
+export function errToString(e: unknown): string {
+  if (e == null) return 'unknown error';
+  if (typeof e === 'string') return e;
+  if (e instanceof Error) return e.message;
+  try {
+    return JSON.stringify(e);
+  } catch {
+    return String(e);
+  }
+}

apps/coder/src/services/backends/opencode-server-process.ts

@@ -0,0 +1,325 @@
+/**
+ * OpenCodeServerSupervisor — the opencode `serve` child + HTTP client + port +
+ * health-counter lifecycle, extracted (v2.7 audit reshape) from the backend
+ * god-class. Owns spawn / ready / crash / proactive-health restart / dispose and
+ * exposes `client` / `port` / `health()` / `tickHealth()` to the backend.
+ *
+ * Session-level recovery (failing in-flight turns, marking agent_sessions crashed,
+ * tearing down SSE loops) is NOT a process concern — it's delegated back to the
+ * backend through the injected `hooks.onServerDown` callback, keeping this module
+ * free of the demux map / SQL / turn state.
+ *
+ * v2.7 concurrency hardening: `ensureServer` is guarded against the crash-window
+ * double-spawn (two concurrent callers each re-spawning on different ports) via a
+ * synchronous `startInFlight` flag — see `shouldStartServer`.
+ */
+import { spawn, type ChildProcess } from 'node:child_process';
+import { createOpencodeClient, type OpencodeClient } from '@opencode-ai/sdk/v2/client';
+import type { FastifyBaseLogger } from 'fastify';
+import { decideRestart, DEFAULT_HEALTH_FAILURE_THRESHOLD } from './lifecycle-decisions.js';
+import { reclaimPort, waitForPortRelease, freePort } from '../net/port-utils.js';
+
+const READY_TIMEOUT_MS = 30_000;
+
+/** Info handed to the backend when the server goes down (crash or forced restart). */
+export interface ServerDownInfo {
+  code: number | null;
+  signal: NodeJS.Signals | null;
+  port: number;
+}
+
+export interface SupervisorHooks {
+  /** True iff ANY pooled session has an in-flight turn (defers a busy restart). */
+  isBusy: () => boolean;
+  /** Session-level recovery: fail in-flight turns, mark crashed, drop demux state. */
+  onServerDown: (info: ServerDownInfo) => void;
+}
+
+export interface OpenCodeServerSupervisorDeps {
+  /** Absolute path to the opencode binary (resolved from available_agents). */
+  opencodeBinary: string;
+  log: FastifyBaseLogger;
+  hooks: SupervisorHooks;
+}
+
+/**
+ * Pure decision for `ensureServer`: should we (re)spawn the server right now?
+ *
+ * - A live, ready server (`up && client`) → no.
+ * - A start already in flight (`startInFlight`) → no, NEVER double-spawn — join the
+ *   running start instead. This is checked BEFORE `serverStarting` because the crash
+ *   handler can null `serverStarting` mid-start (a crash during `await freePort()`),
+ *   and without this guard the `!serverStarting` branch would spawn a second server
+ *   on a different port while the first is still coming up.
+ * - No start cached/running → yes (fresh start or post-crash re-spawn, since the
+ *   crash handler nulls `serverStarting`).
+ * - A cached start that already finished, but the child has since died and the crash
+ *   handler hasn't reset us yet → yes.
+ */
+export function shouldStartServer(s: {
+  up: boolean;
+  hasClient: boolean;
+  serverStarting: boolean;
+  childDead: boolean;
+  startInFlight: boolean;
+}): boolean {
+  if (s.up && s.hasClient) return false;
+  if (s.startInFlight) return false;
+  if (!s.serverStarting) return true;
+  if (!s.up && s.childDead) return true;
+  return false;
+}
+
+export class OpenCodeServerSupervisor {
+  private readonly opencodeBinary: string;
+  private readonly log: FastifyBaseLogger;
+  private readonly hooks: SupervisorHooks;
+
+  private childProc: ChildProcess | null = null;
+  private opencodeClient: OpencodeClient | null = null;
+  private serverPort: number | null = null;
+  private up = false;
+  private serverStarting: Promise<void> | null = null;
+  /** True from the synchronous head of startServer() until it settles — the
+   *  double-spawn guard reads it so a concurrent ensureServer joins instead of
+   *  kicking a second spawn. */
+  private startInFlight = false;
+  // Phase 3 busy-aware health monitor (openchamber lift): consecutive failed
+  // probes + the start of an unhealthy-while-busy window feed `decideRestart`.
+  private consecutiveHealthFailures = 0;
+  private unhealthyBusySince = 0;
+  private restarting: Promise<void> | null = null;
+
+  constructor(deps: OpenCodeServerSupervisorDeps) {
+    this.opencodeBinary = deps.opencodeBinary;
+    this.log = deps.log;
+    this.hooks = deps.hooks;
+  }
+
+  /** The live opencode HTTP client, or null between (re)starts. */
+  get client(): OpencodeClient | null {
+    return this.opencodeClient;
+  }
+
+  /** The current server port, or null before the first start. */
+  get port(): number | null {
+    return this.serverPort;
+  }
+
+  /** §2: liveness for the health endpoint + dispatcher fallback decision. */
+  health(): 'up' | 'down' {
+    return this.up ? 'up' : 'down';
+  }
+
+  isUp(): boolean {
+    return this.up;
+  }
+
+  // ─── lifecycle (spawn once + client + ready; crash-restart) ──────────────────
+
+  /**
+   * Lazy: start the single server on first use; re-spawn after a crash. Idempotent
+   * within one live server — `serverStarting` caches the in-flight start, reset to
+   * null by the crash handler so the NEXT ensureServer re-spawns. A dead-but-not-
+   * yet-reaped child (exit handler raced) is also treated as needing a restart.
+   * Concurrent callers in a crash window are coalesced via `startInFlight`.
+   */
+  ensureServer(): Promise<void> {
+    if (this.up && this.opencodeClient) return Promise.resolve();
+    const childDead =
+      this.childProc != null && (this.childProc.exitCode !== null || this.childProc.signalCode !== null);
+    if (
+      shouldStartServer({
+        up: this.up,
+        hasClient: this.opencodeClient != null,
+        serverStarting: this.serverStarting != null,
+        childDead,
+        startInFlight: this.startInFlight,
+      })
+    ) {
+      this.serverStarting = this.startServer();
+    }
+    return this.serverStarting ?? Promise.resolve();
+  }
+
+  private async startServer(): Promise<void> {
+    // Set synchronously (before the first await) so a concurrent ensureServer sees
+    // the in-flight start and joins `serverStarting` instead of double-spawning.
+    this.startInFlight = true;
+    try {
+      const port = await freePort();
+
+      // Phase 1: run unsecured on loopback (opencode's documented default — serve.ts
+      // only WARNS when OPENCODE_SERVER_PASSWORD is unset). The real boundary is the
+      // 127.0.0.1 bind.
+      const child = spawn(this.opencodeBinary, ['serve', '--hostname', '127.0.0.1', '--port', String(port)], {
+        stdio: ['ignore', 'pipe', 'pipe'],
+        env: { ...process.env },
+      });
+      this.childProc = child;
+      this.serverPort = port;
+
+      // Child lifetime is the backend's (the pool's), NOT a request's. On unexpected
+      // exit we recover: settle in-flight turns, mark sessions crashed (the backend's
+      // onServerDown), reclaim the port, and reset state so the next ensureServer
+      // re-spawns.
+      child.on('exit', (code, signal) => {
+        // Only react to THIS child's exit (a restart may have swapped in a new one).
+        if (this.childProc !== child) return;
+        this.handleCrash(code, signal, port);
+      });
+
+      await waitForReady(child, READY_TIMEOUT_MS);
+
+      this.opencodeClient = createOpencodeClient({ baseUrl: `http://127.0.0.1:${port}` });
+      this.up = true;
+      this.log.info({ port }, 'opencode-server: ready');
+    } finally {
+      this.startInFlight = false;
+    }
+  }
+
+  /**
+   * Server down (crash-exit or forced restart): reset process/port state, delegate
+   * session-level recovery to the backend, and reclaim the port. Mirrors the
+   * original `handleServerCrash` ordering (up=false → session cleanup → client/
+   * serverStarting null → reclaimPort).
+   */
+  private handleCrash(code: number | null, signal: NodeJS.Signals | null, port: number): void {
+    this.up = false;
+    this.hooks.onServerDown({ code, signal, port });
+    this.opencodeClient = null;
+    this.serverStarting = null; // force a re-spawn on the next ensureServer
+    // Reclaim the port so a re-spawn on a fixed/leaked port isn't blocked. Best
+    // effort; the next start uses a fresh ephemeral port anyway.
+    reclaimPort(port);
+  }
+
+  /**
+   * Phase 3 proactive health monitor (openchamber `runHealthCheckCycle` lift,
+   * busy-aware). Probes /global/health; on a sustained failure of a NON-busy server,
+   * force a restart so the next turn isn't blocked by a wedged process. Busy servers
+   * are deferred via the stale-grace in `decideRestart`. No-op when never started or
+   * a restart is already in flight.
+   */
+  async tickHealth(now: number = Date.now()): Promise<void> {
+    if (!this.childProc || this.restarting) return;
+    const childExited = this.childProc.exitCode !== null || this.childProc.signalCode !== null;
+    // An exited child is recovered lazily by ensureServer; don't double-restart it.
+    if (childExited) return;
+
+    const healthy = await this.probeHealth();
+    if (healthy) {
+      this.consecutiveHealthFailures = 0;
+      this.unhealthyBusySince = 0;
+      return;
+    }
+    this.consecutiveHealthFailures += 1;
+    const busy = this.hooks.isBusy();
+    const decision = decideRestart({
+      processExited: false,
+      consecutiveFailures: this.consecutiveHealthFailures,
+      busy,
+      unhealthyBusySince: this.unhealthyBusySince,
+      now,
+      failureThreshold: DEFAULT_HEALTH_FAILURE_THRESHOLD,
+    });
+    // Stamp the start of an unhealthy-while-busy window so the stale-grace can fire.
+    if (busy && this.unhealthyBusySince === 0) this.unhealthyBusySince = now;
+    if (decision.action === 'restart') {
+      this.log.warn(
+        { failures: this.consecutiveHealthFailures, busy, reason: decision.reason },
+        'opencode-server: health monitor forcing restart',
+      );
+      this.consecutiveHealthFailures = 0;
+      this.unhealthyBusySince = 0;
+      await this.restartServer();
+    }
+  }
+
+  private async probeHealth(): Promise<boolean> {
+    if (!this.opencodeClient) return false;
+    try {
+      const res = await this.opencodeClient.global.health();
+      return !res.error;
+    } catch {
+      return false;
+    }
+  }
+
+  /** Force-kill the current server + reclaim its port; the next ensureServer
+   *  re-spawns (lazy). Mirrors handleCrash's state reset but is initiated by the
+   *  health monitor rather than the OS. */
+  private async restartServer(): Promise<void> {
+    if (this.restarting) return this.restarting;
+    this.restarting = (async () => {
+      const child = this.childProc;
+      const port = this.serverPort;
+      this.up = false;
+      // Fail in-flight turns + mark sessions crashed via the same path as a crash.
+      if (child) {
+        this.handleCrash(null, null, port ?? 0);
+        if (!child.killed) child.kill('SIGTERM');
+      }
+      if (port) {
+        reclaimPort(port);
+        await waitForPortRelease(port, 3_000);
+      }
+      this.childProc = null;
+    })().finally(() => {
+      this.restarting = null;
+    });
+    return this.restarting;
+  }
+
+  /** Full teardown of the child + client + port state. */
+  async dispose(): Promise<void> {
+    this.up = false;
+    const child = this.childProc;
+    this.childProc = null;
+    this.opencodeClient = null;
+    if (child && !child.killed) {
+      child.kill('SIGTERM');
+      const t = setTimeout(() => {
+        if (!child.killed) child.kill('SIGKILL');
+      }, 5_000);
+      t.unref();
+    }
+  }
+}
+
+/** Resolve when the child prints the ready line; reject on timeout or early exit. */
+function waitForReady(child: ChildProcess, timeoutMs: number): Promise<void> {
+  return new Promise((resolve, reject) => {
+    let done = false;
+    let stderrBuf = '';
+
+    const finish = (err?: Error) => {
+      if (done) return;
+      done = true;
+      clearTimeout(timer);
+      child.stdout?.off('data', onOut);
+      child.stderr?.off('data', onErr);
+      child.off('exit', onExit);
+      if (err) reject(err);
+      else resolve();
+    };
+
+    const onOut = (buf: Buffer) => {
+      if (buf.toString().includes('opencode server listening on')) finish();
+    };
+    const onErr = (buf: Buffer) => {
+      stderrBuf += buf.toString();
+    };
+    const onExit = (code: number | null) =>
+      finish(new Error(`opencode serve exited before ready (code ${code}); stderr: ${stderrBuf.slice(-2000)}`));
+    const timer = setTimeout(
+      () => finish(new Error(`opencode serve not ready in ${timeoutMs}ms; stderr: ${stderrBuf.slice(-2000)}`)),
+      timeoutMs,
+    );
+
+    child.stdout?.on('data', onOut);
+    child.stderr?.on('data', onErr);
+    child.on('exit', onExit);
+  });
+}

apps/coder/src/services/backends/opencode-server.ts

@@ -0,0 +1,607 @@
+/**
+ * v2.6 Phase 1 — OpenCodeServerBackend (slimmed, v2.7 audit reshape).
+ *
+ * Warm, multi-turn backend for the `opencode` agent. One `opencode serve` HTTP
+ * server per BooCoder process; one opencode session per BooCode session (resumed
+ * on switch-back); one SSE read loop PER session, each scoped to that session's
+ * worktree directory so sessions in different directories stream concurrently.
+ *
+ * This file is now just the `AgentBackend` SURFACE — ensureSession / prompt /
+ * accumulateUsage / closeSession + the per-session demux side effects (watchdog,
+ * reconcile, usage). It composes three extracted collaborators:
+ *   - `OpenCodeServerSupervisor` (opencode-server-process.ts) — child/client/port/
+ *     health lifecycle, spawn/crash/restart/dispose.
+ *   - the per-session SSE loop (opencode-sse.ts) — subscribe + reconnect/backoff.
+ *   - the pure event map (opencode-event-map.ts) — Event → AgentEvent translation,
+ *     dedup gate, dcp-strip, tool-snapshot.
+ *
+ * Implements the Phase 0 `AgentBackend` interface. Emits transport-agnostic
+ * `AgentEvent`s; the dispatcher maps them to WS frames.
+ *
+ * Spec: openspec/changes/v2-6-persistent-agent-sessions/design.md §2 / §2a.
+ */
+import { createHash } from 'node:crypto';
+import type { FastifyBaseLogger } from 'fastify';
+import type { Event, AssistantMessage } from '@opencode-ai/sdk/v2/client';
+import type { Sql } from '../../db.js';
+import { armAbortGuard, noteTurnActivity, consumeTerminal } from './turn-guard.js';
+import { stepEndedToUsage, type StepUsage } from './opencode-usage.js';
+import { OpenCodeServerSupervisor, type ServerDownInfo } from './opencode-server-process.js';
+import {
+  startSessionEventLoop,
+  type SessionState,
+  type TurnState,
+  type SseLoopDeps,
+} from './opencode-sse.js';
+import {
+  classifyPartDelta,
+  classifyUpdatedPart,
+  toolCalledSnapshot,
+  toolSuccessSnapshot,
+  toolFailedSnapshot,
+  stripDcpTags,
+  errMsg,
+  errToString,
+} from './opencode-event-map.js';
+import type {
+  AgentBackend,
+  AgentSessionHandle,
+  EnsureSessionOpts,
+  PromptCtx,
+  TurnResult,
+} from '../agent-backend.js';
+
+/**
+ * No-activity backstop for an in-flight turn. opencode streams reasoning/text/tool
+ * deltas continuously while working, so "zero events for this long" means the turn
+ * is wedged or its terminal event (session.idle) was lost. Generous so a
+ * legitimately slow turn never trips it.
+ */
+const TURN_INACTIVITY_MS = 180_000;
+
+export interface OpenCodeServerBackendDeps {
+  sql: Sql;
+  log: FastifyBaseLogger;
+  /** Absolute path to the opencode binary (resolved from available_agents at wiring time, Phase 1.7). */
+  opencodeBinary: string;
+}
+
+export class OpenCodeServerBackend implements AgentBackend {
+  readonly backend = 'opencode_server' as const;
+
+  private readonly sql: Sql;
+  private readonly log: FastifyBaseLogger;
+  private readonly supervisor: OpenCodeServerSupervisor;
+
+  /** opencode session id → demux state. Maintained by ensureSession; read by the SSE loop. */
+  private readonly byOpencodeId = new Map<string, SessionState>();
+  /** Coalesces concurrent ensureSession calls for the same (chat, agent) key. */
+  private readonly ensuring = new Map<string, Promise<AgentSessionHandle>>();
+
+  constructor(deps: OpenCodeServerBackendDeps) {
+    this.sql = deps.sql;
+    this.log = deps.log;
+    this.supervisor = new OpenCodeServerSupervisor({
+      opencodeBinary: deps.opencodeBinary,
+      log: deps.log,
+      hooks: {
+        isBusy: () => this.isBusy(),
+        onServerDown: (info) => this.onServerDown(info),
+      },
+    });
+  }
+
+  /** §2: liveness for the health endpoint + dispatcher fallback decision. */
+  health(): 'up' | 'down' {
+    return this.supervisor.health();
+  }
+
+  /** Phase 3: busy iff ANY pooled opencode session has an in-flight turn. */
+  isBusy(): boolean {
+    for (const st of this.byOpencodeId.values()) {
+      if (st.activeTurn) return true;
+    }
+    return false;
+  }
+
+  /** Phase 3 proactive health probe + busy-aware self-restart, run by the pool's
+   *  periodic sweep. Delegates to the supervisor. */
+  async tickHealth(now: number = Date.now()): Promise<void> {
+    await this.supervisor.tickHealth(now);
+  }
+
+  /**
+   * Server down (crash-exit or forced restart): fail every in-flight turn so its
+   * dispatcher unblocks, mark each session crashed so ensureSession won't resume a
+   * now-dead native id, and tear down the SSE loops + demux state. Invoked by the
+   * supervisor (it owns the process/port reset). Mirrors the original
+   * handleServerCrash session-half byte-for-byte.
+   */
+  private onServerDown(info: ServerDownInfo): void {
+    const states = [...this.byOpencodeId.values()];
+    this.log.warn(
+      { code: info.code, signal: info.signal, port: info.port, liveSessions: states.length },
+      'opencode-server: child exited — recovering (fail in-flight, mark crashed, re-spawn next turn)',
+    );
+
+    const crashedIds: string[] = [];
+    for (const st of states) {
+      st.sseAbort?.abort();
+      if (st.activeTurn) {
+        st.activeTurn.settle({ ok: false, error: 'opencode server crashed mid-turn' });
+        st.activeTurn = null;
+      }
+      if (st.watchdog) {
+        clearTimeout(st.watchdog);
+        st.watchdog = null;
+      }
+      crashedIds.push(st.agentSessionId);
+    }
+    // Drop the demux map: every session id is stale against a fresh server.
+    this.byOpencodeId.clear();
+
+    if (crashedIds.length > 0) {
+      this.sql`
+        UPDATE agent_sessions SET status = 'crashed'
+        WHERE agent_session_id = ANY(${crashedIds}) AND status <> 'closed'
+      `.catch((err) => {
+        this.log.warn({ err: errMsg(err) }, 'opencode-server: failed to mark crashed sessions (non-fatal)');
+      });
+    }
+  }
+
+  // ─── SSE loop wiring ─────────────────────────────────────────────────────────
+
+  /** The dependency bundle the per-session SSE loop reads. */
+  private sseDeps(): SseLoopDeps {
+    return {
+      isUp: () => this.supervisor.isUp(),
+      getClient: () => this.supervisor.client,
+      dispatchEvent: (ev) => this.dispatchEvent(ev),
+      reconcile: (st) => this.reconcile(st),
+      onReconnectGiveUp: (st) => this.onReconnectGiveUp(st),
+      log: this.log,
+    };
+  }
+
+  /** Demux one event to the owning session's active turn. Unknown/between-turns → drop. */
+  private dispatchEvent(ev: Event): void {
+    switch (ev.type) {
+      // ─── session.next.* — live streaming events (the primary path) ─────────
+      case 'session.next.text.delta': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        const cleaned = stripDcpTags(p.delta);
+        if (cleaned) st.activeTurn.onEvent({ type: 'text', text: cleaned });
+        return;
+      }
+      case 'session.next.reasoning.delta': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        st.activeTurn.onEvent({ type: 'reasoning', text: p.delta });
+        return;
+      }
+      case 'session.next.tool.called': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        st.activeTurn.onEvent({ type: 'tool_call', toolCall: toolCalledSnapshot(p) });
+        return;
+      }
+      case 'session.next.tool.success': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        st.activeTurn.onEvent({ type: 'tool_update', toolCall: toolSuccessSnapshot(p) });
+        return;
+      }
+      case 'session.next.tool.failed': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        st.activeTurn.onEvent({ type: 'tool_update', toolCall: toolFailedSnapshot(p) });
+        return;
+      }
+      // ─── per-step usage (U.6) — token/cost accounting for opencode sessions ──
+      case 'session.next.step.ended': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        // Accumulate this step's normalized usage onto the (chat_id, agent) row.
+        // Fire-and-forget: a DB hiccup must not stall the turn.
+        const usage = stepEndedToUsage(p);
+        void this.accumulateUsage(st, usage);
+        return;
+      }
+      // ─── message.part.* — terminal/post-hoc events (dedup gate) ────────────
+      case 'message.part.delta': {
+        const p = ev.properties;
+        const st = this.byOpencodeId.get(p.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        const e = classifyPartDelta(p, st);
+        if (e) st.activeTurn.onEvent(e);
+        return;
+      }
+      case 'message.part.updated': {
+        const part = ev.properties.part;
+        const st = this.byOpencodeId.get(part.sessionID);
+        if (!st?.activeTurn) return;
+        this.bumpActivity(st);
+        const e = classifyUpdatedPart(part, st);
+        if (e) st.activeTurn.onEvent(e);
+        return;
+      }
+      // ─── lifecycle ─────────────────────────────────────────────────────────
+      case 'session.idle': {
+        const st = this.byOpencodeId.get(ev.properties.sessionID);
+        if (!st) return;
+        if (consumeTerminal(st) === 'swallow') return; // F.1: drop the post-abort orphan
+        st.activeTurn?.settle({ ok: true });
+        return;
+      }
+      case 'session.error': {
+        const sid = ev.properties.sessionID;
+        if (!sid) return;
+        const st = this.byOpencodeId.get(sid);
+        if (!st) return;
+        if (consumeTerminal(st) === 'swallow') return; // F.1: drop the post-abort orphan
+        st.activeTurn?.settle({ ok: false, error: errToString(ev.properties.error) });
+        return;
+      }
+      default:
+        return;
+    }
+  }
+
+  // ─── turn-completion resilience (watchdog + reconnect reconcile) ─────────────
+
+  /** Reset the inactivity backstop on any event routed to a session's active turn. */
+  private bumpActivity(st: SessionState): void {
+    if (!st.activeTurn) return;
+    // A live turn is producing → the post-abort orphan-terminal window is over.
+    noteTurnActivity(st);
+    if (st.watchdog) clearTimeout(st.watchdog);
+    st.watchdog = setTimeout(() => {
+      void this.onTurnStall(st);
+    }, TURN_INACTIVITY_MS);
+    st.watchdog.unref?.();
+  }
+
+  /** Watchdog fired: reconcile once; if still-running we can't tell, so fail closed.
+   *  Also mark the agent_sessions row crashed so a stale session isn't resumed. */
+  private async onTurnStall(st: SessionState): Promise<void> {
+    const settled = await this.reconcile(st);
+    if (!settled) {
+      this.log.warn({ agentSessionId: st.agentSessionId }, 'opencode-server: turn stalled (no activity), failing + marking crashed');
+      await this.sql`
+        UPDATE agent_sessions SET status = 'crashed'
+        WHERE agent_session_id = ${st.agentSessionId}
+      `.catch(() => {});
+      st.activeTurn?.settle({ ok: false, error: 'turn timed out (no activity)' });
+    }
+  }
+
+  /** SSE circuit-breaker fired (reconnect gave up): fail the active turn + mark the
+   *  session crashed so it isn't resumed. The next turn re-creates a fresh session. */
+  private async onReconnectGiveUp(st: SessionState): Promise<void> {
+    if (!st.activeTurn) return;
+    await this.sql`
+      UPDATE agent_sessions SET status = 'crashed'
+      WHERE agent_session_id = ${st.agentSessionId}
+    `.catch(() => {});
+    st.activeTurn?.settle({ ok: false, error: 'opencode SSE stream lost (reconnect gave up)' });
+  }
+
+  /**
+   * Ask the server whether this session's turn already finished — recovers a
+   * session.idle/error lost during an SSE gap. Returns true if it settled the turn.
+   */
+  private async reconcile(st: SessionState): Promise<boolean> {
+    const turn = st.activeTurn;
+    const client = this.supervisor.client;
+    if (!turn || !client) return false;
+    try {
+      const res = await client.session.messages({
+        sessionID: st.agentSessionId,
+        directory: st.worktreePath,
+      });
+      if (res.error || !res.data) return false;
+      let lastAssistant: AssistantMessage | undefined;
+      for (let i = res.data.length - 1; i >= 0; i--) {
+        const info = res.data[i]!.info;
+        if (info.role === 'assistant') {
+          lastAssistant = info;
+          break;
+        }
+      }
+      if (!lastAssistant) return false;
+      if (lastAssistant.error != null) {
+        turn.settle({ ok: false, error: errToString(lastAssistant.error) });
+        return true;
+      }
+      if (lastAssistant.time.completed != null) {
+        turn.settle({ ok: true });
+        return true;
+      }
+      return false; // still running — the live stream will deliver session.idle
+    } catch {
+      return false; // inconclusive — watchdog backstop covers it
+    }
+  }
+
+  // ─── per-step usage persistence (U.6) ────────────────────────────────────────
+
+  /**
+   * Accumulate one `session.next.step.ended`'s normalized usage onto the session's
+   * agent_sessions row. Running totals for the whole conversation context. Zero-delta
+   * steps are skipped. Errors are swallowed: usage telemetry must never fail a turn.
+   */
+  private async accumulateUsage(st: SessionState, u: StepUsage): Promise<void> {
+    if (u.input === 0 && u.output === 0 && u.cost === 0) return;
+    try {
+      await this.sql`
+        UPDATE agent_sessions SET
+          input_tokens = input_tokens + ${u.input},
+          output_tokens = output_tokens + ${u.output},
+          cost = cost + ${u.cost}
+        WHERE agent_session_id = ${st.agentSessionId}
+      `;
+    } catch (err) {
+      this.log.warn(
+        { err: errMsg(err), agentSessionId: st.agentSessionId },
+        'opencode-server: failed to persist step usage (non-fatal)',
+      );
+    }
+  }
+
+  // ─── ensureSession: create-or-resume against agent_sessions (1.5) ────────────
+
+  async ensureSession(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle> {
+    // Coalesce concurrent first-turns for the same (chat, agent) so the SELECT…
+    // create…upsert can't race into two opencode sessions (the second orphaning
+    // the first). A single (non-concurrent) call is unaffected — the entry is set
+    // and removed within this call. Defensive: the dispatcher already serializes
+    // turns per (chat, agent) via its inflight map.
+    const key = `${opts.chatId}:${opts.agent}`;
+    const existing = this.ensuring.get(key);
+    if (existing) return existing;
+    const p = this.ensureSessionInner(sessionId, opts).finally(() => {
+      if (this.ensuring.get(key) === p) this.ensuring.delete(key);
+    });
+    this.ensuring.set(key, p);
+    return p;
+  }
+
+  private async ensureSessionInner(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle> {
+    await this.supervisor.ensureServer();
+    const client = this.supervisor.client;
+    if (!client) throw new Error('opencode-server: client not ready after ensureServer');
+
+    const configHash = sessionConfigHash(opts.model);
+    // P1.5-b: agent_sessions is keyed (chat_id, agent) — the tab/chat is the
+    // context unit (two tabs in one session = two contexts sharing one worktree).
+    const [row] = await this.sql<{ agent_session_id: string | null; status: string; config_hash: string | null }[]>`
+      SELECT agent_session_id, status, config_hash FROM agent_sessions
+      WHERE chat_id = ${opts.chatId} AND agent = ${opts.agent}
+    `;
+    let agentSessionId = row?.agent_session_id ?? null;
+
+    // Don't resume crashed sessions or sessions whose config drifted (model change).
+    const shouldResume = agentSessionId
+      && row!.status !== 'crashed'
+      && (row!.config_hash == null || row!.config_hash === configHash);
+
+    if (!shouldResume) {
+      if (agentSessionId) {
+        this.log.info({ sessionId, oldStatus: row!.status, hashMatch: row!.config_hash === configHash },
+          'opencode-server: not resuming stale session, creating fresh');
+        this.byOpencodeId.delete(agentSessionId);
+      }
+      const created = await client.session.create({ directory: opts.worktreePath });
+      if (created.error || !created.data) {
+        throw new Error(`opencode-server: session.create failed: ${errToString(created.error)}`);
+      }
+      agentSessionId = created.data.id;
+      await this.sql`
+        INSERT INTO agent_sessions
+          (chat_id, session_id, worktree_id, agent, backend, agent_session_id, server_port, status, last_active_at, config_hash)
+        VALUES
+          (${opts.chatId}, ${sessionId}, ${opts.worktreeId}, ${opts.agent}, 'opencode_server', ${agentSessionId}, ${this.supervisor.port}, 'active', clock_timestamp(), ${configHash})
+        ON CONFLICT (chat_id, agent) DO UPDATE SET
+          session_id = EXCLUDED.session_id,
+          worktree_id = EXCLUDED.worktree_id,
+          backend = 'opencode_server',
+          agent_session_id = EXCLUDED.agent_session_id,
+          server_port = EXCLUDED.server_port,
+          status = 'active',
+          last_active_at = clock_timestamp(),
+          config_hash = EXCLUDED.config_hash
+      `;
+    } else {
+      await this.sql`
+        UPDATE agent_sessions
+        SET status = 'active', last_active_at = clock_timestamp(), server_port = ${this.supervisor.port}, config_hash = ${configHash}
+        WHERE chat_id = ${opts.chatId} AND agent = ${opts.agent}
+      `;
+    }
+
+    // Both branches above guarantee agentSessionId is non-null.
+    const ocSessionId = agentSessionId!;
+
+    // Register / refresh the demux entry the SSE loop keys on. Preserve an existing
+    // entry (and any in-flight turn) — just refresh the routing fields.
+    let state = this.byOpencodeId.get(ocSessionId);
+    if (state) {
+      state.boocodeSessionId = sessionId;
+      state.worktreePath = opts.worktreePath;
+    } else {
+      state = this.makeSessionState(sessionId, ocSessionId, opts.worktreePath);
+      this.byOpencodeId.set(ocSessionId, state);
+    }
+
+    // Start this session's own SSE loop, scoped to its worktree directory. Both
+    // fresh-create and resume reach here; idempotent.
+    startSessionEventLoop(state, this.sseDeps());
+
+    return {
+      sessionId,
+      agent: opts.agent,
+      backend: 'opencode_server',
+      chatId: opts.chatId,
+      worktreeId: opts.worktreeId,
+      agentSessionId: ocSessionId,
+      serverPort: this.supervisor.port,
+    };
+  }
+
+  /** Fresh per-(opencode session) demux state. */
+  private makeSessionState(boocodeSessionId: string, agentSessionId: string, worktreePath: string): SessionState {
+    return {
+      boocodeSessionId,
+      agentSessionId,
+      worktreePath,
+      streamedPartKeys: new Set(),
+      partTypeById: new Map(),
+      activeTurn: null,
+      watchdog: null,
+      sseAbort: null,
+      swallowNextTerminal: false,
+    };
+  }
+
+  // ─── prompt: send one turn (1.6) ─────────────────────────────────────────────
+
+  async prompt(handle: AgentSessionHandle, input: string, ctx: PromptCtx): Promise<TurnResult> {
+    const client = this.supervisor.client;
+    if (!client) throw new Error('opencode-server: client not ready');
+    const oc = handle.agentSessionId;
+    if (!oc) throw new Error('opencode-server: handle has no agentSessionId');
+
+    let state = this.byOpencodeId.get(oc);
+    if (!state) {
+      state = this.makeSessionState(handle.sessionId, oc, ctx.worktreePath);
+      this.byOpencodeId.set(oc, state);
+    }
+    const session = state;
+
+    // v2.7 busy-assert: one in-flight turn per session. The dispatcher serializes
+    // turns per (chat, agent), so this never fires in normal dispatch — but if a
+    // second prompt arrives while one is live it would silently overwrite the slot
+    // and orphan the first turn, so reject instead.
+    if (session.activeTurn) {
+      return { ok: false, error: 'opencode-server: session already has an in-flight turn' };
+    }
+
+    // Authoritative per-turn directory for SDK routing + reconcile.
+    session.worktreePath = ctx.worktreePath;
+    // Defensive: ensureSession normally starts the loop, but if prompt is reached
+    // with a freshly-created state (no loop yet), start it so the turn streams.
+    startSessionEventLoop(session, this.sseDeps());
+
+    return await new Promise<TurnResult>((resolve) => {
+      let settled = false;
+      const cleanup = () => {
+        session.activeTurn = null;
+        if (session.watchdog) {
+          clearTimeout(session.watchdog);
+          session.watchdog = null;
+        }
+        session.streamedPartKeys.clear();
+        session.partTypeById.clear();
+        ctx.signal.removeEventListener('abort', onAbort);
+      };
+      const settle = (r: TurnResult) => {
+        if (settled) return;
+        settled = true;
+        cleanup();
+        resolve(r);
+      };
+      const onAbort = () => {
+        // Abort the turn only — never the server.
+        client.session.abort({ sessionID: oc, directory: ctx.worktreePath }).catch(() => {});
+        // F.1: opencode emits one trailing session.idle/error for the cancelled
+        // turn — arm the guard so it's swallowed, not used to settle the next turn.
+        armAbortGuard(session);
+        settle({ ok: false, error: 'aborted' });
+      };
+
+      const turn: TurnState = { onEvent: ctx.onEvent, settle };
+      session.activeTurn = turn;
+      this.bumpActivity(session); // arm the inactivity backstop
+
+      if (ctx.signal.aborted) {
+        onAbort();
+        return;
+      }
+      ctx.signal.addEventListener('abort', onAbort, { once: true });
+
+      const model = parseModel(ctx.model);
+      client.session
+        .promptAsync({
+          sessionID: oc,
+          directory: ctx.worktreePath,
+          parts: [{ type: 'text', text: input }],
+          ...(model ? { model } : {}),
+        })
+        .then((res) => {
+          // promptAsync is fire-and-forget (204); the turn completes via session.idle.
+          // Only a submission error settles here.
+          if (res.error) settle({ ok: false, error: errToString(res.error) });
+        })
+        .catch((err) => settle({ ok: false, error: errMsg(err) }));
+    });
+  }
+
+  // ─── teardown ────────────────────────────────────────────────────────────────
+
+  async closeSession(handle: AgentSessionHandle): Promise<void> {
+    if (handle.agentSessionId) {
+      // Stop this session's SSE loop before dropping its demux entry.
+      this.byOpencodeId.get(handle.agentSessionId)?.sseAbort?.abort();
+      this.byOpencodeId.delete(handle.agentSessionId);
+    }
+    await this.sql`
+      UPDATE agent_sessions SET status = 'closed'
+      WHERE chat_id = ${handle.chatId} AND agent = ${handle.agent}
+    `.catch(() => {});
+  }
+
+  async dispose(): Promise<void> {
+    // Abort every per-session SSE loop so none survive the teardown.
+    for (const st of this.byOpencodeId.values()) st.sseAbort?.abort();
+    this.byOpencodeId.clear();
+    await this.supervisor.dispose();
+  }
+}
+
+// ─── helpers ──────────────────────────────────────────────────────────────────
+
+/** BooCoder model string "provider/model" → opencode's structured {providerID, modelID}. */
+function parseModel(model: string | undefined): { providerID: string; modelID: string } | undefined {
+  if (!model || !model.trim()) return undefined;
+  const trimmed = model.trim();
+  const idx = trimmed.indexOf('/');
+  if (idx > 0 && idx < trimmed.length - 1) {
+    return { providerID: trimmed.slice(0, idx), modelID: trimmed.slice(idx + 1) };
+  }
+  // No slash but non-empty → infer llama-swap (the only configured provider).
+  if (idx < 0 && trimmed.length > 0) {
+    return { providerID: 'llama-swap', modelID: trimmed };
+  }
+  return undefined;
+}
+
+/** Hash of stable config — detects model changes across sessions without
+ *  invalidating on ephemeral state like the random server port. */
+function sessionConfigHash(model: string): string {
+  return createHash('sha256').update(`opencode_server|${model}`).digest('hex').slice(0, 16);
+}

apps/coder/src/services/backends/opencode-sse.ts

@@ -0,0 +1,181 @@
+/**
+ * Per-session SSE subscribe loop + reconnect/backoff + eventSessionId demux.
+ *
+ * Extracted (v2.7 audit reshape) from `OpenCodeServerBackend.startSessionEventLoop`
+ * / `runSessionEventLoop`. opencode scopes events by the `directory` query param, so
+ * each session runs its own dir-scoped stream and never drops a sibling's events.
+ *
+ * The loop is intentionally thin: it owns subscribe + the demux filter + reconnect
+ * timing only. Translating an event into turn side effects (watchdog, usage,
+ * settle) stays on the backend via the injected `dispatchEvent` / `reconcile`
+ * callbacks — `opencode-sse` knows nothing about turns or the DB.
+ *
+ * v2.7 concurrency hardening: the throw-driven reconnect path now backs off
+ * exponentially and trips a circuit-breaker (`onReconnectGiveUp`) after a bounded
+ * number of consecutive failures, instead of looping forever at a flat 1s. The
+ * HAPPY PATH is unchanged — a clean stream end (server still up) reconnects after
+ * `baseMs` (1s, as before) and resets the failure counter, so a long-lived session
+ * that re-subscribes normally never backs off.
+ */
+import type { FastifyBaseLogger } from 'fastify';
+import type { Event, OpencodeClient } from '@opencode-ai/sdk/v2/client';
+import type { AgentEvent } from '../agent-backend.js';
+import type { TurnResult } from '../agent-backend.js';
+import { eventSessionId, errMsg } from './opencode-event-map.js';
+
+export const SSE_RECONNECT_DELAY_MS = 1_000;
+
+/** One in-flight turn's emitter + completion settler. */
+export interface TurnState {
+  onEvent: (e: AgentEvent) => void;
+  settle: (r: TurnResult) => void;
+}
+
+/** Per-(opencode session) demux state. dedup sets scoped here, cleared per turn. */
+export interface SessionState {
+  boocodeSessionId: string;
+  agentSessionId: string;
+  /** Worktree directory for SDK `directory` routing; refreshed each turn from ctx. */
+  worktreePath: string;
+  /** dedup gate: `${type}:${id}` added on delta, deleted-and-tested on updated. Cleared at turn end. */
+  streamedPartKeys: Set<string>;
+  /** partID → 'text' | 'reasoning', so a delta with a non-'reasoning' field is still classed right. Cleared at turn end. */
+  partTypeById: Map<string, string>;
+  activeTurn: TurnState | null;
+  /** Inactivity backstop timer for the active turn; null when no turn in flight. */
+  watchdog: ReturnType<typeof setTimeout> | null;
+  /** Per-session SSE subscription handle. Non-null while the loop is running;
+   *  aborting it tears down the underlying fetch and exits the loop. */
+  sseAbort: AbortController | null;
+  /** F.1 post-abort orphan-terminal guard: swallow the one session.idle/error
+   *  opencode emits for an aborted turn so it can't settle the next turn. */
+  swallowNextTerminal: boolean;
+}
+
+// ─── reconnect backoff (pure) ────────────────────────────────────────────────
+
+export interface ReconnectPolicy {
+  /** First retry delay (and the steady-state clean-reconnect delay). */
+  baseMs: number;
+  /** Cap on the exponential delay. */
+  maxMs: number;
+  /** Consecutive failures tolerated before the breaker trips (give up). */
+  maxAttempts: number;
+}
+
+export const DEFAULT_RECONNECT_POLICY: ReconnectPolicy = {
+  baseMs: SSE_RECONNECT_DELAY_MS,
+  maxMs: 30_000,
+  maxAttempts: 6,
+};
+
+export type ReconnectDecision =
+  | { action: 'reconnect'; delayMs: number }
+  | { action: 'give-up' };
+
+/**
+ * Pure backoff decision after `failures` consecutive throwing reconnect attempts
+ * (1-based: the first failure passes `failures=1`). Returns an exponentially
+ * growing delay capped at `maxMs`, or `give-up` once the count exceeds
+ * `maxAttempts`. `failures=1` yields `baseMs`, so the very first retry matches the
+ * pre-hardening flat delay (happy-path-preserving).
+ */
+export function reconnectDecision(
+  failures: number,
+  policy: ReconnectPolicy = DEFAULT_RECONNECT_POLICY,
+): ReconnectDecision {
+  if (failures > policy.maxAttempts) return { action: 'give-up' };
+  const exp = policy.baseMs * 2 ** (failures - 1);
+  return { action: 'reconnect', delayMs: Math.min(policy.maxMs, exp) };
+}
+
+// ─── the loop ────────────────────────────────────────────────────────────────
+
+export interface SseLoopDeps {
+  /** Live iff the server is up (read each iteration so a crash stops the loop). */
+  isUp: () => boolean;
+  /** The current opencode client (null between server restarts). */
+  getClient: () => OpencodeClient | null;
+  /** Route one demuxed event to its turn (backend side effects live here). */
+  dispatchEvent: (ev: Event) => void;
+  /** Recover an idle/error lost during an SSE gap. Returns true if it settled. */
+  reconcile: (state: SessionState) => Promise<boolean>;
+  /** Circuit-breaker: called once the backoff gives up; fail the active turn. */
+  onReconnectGiveUp: (state: SessionState) => Promise<void> | void;
+  log: FastifyBaseLogger;
+  /** Injectable for tests; defaults to a real timer sleep. */
+  sleep?: (ms: number) => Promise<void>;
+  policy?: ReconnectPolicy;
+}
+
+function defaultSleep(ms: number): Promise<void> {
+  return new Promise((r) => setTimeout(r, ms));
+}
+
+/** Per-session SSE subscription, scoped to the session's worktree directory.
+ *  Idempotent: a no-op if this session's loop is already running. */
+export function startSessionEventLoop(state: SessionState, deps: SseLoopDeps): void {
+  if (state.sseAbort) return; // already running
+  const abort = new AbortController();
+  state.sseAbort = abort;
+  void runSessionEventLoop(state, abort, deps).finally(() => {
+    // Only clear if this controller is still the live one (a later restart may
+    // have already installed a new one).
+    if (state.sseAbort === abort) state.sseAbort = null;
+  });
+}
+
+export async function runSessionEventLoop(
+  state: SessionState,
+  abort: AbortController,
+  deps: SseLoopDeps,
+): Promise<void> {
+  const signal = abort.signal;
+  const sleep = deps.sleep ?? defaultSleep;
+  const policy = deps.policy ?? DEFAULT_RECONNECT_POLICY;
+  let failures = 0;
+  while (deps.isUp() && deps.getClient() && !signal.aborted) {
+    const client = deps.getClient()!;
+    try {
+      // Re-read worktreePath each (re)subscribe so a directory refresh is picked
+      // up on reconnect. Passing `signal` lets close/dispose tear down a stream
+      // that's parked in `for await` between events.
+      const sub = await client.event.subscribe({ directory: state.worktreePath }, { signal });
+      for await (const ev of sub.stream) {
+        if (signal.aborted) break;
+        // Dir-scoped streams should only carry this session's events, but two
+        // sessions sharing a worktree (possible post-P1.5-b) each receive BOTH
+        // sessions' events — so drop anything that isn't ours, else the other
+        // session's deltas get processed twice (once per loop).
+        const sid = eventSessionId(ev);
+        if (sid != null && sid !== state.agentSessionId) continue;
+        deps.dispatchEvent(ev);
+      }
+      // Clean stream end — a healthy reconnect, NOT a failure: recover any lost
+      // terminal then re-subscribe at the base delay (pre-hardening behavior).
+      failures = 0;
+      if (deps.isUp() && !signal.aborted) {
+        await deps.reconcile(state); // recover an idle/error lost during the gap
+        await sleep(policy.baseMs);
+      }
+    } catch (err) {
+      if (!deps.isUp() || signal.aborted) break;
+      failures += 1;
+      const decision = reconnectDecision(failures, policy);
+      deps.log.warn(
+        { err: errMsg(err), agentSessionId: state.agentSessionId, failures, action: decision.action },
+        'opencode-server: session event loop error; reconnecting',
+      );
+      await deps.reconcile(state);
+      if (decision.action === 'give-up') {
+        deps.log.warn(
+          { agentSessionId: state.agentSessionId, failures },
+          'opencode-server: SSE reconnect gave up (circuit breaker) — failing active turn',
+        );
+        await deps.onReconnectGiveUp(state);
+        break;
+      }
+      await sleep(decision.delayMs);
+    }
+  }
+}

apps/coder/src/services/backends/opencode-usage.ts

@@ -0,0 +1,77 @@
+/**
+ * v2.6 Phase 1-UX (U.6) — pure mapper for opencode's per-step usage event.
+ *
+ * opencode's warm server emits `session.next.step.ended` once per completed LLM
+ * step (so a multi-tool turn fires it several times). Its `properties` carry the
+ * step's token + cost accounting:
+ *
+ *   {
+ *     timestamp: number;
+ *     sessionID: string;
+ *     finish: string;
+ *     cost: number;                                  // USD for this step
+ *     tokens: {
+ *       input: number; output: number; reasoning: number;
+ *       cache: { read: number; write: number };
+ *     };
+ *     snapshot?: string;
+ *   }
+ *
+ * (Verified against @opencode-ai/sdk@1.15.12 — `EventSessionNextStepEnded` in
+ * `dist/v2/gen/types.gen.d.ts`, a member of the `Event` union the SSE loop
+ * switches on.)
+ *
+ * We normalize to the review's target slice `{input, output, cost}` (the
+ * provider-agnostic `AgentUsage` shape lands later). cache read/write tokens are
+ * folded into `input` so the persisted input count reflects the real context the
+ * model billed for; reasoning tokens are folded into `output` since that's what
+ * the provider counts them as for generation. This keeps the persisted totals a
+ * faithful sum of what opencode reported, without inventing extra columns yet.
+ */
+
+/** The `properties` shape of a `session.next.step.ended` event (subset we read). */
+export interface StepEndedProps {
+  cost: number;
+  tokens: {
+    input: number;
+    output: number;
+    reasoning: number;
+    cache: { read: number; write: number };
+  };
+}
+
+/** Normalized per-step usage delta persisted onto the agent_sessions row. */
+export interface StepUsage {
+  input: number;
+  output: number;
+  cost: number;
+}
+
+/** Coerce a possibly-missing/NaN number to a non-negative finite integer (tokens). */
+function n(v: unknown): number {
+  const x = typeof v === 'number' ? v : Number(v);
+  return Number.isFinite(x) && x > 0 ? Math.round(x) : 0;
+}
+
+/** Coerce a possibly-missing/NaN number to a non-negative finite float (cost USD). */
+function f(v: unknown): number {
+  const x = typeof v === 'number' ? v : Number(v);
+  return Number.isFinite(x) && x > 0 ? x : 0;
+}
+
+/**
+ * Map a `session.next.step.ended` payload → the normalized `{input, output, cost}`
+ * delta. Defensive against missing/partial token blocks (the wire is trusted but
+ * we never want a NaN to poison the accumulated DB total). `input` folds in cache
+ * read+write; `output` folds in reasoning.
+ */
+export function stepEndedToUsage(props: Partial<StepEndedProps> | undefined): StepUsage {
+  const t = props?.tokens;
+  const cacheRead = n(t?.cache?.read);
+  const cacheWrite = n(t?.cache?.write);
+  return {
+    input: n(t?.input) + cacheRead + cacheWrite,
+    output: n(t?.output) + n(t?.reasoning),
+    cost: f(props?.cost),
+  };
+}

apps/coder/src/services/backends/pushable-iterable.ts

@@ -0,0 +1,96 @@
+/**
+ * claude-sdk-sessionstore #9 (Part 2) — a tiny PURE pushable async-iterable.
+ *
+ * The Claude Agent SDK's streaming-input mode wants `query({ prompt })` where
+ * `prompt` is an `AsyncIterable<SDKUserMessage>`. To keep ONE `query()` generator
+ * alive across many turns (the "warm" property), the backend feeds it ONE user
+ * message per `prompt()` turn through a queue that stays open between turns and is
+ * only closed at `closeSession`/`dispose`. This is that queue.
+ *
+ * Semantics (the bit worth unit-testing — push/close/iterate ordering):
+ *   - `push(v)` enqueues a value. If a consumer is parked in `await next()`, it's
+ *     handed the value immediately; otherwise the value buffers in FIFO order.
+ *   - The async iterator yields buffered/pushed values in push order, and PARKS
+ *     (never busy-loops) when the buffer is empty — so the SDK generator waits for
+ *     the next turn's message instead of seeing end-of-input.
+ *   - `close()` ends the iterable: any parked consumer resolves `{done:true}` and
+ *     all future `next()`s return done. Values pushed after close are dropped.
+ *   - It's single-consumer (one `query()` reads it); concurrent consumers are not a
+ *     supported shape and not needed here.
+ *
+ * No SDK import — generic over the pushed value `T` — so the pure push/close/iterate
+ * ordering is testable without the `SDKUserMessage` shape or a live binary.
+ */
+export interface Pushable<T> {
+  /** Enqueue a value (or hand it to a parked consumer). No-op after close. */
+  push(value: T): void;
+  /** End the iterable. Idempotent; a parked consumer resolves done. */
+  close(): void;
+  /** True once `close()` has been called. */
+  readonly closed: boolean;
+  /** The async-iterable the consumer (the SDK `query`) drives. */
+  readonly iterable: AsyncIterable<T>;
+}
+
+export function createPushable<T>(): Pushable<T> {
+  const buffer: T[] = [];
+  // A waiting consumer's resolver (null when none is parked). Single-consumer.
+  let pendingResolve: ((res: IteratorResult<T>) => void) | null = null;
+  let closed = false;
+
+  function push(value: T): void {
+    if (closed) return;
+    if (pendingResolve) {
+      const resolve = pendingResolve;
+      pendingResolve = null;
+      resolve({ value, done: false });
+      return;
+    }
+    buffer.push(value);
+  }
+
+  function close(): void {
+    if (closed) return;
+    closed = true;
+    if (pendingResolve) {
+      const resolve = pendingResolve;
+      pendingResolve = null;
+      resolve({ value: undefined, done: true });
+    }
+  }
+
+  const iterator: AsyncIterator<T> = {
+    next(): Promise<IteratorResult<T>> {
+      // Drain the buffer first (FIFO), regardless of close — buffered values
+      // pushed before close are still delivered.
+      if (buffer.length > 0) {
+        return Promise.resolve({ value: buffer.shift() as T, done: false });
+      }
+      if (closed) {
+        return Promise.resolve({ value: undefined, done: true });
+      }
+      // Park until the next push/close. Single-consumer: only one waiter at a time.
+      return new Promise<IteratorResult<T>>((resolve) => {
+        pendingResolve = resolve;
+      });
+    },
+    return(): Promise<IteratorResult<T>> {
+      // Consumer abandoned the loop (e.g. `break`) → close so a later push no-ops.
+      close();
+      return Promise.resolve({ value: undefined, done: true });
+    },
+  };
+
+  return {
+    push,
+    close,
+    get closed() {
+      return closed;
+    },
+    iterable: {
+      [Symbol.asyncIterator]() {
+        return iterator;
+      },
+    },
+  };
+}

apps/coder/src/services/backends/turn-guard.ts

@@ -0,0 +1,38 @@
+/**
+ * Guard against opencode's post-abort "orphan" terminal event (F.1).
+ *
+ * When a turn is aborted (`client.session.abort`), opencode emits one trailing
+ * `session.idle` / `session.error` for the cancelled turn. Without a guard that
+ * orphan settles whatever turn currently holds the session slot — which, after
+ * the user immediately sends another message, is the NEXT turn, settling it early
+ * as success (the v2.6.5 Stop-button bug). opencode terminal events carry only a
+ * `sessionID` (no turn id), so we can't match by id; instead we swallow exactly
+ * one terminal per abort, and self-heal if that orphan never arrives.
+ */
+export interface AbortTerminalGuard {
+  /** True between an abort and the orphan terminal event that follows it. */
+  swallowNextTerminal: boolean;
+}
+
+/** Arm on abort: the next terminal event for this session is the orphan. */
+export function armAbortGuard(g: AbortTerminalGuard): void {
+  g.swallowNextTerminal = true;
+}
+
+/**
+ * A new turn produced activity (delta) → the orphan window is over. Self-heals
+ * the case where opencode emits no orphan idle (e.g. abort-before-prompt), so a
+ * real terminal still settles instead of being swallowed forever.
+ */
+export function noteTurnActivity(g: AbortTerminalGuard): void {
+  g.swallowNextTerminal = false;
+}
+
+/** Decide a terminal (idle/error): swallow the post-abort orphan once, else settle. */
+export function consumeTerminal(g: AbortTerminalGuard): 'swallow' | 'settle' {
+  if (g.swallowNextTerminal) {
+    g.swallowNextTerminal = false;
+    return 'swallow';
+  }
+  return 'settle';
+}

apps/coder/src/services/backends/warm-acp-routing.ts

@@ -0,0 +1,41 @@
+/**
+ * v2.6 Phase 2 — warm-vs-one-shot routing predicate for goose/qwen.
+ *
+ * The warm ACP backend keys its persistent process + ACP session on (chat_id,
+ * agent) — exactly like the opencode-server backend. A task therefore only routes
+ * to the warm pool when it carries BOTH a `session_id` and a `chat_id`, i.e. it
+ * came from a real chat tab (the coder message route + skills route stamp both).
+ *
+ * Session-less creators — arena contestants, MCP-created tasks, generic
+ * `POST /api/tasks`, `new_task` — leave one or both null. Those keep the existing
+ * one-shot worktree-per-task ACP path (`runExternalAgent`), which spawns a fresh
+ * `goose acp` / `qwen --acp` per turn and never holds a warm process. Routing them
+ * warm would either synthesize a degenerate (null, agent) key or create a chat per
+ * arena contestant — neither is wanted, so they stay one-shot.
+ *
+ * Pure, so it's unit-testable; the dispatcher consumes it.
+ */
+const WARM_CAPABLE_AGENTS = new Set(['goose', 'qwen']);
+
+export function shouldUseWarmBackend(task: {
+  agent: string | null;
+  session_id: string | null;
+  chat_id: string | null;
+}): boolean {
+  if (!task.agent || !WARM_CAPABLE_AGENTS.has(task.agent)) return false;
+  return task.session_id != null && task.chat_id != null;
+}
+
+/**
+ * Map an ACP prompt `stopReason` to the backend's ok/fail contract (TurnResult.ok).
+ *
+ * ACP's `StopReason` union includes normal completions (`end_turn`, `max_tokens`,
+ * `max_turn_requests`) and abnormal ones (`refusal`, `cancelled`). Only the latter
+ * two read as a failed turn; everything else (including an undefined/absent reason,
+ * which we default to `end_turn`) is a successful completion. Pure so it's testable
+ * independently of the warm process.
+ */
+export function isTurnOkForStopReason(stopReason: string | null | undefined): boolean {
+  const reason = stopReason ?? 'end_turn';
+  return reason !== 'refusal' && reason !== 'cancelled';
+}

apps/coder/src/services/backends/warm-acp.ts

@@ -0,0 +1,389 @@
+/**
+ * v2.6 Phase 2 — WarmAcpBackend (goose, qwen).
+ *
+ * One persistent stdio process + ONE `ClientSideConnection` per (chat, agent),
+ * `initialize` + `session/new` done ONCE, reused across every turn — the warm
+ * analogue of the previous one-shot `acp-dispatch.ts` (which spawned/torn-down a
+ * fresh `goose acp` / `qwen --acp` per turn). Mirrors Paseo's `SpawnedACPProcess`.
+ *
+ * Implements the Phase 0 `AgentBackend` interface (same contract as
+ * `OpenCodeServerBackend`). Emits transport-agnostic `AgentEvent`s via the SHARED
+ * `mapSessionUpdate` (reused verbatim from the one-shot stack); the dispatcher maps
+ * those to WS frames + `persistExternalAgentTurn`, unchanged.
+ *
+ * Lifecycle decisions (design.md §2b / §10):
+ *   - **Child lifetime is the pool's, not a request's.** Spawned once; never tied
+ *     to a per-turn abort signal. Only the in-flight `prompt` gets `ctx.signal` —
+ *     abort = ACP `session/cancel`, NOT killing the child.
+ *   - **Per-turn abort** cancels the prompt on the warm connection so the SAME
+ *     process serves the next turn.
+ *   - **Crash** (child exit) marks `agent_sessions.status='crashed'` + logs; the
+ *     next `ensureSession` re-spawns + re-`session/new` (Phase 3 hardens auto-restart).
+ *   - **Resume across a process restart is NOT attempted in Phase 2.** goose ACP
+ *     advertises no `loadSession`/`session.resume`; qwen does, but cross-restart
+ *     resume is Phase 3. Within ONE live process the ACP session persists across
+ *     turns (the whole point of "warm"); a restart re-`session/new` (memory loss
+ *     across restart, accepted per §10). The agent's resume capabilities ARE
+ *     probed and logged for forward-compat.
+ *
+ * Each WarmAcpBackend instance owns exactly one (chat, agent) — the dispatcher
+ * pools them under `agentPool.register(chatId, agent, backend)`.
+ *
+ * SDK note (@agentclientprotocol/sdk@^0.22.1, cross-checked against the design's
+ * `^0.14` worry): the resume method is the STABLE `resumeSession` (`session/resume`,
+ * gated by `agentCapabilities.sessionCapabilities.resume`), NOT the `^0.14`
+ * `unstable_resumeSession`. `loadSession` is gated by `agentCapabilities.loadSession`.
+ */
+import { spawn, type ChildProcess } from 'node:child_process';
+import type { FastifyBaseLogger } from 'fastify';
+import { ClientSideConnection, type Client } from '@agentclientprotocol/sdk';
+import type { Sql } from '../../db.js';
+import { resolveLaunchSpec } from '../acp-spawn.js';
+import { isTurnOkForStopReason } from './warm-acp-routing.js';
+import { getResolvedRegistry, type ResolvedProviderDef } from '../provider-config-registry.js';
+import { createAcpNdJsonStream } from '../acp-stream.js';
+import { mapSessionUpdate } from '../acp-event-map.js';
+import { buildAcpClient } from '../acp-client.js';
+import { cancelPendingPermission } from '../permission-waiter.js';
+import { type AcpToolSnapshot, synthesizeCanceledSnapshots } from '../acp-tool-snapshot.js';
+import type {
+  AgentBackend,
+  AgentEvent,
+  AgentSessionHandle,
+  EnsureSessionOpts,
+  PromptCtx,
+  TurnResult,
+} from '../agent-backend.js';
+
+/** State for one in-flight turn (only one at a time per backend — turns serialize). */
+interface TurnState {
+  /** Per-turn task id, for routing permission prompts back to the UI. */
+  taskId: string | undefined;
+  /** BooCode session id for permission-waiter's broker frames. */
+  sessionId: string;
+  /** Per-turn mode id (autonomous-mode gate in permission-waiter). */
+  modeId: string | undefined;
+  onEvent: (e: AgentEvent) => void;
+  /** Tool-call snapshot accumulator for this turn — merge across tool_call_update. */
+  snapshots: Map<string, AcpToolSnapshot>;
+}
+
+export interface WarmAcpBackendDeps {
+  sql: Sql;
+  log: FastifyBaseLogger;
+  /** The (chat, agent) this backend serves — its pool identity + DB key. */
+  chatId: string;
+  agent: string;
+  /** Resolved binary for the agent (from available_agents.install_path), or null. */
+  installPath: string | null;
+  /** Optional override of the resolved registry def (defaults to a live lookup). */
+  resolved?: ResolvedProviderDef;
+}
+
+export class WarmAcpBackend implements AgentBackend {
+  readonly backend = 'acp_warm' as const;
+
+  private readonly sql: Sql;
+  private readonly log: FastifyBaseLogger;
+  private readonly chatId: string;
+  private readonly agent: string;
+  private readonly installPath: string | null;
+  private readonly resolvedOverride: ResolvedProviderDef | undefined;
+
+  private child: ChildProcess | null = null;
+  private connection: ClientSideConnection | null = null;
+  /** The single ACP session id for this warm process; null until session/new. */
+  private acpSessionId: string | null = null;
+  private up = false;
+  /** Idempotent spawn guard — one warm process per backend, started lazily. */
+  private starting: Promise<void> | null = null;
+  /** Resume capabilities probed at initialize, logged for forward-compat (Phase 3). */
+  private supportsLoadSession = false;
+  private supportsResumeSession = false;
+
+  /** The current in-flight turn; the Client closures read it. Null between turns. */
+  private activeTurn: TurnState | null = null;
+
+  constructor(deps: WarmAcpBackendDeps) {
+    this.sql = deps.sql;
+    this.log = deps.log;
+    this.chatId = deps.chatId;
+    this.agent = deps.agent;
+    this.installPath = deps.installPath;
+    this.resolvedOverride = deps.resolved;
+  }
+
+  /** §2: liveness for the health endpoint + dispatcher fallback decision. */
+  health(): 'up' | 'down' {
+    return this.up ? 'up' : 'down';
+  }
+
+  /** Phase 3: busy iff this backend's single session has an in-flight turn. The
+   *  pool reads this to skip idle/LRU eviction (never kill the child mid-prompt). */
+  isBusy(): boolean {
+    return this.activeTurn != null;
+  }
+
+  // ─── warm-process lifecycle (2.1 spawn + initialize + session/new ONCE) ───────
+
+  /** Lazy: spawn the warm process on first use. Idempotent — one process per backend. */
+  private ensureProcess(worktreePath: string): Promise<void> {
+    if (this.up && this.connection && this.acpSessionId) return Promise.resolve();
+    if (!this.starting) {
+      this.starting = this.startProcess(worktreePath).catch((err) => {
+        // Reset so a later ensureSession can retry the spawn after a failed start.
+        this.starting = null;
+        throw err;
+      });
+    }
+    return this.starting;
+  }
+
+  private async startProcess(worktreePath: string): Promise<void> {
+    const resolved = this.resolvedOverride ?? getResolvedRegistry().get(this.agent);
+    const spec = resolved ? resolveLaunchSpec(resolved, this.installPath) : null;
+    if (!spec) throw new Error(`warm-acp: agent '${this.agent}' does not support ACP (no launch spec)`);
+
+    this.log.info({ agent: this.agent, chatId: this.chatId, binary: spec.binary, worktreePath }, 'warm-acp: spawning warm process');
+    // Child lifetime is the pool's. NOT tied to any per-turn abort signal — only
+    // the in-flight prompt is cancellable (via ACP session/cancel in prompt()).
+    const child = spawn(spec.binary, spec.args, {
+      cwd: worktreePath,
+      stdio: ['pipe', 'pipe', 'pipe'],
+      env: { ...process.env, ...spec.env },
+    });
+    this.child = child;
+
+    // 2.3: supervise the child; react to its exit, never let a request scope kill it.
+    child.on('exit', (code, signal) => {
+      this.up = false;
+      this.connection = null;
+      this.acpSessionId = null;
+      this.starting = null;
+      this.log.warn({ agent: this.agent, chatId: this.chatId, code, signal }, 'warm-acp: warm process exited — marking crashed (rebuild on next turn)');
+      void this.markCrashed();
+    });
+    // A spawn error (e.g. ENOENT) surfaces here, not as an exit.
+    child.on('error', (err) => {
+      this.up = false;
+      this.log.error({ agent: this.agent, chatId: this.chatId, err: errMsg(err) }, 'warm-acp: warm process error');
+    });
+
+    const stream = createAcpNdJsonStream(child);
+    const connection = new ClientSideConnection(() => this.buildClient(worktreePath), stream);
+
+    const init = await connection.initialize({
+      protocolVersion: 1,
+      clientInfo: { name: 'boocoder', version: '2.6.0' },
+      clientCapabilities: {},
+    });
+    const caps = init.agentCapabilities;
+    this.supportsLoadSession = caps?.loadSession === true;
+    this.supportsResumeSession = caps?.sessionCapabilities?.resume != null;
+
+    const session = await connection.newSession({ cwd: worktreePath, mcpServers: [] });
+    this.connection = connection;
+    this.acpSessionId = session.sessionId;
+    this.up = true;
+    this.log.info(
+      {
+        agent: this.agent,
+        chatId: this.chatId,
+        acpSessionId: session.sessionId,
+        loadSession: this.supportsLoadSession,
+        resumeSession: this.supportsResumeSession,
+      },
+      'warm-acp: warm session ready',
+    );
+  }
+
+  /** Build the ACP Client callbacks ONCE per connection (shared `buildAcpClient`).
+   *  `resolveTurn` reads `this.activeTurn` at each callback so events/permissions
+   *  route to the live turn — exactly the prior behavior. The warm session always
+   *  has a non-empty `sessionId`, so the shared `taskId && sessionId` permission
+   *  gate is equivalent to the old `turn?.taskId` gate. */
+  private buildClient(worktreePath: string): Client {
+    return buildAcpClient(worktreePath, () => {
+      const turn = this.activeTurn;
+      if (!turn) return null;
+      return {
+        taskId: turn.taskId,
+        sessionId: turn.sessionId,
+        modeId: turn.modeId,
+        agent: this.agent,
+        onSessionUpdate: (params) => {
+          for (const event of mapSessionUpdate(params, turn.snapshots)) turn.onEvent(event);
+        },
+      };
+    });
+  }
+
+  // ─── ensureSession: create-or-reuse the warm session (2.1) ───────────────────
+
+  async ensureSession(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle> {
+    await this.ensureProcess(opts.worktreePath);
+    if (!this.acpSessionId) throw new Error('warm-acp: session not ready after ensureProcess');
+
+    // P1.5-b: agent_sessions keys on (chat_id, agent). The ACP session id is the
+    // resume handle WITHIN the live process; across a process restart it's stale,
+    // so ensureProcess re-`session/new` and we upsert the fresh id here.
+    await this.sql`
+      INSERT INTO agent_sessions
+        (chat_id, session_id, worktree_id, agent, backend, agent_session_id, server_port, status, last_active_at)
+      VALUES
+        (${opts.chatId}, ${sessionId}, ${opts.worktreeId}, ${opts.agent}, 'acp_warm', ${this.acpSessionId}, NULL, 'active', clock_timestamp())
+      ON CONFLICT (chat_id, agent) DO UPDATE SET
+        session_id = EXCLUDED.session_id,
+        worktree_id = EXCLUDED.worktree_id,
+        backend = 'acp_warm',
+        agent_session_id = EXCLUDED.agent_session_id,
+        server_port = NULL,
+        status = 'active',
+        last_active_at = clock_timestamp()
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: opts.chatId, agent: opts.agent }, 'warm-acp: agent_sessions upsert failed (non-fatal)');
+    });
+
+    return {
+      sessionId,
+      agent: opts.agent,
+      backend: 'acp_warm',
+      chatId: opts.chatId,
+      worktreeId: opts.worktreeId,
+      agentSessionId: this.acpSessionId,
+      serverPort: null,
+    };
+  }
+
+  // ─── prompt: one turn on the warm connection (2.2) ───────────────────────────
+
+  async prompt(handle: AgentSessionHandle, input: string, ctx: PromptCtx): Promise<TurnResult> {
+    // The warm process may have crashed between ensureSession and here, or this
+    // backend was rebuilt — re-establish before prompting.
+    await this.ensureProcess(ctx.worktreePath);
+    const connection = this.connection;
+    const acpSessionId = this.acpSessionId;
+    if (!connection || !acpSessionId) {
+      return { ok: false, error: 'warm-acp: no live ACP connection' };
+    }
+
+    // v2.7 busy-assert: one in-flight turn per warm session. The dispatcher
+    // serializes turns per (chat, agent), so this never fires in normal dispatch —
+    // but a second concurrent prompt would silently overwrite `activeTurn` and
+    // orphan the first turn, so reject instead.
+    if (this.activeTurn) {
+      return { ok: false, error: 'warm-acp: session already has an in-flight turn' };
+    }
+
+    const snapshots = new Map<string, AcpToolSnapshot>();
+    // taskId routes permission/elicitation prompts back to the UI. The dispatcher
+    // passes it (plus mode) on the per-turn PromptCtx; permission-waiter keys on it.
+    const turn: TurnState = {
+      taskId: ctx.taskId,
+      sessionId: handle.sessionId,
+      modeId: ctx.modeId,
+      onEvent: ctx.onEvent,
+      snapshots,
+    };
+    this.activeTurn = turn;
+
+    // Per-turn abort: cancel the in-flight prompt on the SAME connection — never
+    // kill the child (that's the pool's lifetime). On cancel we also synthesize
+    // 'canceled' updates for any still-running tool calls so the UI doesn't leave
+    // them spinning (mirrors AcpStreamContext.markAborted).
+    let aborted = false;
+    const onAbort = () => {
+      if (aborted) return;
+      aborted = true;
+      connection.cancel({ sessionId: acpSessionId }).catch(() => {});
+      if (ctx.taskId) cancelPendingPermission(ctx.taskId);
+      for (const snap of synthesizeCanceledSnapshots(snapshots.values())) {
+        snapshots.set(snap.toolCallId, snap);
+        ctx.onEvent({ type: 'tool_update', toolCall: snap });
+      }
+    };
+
+    if (ctx.signal.aborted) {
+      this.activeTurn = null;
+      return { ok: false, error: 'aborted' };
+    }
+    ctx.signal.addEventListener('abort', onAbort, { once: true });
+
+    try {
+      const result = await connection.prompt({
+        sessionId: acpSessionId,
+        prompt: [{ type: 'text', text: input }],
+      });
+      if (aborted) return { ok: false, error: 'aborted' };
+      const stopReason = result.stopReason ?? 'end_turn';
+      return isTurnOkForStopReason(stopReason)
+        ? { ok: true }
+        : { ok: false, error: `stop_reason: ${stopReason}` };
+    } catch (err) {
+      if (aborted) return { ok: false, error: 'aborted' };
+      return { ok: false, error: errMsg(err) };
+    } finally {
+      ctx.signal.removeEventListener('abort', onAbort);
+      this.activeTurn = null;
+      await this.sql`
+        UPDATE agent_sessions SET status = 'idle', last_active_at = clock_timestamp()
+        WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+      `.catch(() => {});
+    }
+  }
+
+  // ─── teardown ────────────────────────────────────────────────────────────────
+
+  async closeSession(handle: AgentSessionHandle): Promise<void> {
+    // Gracefully close the ACP session if the agent supports it; then kill the child.
+    if (this.connection && this.acpSessionId) {
+      await this.connection.closeSession({ sessionId: this.acpSessionId }).catch(() => {});
+    }
+    await this.killChild();
+    await this.sql`
+      UPDATE agent_sessions SET status = 'closed'
+      WHERE chat_id = ${handle.chatId} AND agent = ${handle.agent}
+    `.catch(() => {});
+  }
+
+  async dispose(): Promise<void> {
+    this.up = false;
+    this.activeTurn = null;
+    if (this.connection && this.acpSessionId) {
+      await this.connection.closeSession({ sessionId: this.acpSessionId }).catch(() => {});
+    }
+    await this.killChild();
+    this.connection = null;
+    this.acpSessionId = null;
+    this.starting = null;
+  }
+
+  private async killChild(): Promise<void> {
+    const child = this.child;
+    this.child = null;
+    if (!child || child.killed) return;
+    child.kill('SIGTERM');
+    await new Promise<void>((resolve) => {
+      const t = setTimeout(() => {
+        if (!child.killed) child.kill('SIGKILL');
+        resolve();
+      }, 5_000);
+      t.unref?.();
+      child.once('close', () => {
+        clearTimeout(t);
+        resolve();
+      });
+    });
+  }
+
+  private async markCrashed(): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions SET status = 'crashed'
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch(() => {});
+  }
+}
+
+function errMsg(e: unknown): string {
+  return e instanceof Error ? e.message : String(e);
+}

apps/coder/src/services/cancel-registry.ts

@@ -0,0 +1,50 @@
+/**
+ * F1 — per-task abort registry. A Stop on an external-agent task must reach the
+ * in-flight run and abort its child / prompt. Each external run-function registers
+ * its per-turn AbortController here keyed by task id; the cancel route calls
+ * `cancel(taskId)` to fire it; the run-function's `.finally` deletes the entry.
+ *
+ * Idempotent by construction:
+ *   - `cancel()` on an already-aborted controller no-ops (AbortController.abort()
+ *     is idempotent) → a rapid double-Stop is safe.
+ *   - `cancel()` on an unknown / already-finished task returns false → a
+ *     cancel-after-natural-exit (entry already deleted) and a Stop on a native
+ *     boocode task (never registered) are both safe no-ops.
+ *
+ * Pure (no DB / child / IO) so the abort wiring + idempotency contract is
+ * unit-testable in isolation — mirrors the turn-guard / lifecycle-decisions
+ * pure-helper precedent.
+ */
+export interface CancelRegistry {
+  /** Create + store an AbortController for this task, returning it for the run. */
+  register(taskId: string): AbortController;
+  /** Abort the task's in-flight run. Returns false when no controller is registered. */
+  cancel(taskId: string): boolean;
+  /** Drop the task's entry (called from the run's `.finally`). No-op if absent. */
+  delete(taskId: string): void;
+  /** Whether a controller is currently registered for this task. */
+  has(taskId: string): boolean;
+}
+
+export function createCancelRegistry(): CancelRegistry {
+  const controllers = new Map<string, AbortController>();
+  return {
+    register(taskId) {
+      const ac = new AbortController();
+      controllers.set(taskId, ac);
+      return ac;
+    },
+    cancel(taskId) {
+      const ac = controllers.get(taskId);
+      if (!ac) return false;
+      ac.abort();
+      return true;
+    },
+    delete(taskId) {
+      controllers.delete(taskId);
+    },
+    has(taskId) {
+      return controllers.has(taskId);
+    },
+  };
+}

apps/coder/src/services/checkpoints.ts

@@ -0,0 +1,306 @@
+/**
+ * write-edit-robustness #4 — worktree checkpoints.
+ *
+ * External agents (opencode / goose / qwen / claude) write DIRECTLY into the
+ * shared session worktree (`/tmp/booworktrees/sess-<id>`); BooCode's own `rewind`
+ * only reverses `pending_changes` against the project root, so it has zero coverage
+ * there. A checkpoint is a pre-turn shadow-commit of the worktree tree (tracked +
+ * untracked) captured WITHOUT touching the real index/working tree, stored in a
+ * private GC-safe ref. `restoreCheckpoint` rewinds the worktree to that commit,
+ * trims the transcript from the anchor message forward, and resets the agent
+ * backend so the next turn re-establishes a fresh context consistent with the
+ * restored files.
+ *
+ * All git goes through hostExec + shellEscape (BooCoder runs on the host; the
+ * worktrees live on the host fs). Checkpoint CREATION is best-effort: a failure
+ * logs and returns null — it must NEVER throw into the dispatch turn.
+ */
+import { randomUUID } from 'node:crypto';
+import type { FastifyBaseLogger } from 'fastify';
+import type { Sql } from '../db.js';
+import { hostExec } from './host-exec.js';
+import { agentPool, OPENCODE_POOL_KEY } from './agent-pool.js';
+import type { AgentSessionHandle } from './agent-backend.js';
+
+/** Minimal shell escape for paths/refs (single-quote wrapping). Mirrors worktrees.ts. */
+function shellEscape(s: string): string {
+  return "'" + s.replace(/'/g, "'\\''") + "'";
+}
+
+/**
+ * Pure builder for the shadow-commit command. Captures tracked + untracked files
+ * in the worktree into a temp index (so the real index/working tree is untouched),
+ * writes a tree, commits it parented on HEAD, and parks the commit under a private
+ * ref `refs/boocode/checkpoints/<id>` so git's GC never reclaims it. Prints ONLY
+ * the resulting SHA on stdout (the trailing `printf '%s'`), so the caller parses
+ * stdout.trim() directly.
+ *
+ * `id` is the row UUID (minted before the ref so the ref name matches the row).
+ * Both the worktree path and the id are shell-escaped.
+ */
+export function buildShadowCommitCommand(worktreePath: string, id: string): string {
+  const wt = shellEscape(worktreePath);
+  const ref = shellEscape(`refs/boocode/checkpoints/${id}`);
+  return (
+    `cd ${wt} && TMP=$(mktemp) && GIT_INDEX_FILE="$TMP" git read-tree HEAD ` +
+    `&& GIT_INDEX_FILE="$TMP" git add -A ` +
+    `&& TREE=$(GIT_INDEX_FILE="$TMP" git write-tree) ` +
+    `&& SHA=$(git commit-tree "$TREE" -p HEAD -m "boocode checkpoint") ` +
+    `&& git update-ref ${ref} "$SHA" && rm -f "$TMP" && printf '%s' "$SHA"`
+  );
+}
+
+export interface CreateCheckpointArgs {
+  chatId: string;
+  sessionId: string | null;
+  worktreeId: string | null;
+  worktreePath: string;
+  messageId: string | null;
+  label?: string | null;
+}
+
+/**
+ * Capture a pre-turn checkpoint of the session worktree. Best-effort: returns the
+ * inserted row's { id, commit_sha } on success, or null on any failure (the turn
+ * proceeds either way — a missing checkpoint just means no restore point for that
+ * turn). NEVER throws.
+ *
+ * The id is minted up front so the git ref name (`refs/boocode/checkpoints/<id>`)
+ * matches the DB row id, keeping ref and row in lockstep.
+ */
+export async function createCheckpoint(
+  sql: Sql,
+  args: CreateCheckpointArgs,
+  opts?: { signal?: AbortSignal; log?: FastifyBaseLogger },
+): Promise<{ id: string; commit_sha: string } | null> {
+  const id = randomUUID();
+  try {
+    const cmd = buildShadowCommitCommand(args.worktreePath, id);
+    const res = await hostExec(cmd, { signal: opts?.signal, timeoutMs: 30_000 });
+    if (res.exitCode !== 0) {
+      opts?.log?.warn(
+        { chatId: args.chatId, worktreePath: args.worktreePath, stderr: res.stderr.trim().slice(0, 500) },
+        'checkpoint: shadow-commit failed (turn proceeds without a checkpoint)',
+      );
+      return null;
+    }
+    const commitSha = res.stdout.trim();
+    if (!commitSha) {
+      opts?.log?.warn(
+        { chatId: args.chatId, worktreePath: args.worktreePath },
+        'checkpoint: shadow-commit produced no SHA (turn proceeds)',
+      );
+      return null;
+    }
+
+    await sql`
+      INSERT INTO checkpoints (id, chat_id, session_id, worktree_id, message_id, commit_sha, label)
+      VALUES (${id}, ${args.chatId}, ${args.sessionId}, ${args.worktreeId}, ${args.messageId}, ${commitSha}, ${args.label ?? null})
+    `;
+    opts?.log?.info({ checkpointId: id, chatId: args.chatId, commitSha }, 'checkpoint: created');
+    return { id, commit_sha: commitSha };
+  } catch (err) {
+    opts?.log?.warn(
+      { chatId: args.chatId, err: err instanceof Error ? err.message : String(err) },
+      'checkpoint: create threw (turn proceeds without a checkpoint)',
+    );
+    return null;
+  }
+}
+
+/** Error the route maps to a 404 when the checkpoint can't be resolved / scoped. */
+export class CheckpointNotFoundError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = 'CheckpointNotFoundError';
+  }
+}
+
+export interface RestoreCheckpointResult {
+  checkpoint_id: string;
+  messages_deleted: number;
+  worktree_reset: boolean;
+  backend_reset: boolean;
+}
+
+export interface RestoreCheckpointOpts {
+  signal?: AbortSignal;
+  log?: FastifyBaseLogger;
+  /** If set, the checkpoint MUST belong to this session (route scope guard). */
+  sessionId?: string;
+}
+
+interface CheckpointRow {
+  id: string;
+  chat_id: string;
+  session_id: string | null;
+  worktree_id: string | null;
+  message_id: string | null;
+  commit_sha: string;
+  created_at: Date;
+}
+
+/**
+ * Restore a checkpoint: rewind its worktree to the shadow commit, trim the
+ * transcript from the anchor message forward, reset the backend session, and drop
+ * now-orphaned later checkpoints. Throws CheckpointNotFoundError when the
+ * checkpoint is missing or not in the requested session (route → 404).
+ */
+export async function restoreCheckpoint(
+  sql: Sql,
+  checkpointId: string,
+  opts?: RestoreCheckpointOpts,
+): Promise<RestoreCheckpointResult> {
+  // 1. Resolve the checkpoint.
+  const [cp] = await sql<CheckpointRow[]>`
+    SELECT id, chat_id, session_id, worktree_id, message_id, commit_sha, created_at
+    FROM checkpoints WHERE id = ${checkpointId}
+  `;
+  if (!cp) {
+    throw new CheckpointNotFoundError('checkpoint not found');
+  }
+  // Authorization scope (fail-safe): the checkpoint's chat must belong to the
+  // requested session. cp.session_id is a denormalized hint that may be null, so
+  // gating on it directly fails open — resolve the owning session via chats
+  // (authoritative; chat_id is NOT NULL) and deny on any mismatch or missing row.
+  if (opts?.sessionId) {
+    const [owner] = await sql<{ session_id: string | null }[]>`
+      SELECT session_id FROM chats WHERE id = ${cp.chat_id}
+    `;
+    if (!owner || owner.session_id !== opts.sessionId) {
+      throw new CheckpointNotFoundError('checkpoint not in session');
+    }
+  }
+
+  // 2. Resolve the worktree path (by worktree_id, else the session's active one).
+  let worktreePath: string | null = null;
+  if (cp.worktree_id) {
+    const [wt] = await sql<{ path: string }[]>`
+      SELECT path FROM worktrees WHERE id = ${cp.worktree_id}
+    `;
+    worktreePath = wt?.path ?? null;
+  }
+  if (!worktreePath) {
+    const sid = cp.session_id ?? opts?.sessionId ?? null;
+    if (sid) {
+      const [wt] = await sql<{ path: string }[]>`
+        SELECT path FROM worktrees WHERE session_id = ${sid} AND status = 'active' LIMIT 1
+      `;
+      worktreePath = wt?.path ?? null;
+    }
+  }
+
+  // 3. Worktree reset — hard-reset to the shadow commit, then clean untracked.
+  let worktreeReset = false;
+  if (worktreePath) {
+    const resetRes = await hostExec(
+      `git -C ${shellEscape(worktreePath)} reset --hard ${shellEscape(cp.commit_sha)}`,
+      { signal: opts?.signal, timeoutMs: 30_000 },
+    ).catch((err) => {
+      opts?.log?.warn(
+        { checkpointId, err: err instanceof Error ? err.message : String(err) },
+        'checkpoint restore: reset --hard threw',
+      );
+      return null;
+    });
+    if (resetRes && resetRes.exitCode === 0) {
+      const cleanRes = await hostExec(
+        `git -C ${shellEscape(worktreePath)} clean -fd`,
+        { signal: opts?.signal, timeoutMs: 30_000 },
+      ).catch(() => null);
+      worktreeReset = cleanRes != null && cleanRes.exitCode === 0;
+      if (!worktreeReset) {
+        opts?.log?.warn({ checkpointId, worktreePath }, 'checkpoint restore: clean -fd did not succeed');
+      }
+    } else {
+      opts?.log?.warn(
+        { checkpointId, worktreePath, stderr: resetRes?.stderr?.trim()?.slice(0, 500) },
+        'checkpoint restore: reset --hard did not succeed',
+      );
+    }
+  } else {
+    opts?.log?.warn({ checkpointId }, 'checkpoint restore: no worktree path resolved (files not reset)');
+  }
+
+  // 4. Trim the transcript from the anchor message forward. message_parts FK to
+  //    messages is ON DELETE CASCADE (apps/server schema.sql:49), so parts are
+  //    removed with their messages — no explicit parts delete needed.
+  let messagesDeleted = 0;
+  if (cp.message_id) {
+    const deleted = await sql<{ id: string }[]>`
+      DELETE FROM messages
+      WHERE chat_id = ${cp.chat_id}
+        AND created_at >= (SELECT created_at FROM messages WHERE id = ${cp.message_id})
+      RETURNING id
+    `;
+    messagesDeleted = deleted.length;
+  }
+
+  // 5. Backend reset — mark the chat's agent sessions crashed so the next turn
+  //    re-establishes a fresh backend, and evict the live pool session(s) for this
+  //    (chat, agent). Warm backends hold context server-side with no partial
+  //    rewind, so a full reset is the only consistent option (proposal §4).
+  const agentRows = await sql<{ agent: string; backend: string; agent_session_id: string | null; session_id: string | null; worktree_id: string | null }[]>`
+    SELECT agent, backend, agent_session_id, session_id, worktree_id
+    FROM agent_sessions WHERE chat_id = ${cp.chat_id}
+  `;
+  await sql`
+    UPDATE agent_sessions SET status = 'crashed' WHERE chat_id = ${cp.chat_id}
+  `.catch(() => {});
+
+  let backendReset = false;
+  try {
+    // opencode runs on the SHARED server (keyed on a sentinel, not the chat) — close
+    // just this chat's session(s) on it, mirroring the lifecycle close-hook.
+    const ocBackend = agentPool.peek(OPENCODE_POOL_KEY, 'opencode');
+    if (ocBackend) {
+      for (const row of agentRows) {
+        if (row.backend !== 'opencode_server' || !row.agent_session_id) continue;
+        const handle: AgentSessionHandle = {
+          sessionId: row.session_id ?? '',
+          agent: row.agent,
+          backend: 'opencode_server',
+          chatId: cp.chat_id,
+          worktreeId: row.worktree_id ?? '',
+          agentSessionId: row.agent_session_id,
+          serverPort: null,
+        };
+        await ocBackend.closeSession(handle).catch((err) => {
+          opts?.log?.warn(
+            { checkpointId, err: err instanceof Error ? err.message : String(err) },
+            'checkpoint restore: opencode closeSession threw',
+          );
+        });
+      }
+    }
+    // Warm-ACP backends are pooled under the chat id — dispose them (kills the
+    // goose/qwen child). closeChat skips busy backends (a live turn isn't torn down).
+    const disposed = await agentPool.closeChat(cp.chat_id);
+    backendReset = true;
+    opts?.log?.info({ checkpointId, chatId: cp.chat_id, disposed }, 'checkpoint restore: backend reset');
+  } catch (err) {
+    opts?.log?.warn(
+      { checkpointId, err: err instanceof Error ? err.message : String(err) },
+      'checkpoint restore: backend reset threw',
+    );
+  }
+
+  // 6. Drop now-orphaned later checkpoints for this chat (their anchor messages were
+  //    just trimmed). Compare `created_at` SERVER-SIDE via a subquery (NOT the JS
+  //    Date round-trip, which truncates the stored microsecond precision to ms and
+  //    would make this checkpoint delete ITSELF), and exclude this checkpoint's own
+  //    id so it always survives — letting the user re-restore to it.
+  await sql`
+    DELETE FROM checkpoints
+    WHERE chat_id = ${cp.chat_id}
+      AND id <> ${cp.id}
+      AND created_at > (SELECT created_at FROM checkpoints WHERE id = ${cp.id})
+  `.catch(() => {});
+
+  return {
+    checkpoint_id: checkpointId,
+    messages_deleted: messagesDeleted,
+    worktree_reset: worktreeReset,
+    backend_reset: backendReset,
+  };
+}

apps/coder/src/services/claude-command-discovery.ts

@@ -0,0 +1,108 @@
+/**
+ * v2.5.11: discover Claude Code's real, enabled commands + plugin skills from
+ * disk so the coder slash menu shows them (claude is PTY — no ACP discovery).
+ *
+ * Scope (v1): user-global only — `~/.claude/commands/*.md` plus the enabled
+ * plugins listed in `~/.claude/settings.json:enabledPlugins` (user-scope install
+ * paths from `~/.claude/plugins/.../installed_plugins.json`). Project-local
+ * plugins and `<cwd>/.claude/commands` are deferred. Names are bare.
+ */
+import { readFileSync, readdirSync, existsSync } from 'node:fs';
+import { homedir } from 'node:os';
+import { join } from 'node:path';
+import type { AgentCommand } from './provider-types.js';
+
+/** Minimal frontmatter reader — single-line `key: value` between `---` fences. */
+function frontmatterField(content: string, field: string): string | undefined {
+  const block = content.match(/^---\r?\n([\s\S]*?)\r?\n---/);
+  if (!block?.[1]) return undefined;
+  const m = block[1].match(new RegExp(`^${field}:\\s*(.+)$`, 'm'));
+  return m?.[1]?.trim().replace(/^["']|["']$/g, '') || undefined;
+}
+
+function readCommandDir(dir: string): AgentCommand[] {
+  if (!existsSync(dir)) return [];
+  let files: string[];
+  try {
+    files = readdirSync(dir);
+  } catch {
+    return [];
+  }
+  const out: AgentCommand[] = [];
+  for (const f of files) {
+    if (!f.endsWith('.md')) continue;
+    let description: string | undefined;
+    try {
+      description = frontmatterField(readFileSync(join(dir, f), 'utf8'), 'description');
+    } catch {
+      /* unreadable — still list the command by name */
+    }
+    out.push({ name: f.slice(0, -3), kind: 'command', ...(description ? { description } : {}) });
+  }
+  return out;
+}
+
+function readSkillDir(dir: string): AgentCommand[] {
+  if (!existsSync(dir)) return [];
+  let entries: string[];
+  try {
+    entries = readdirSync(dir);
+  } catch {
+    return [];
+  }
+  const out: AgentCommand[] = [];
+  for (const sub of entries) {
+    const skillMd = join(dir, sub, 'SKILL.md');
+    if (!existsSync(skillMd)) continue;
+    let content: string;
+    try {
+      content = readFileSync(skillMd, 'utf8');
+    } catch {
+      continue;
+    }
+    out.push({
+      name: frontmatterField(content, 'name') ?? sub,
+      kind: 'skill',
+      ...(() => {
+        const d = frontmatterField(content, 'description');
+        return d ? { description: d } : {};
+      })(),
+    });
+  }
+  return out;
+}
+
+export function discoverClaudeCommands(): AgentCommand[] {
+  const root = join(homedir(), '.claude');
+  const out: AgentCommand[] = [];
+
+  // User custom commands.
+  out.push(...readCommandDir(join(root, 'commands')));
+
+  // Enabled plugins (user-scope installs).
+  try {
+    const settings = JSON.parse(readFileSync(join(root, 'settings.json'), 'utf8')) as {
+      enabledPlugins?: Record<string, boolean>;
+    };
+    const installed = JSON.parse(
+      readFileSync(join(root, 'plugins', 'installed_plugins.json'), 'utf8'),
+    ) as { plugins?: Record<string, Array<{ scope?: string; installPath?: string }>> };
+
+    const enabled = settings.enabledPlugins ?? {};
+    const plugins = installed.plugins ?? {};
+    for (const [key, on] of Object.entries(enabled)) {
+      if (!on) continue;
+      const installs = plugins[key] ?? [];
+      const installPath = (installs.find((i) => i.scope === 'user') ?? installs[0])?.installPath;
+      if (!installPath || !existsSync(installPath)) continue;
+      out.push(...readSkillDir(join(installPath, 'skills')));
+      out.push(...readCommandDir(join(installPath, 'commands')));
+    }
+  } catch {
+    /* missing/unreadable plugin config → user commands only */
+  }
+
+  // Dedupe by name (first wins).
+  const seen = new Set<string>();
+  return out.filter((c) => (seen.has(c.name) ? false : (seen.add(c.name), true)));
+}

apps/coder/src/services/command-availability.ts

@@ -0,0 +1,22 @@
+/**
+ * v2.3 phase 2: tier-1 fast availability check — is a binary on PATH?
+ *
+ * Uses execFile (NO shell) because the binary name can come from the provider
+ * config file (custom ACP entries) — mirrors the Phase 1 agent-probe hardening.
+ * Note: agent-probe's `whichBinary` returns the resolved path (it needs it for
+ * `install_path`); this returns a boolean. Kept separate rather than over-
+ * refactored into one helper — different return contracts, two short call sites.
+ */
+import { execFile as execFileCb } from 'node:child_process';
+import { promisify } from 'node:util';
+
+const execFile = promisify(execFileCb);
+
+export async function isCommandAvailable(binary: string): Promise<boolean> {
+  try {
+    const { stdout } = await execFile('which', [binary], { timeout: 10_000 });
+    return stdout.trim().length > 0;
+  } catch {
+    return false;
+  }
+}

apps/coder/src/services/cursor-models.ts

@@ -1,39 +0,0 @@
-/**
- * Cursor model list parser — lifted from Paseo cursor-acp-agent.ts
- */
-import type { ProviderModel } from './provider-types.js';
-
-const CURSOR_MODEL_MARKER_PATTERN = /\s+\((?:default|current)\)$/;
-
-export function parseCursorAgentModelsOutput(output: string): ProviderModel[] {
-  const parsed = output
-    .split(/\r?\n/)
-    .map((line) => line.trim())
-    .filter((line) => line && line !== 'Available models' && !line.startsWith('Tip:'))
-    .map((line) => {
-      const separatorIndex = line.indexOf(' - ');
-      if (separatorIndex <= 0) return null;
-
-      const id = line.slice(0, separatorIndex).trim();
-      const rawLabel = line.slice(separatorIndex + 3).trim();
-      if (!id || !rawLabel) return null;
-
-      let marker: 'default' | 'current' | null = null;
-      if (rawLabel.endsWith(' (default)')) marker = 'default';
-      else if (rawLabel.endsWith(' (current)')) marker = 'current';
-
-      return { id, label: rawLabel.replace(CURSOR_MODEL_MARKER_PATTERN, ''), marker };
-    })
-    .filter((m): m is { id: string; label: string; marker: 'default' | 'current' | null } => m !== null);
-
-  const defaultModelId =
-    parsed.find((m) => m.marker === 'default')?.id ??
-    parsed.find((m) => m.marker === 'current')?.id ??
-    parsed[0]?.id;
-
-  return parsed.map((model) => ({
-    id: model.id,
-    label: model.label,
-    isDefault: model.id === defaultModelId,
-  }));
-}

apps/coder/src/services/dcp-strip.ts

@@ -0,0 +1,77 @@
+/**
+ * Strip opencode-dcp plugin tags (`<dcp-message-id>mNNNN</dcp-message-id>`) that
+ * the @tarquinen/opencode-dcp plugin appends to assistant text and which
+ * otherwise render as literal text in the UI.
+ *
+ * Why a streaming stripper and not a per-chunk `.replace()`: opencode streams
+ * assistant text token-by-token, so the tag arrives SPLIT across many SSE deltas
+ * (`<dcp`, `-message`, `-id>`, `m0019`, `</dcp`, …). A per-chunk regex never sees
+ * a complete tag in any single fragment, so the fragments pass through and the
+ * dispatcher reassembles the full tag in the persisted/displayed content. The
+ * stripper below buffers across chunks: it emits everything that cannot be part
+ * of a forming tag and holds back only a trailing partial-tag prefix until the
+ * next chunk resolves it — without holding back legitimate `<…>` content.
+ */
+
+const DCP_TAG_RE = /<dcp-message-id>[^<]*<\/dcp-message-id>/g;
+const OPEN = '<dcp-message-id>';
+const CLOSE = '</dcp-message-id>';
+
+/** One-shot strip of COMPLETE tags. Safe for non-streaming / final content. */
+export function stripDcpTags(s: string): string {
+  return s.replace(DCP_TAG_RE, '');
+}
+
+/**
+ * Could `tail` (a substring starting at a `<`) still grow into a complete dcp
+ * tag on a future chunk? If so the caller must hold it back rather than emit it.
+ * Returns false for unrelated `<` content (`<div>`, `<T>`, …) so those stream
+ * normally.
+ */
+function isPartialDcp(tail: string): boolean {
+  // A prefix of the opening marker: '<', '<d', …, '<dcp-message-id'.
+  if (OPEN.startsWith(tail)) return true;
+  // Opening marker fully seen — content (and maybe a forming close) still streaming.
+  if (tail.startsWith(OPEN)) {
+    const rest = tail.slice(OPEN.length);
+    const lt = rest.indexOf('<');
+    if (lt === -1) return true; // still inside the [^<]* content run
+    return CLOSE.startsWith(rest.slice(lt)); // a partial close marker forming
+  }
+  return false;
+}
+
+export interface DcpStreamStripper {
+  /** Feed one text chunk; returns the portion safe to emit now (may be ''). */
+  push(chunk: string): string;
+  /** Stream end: returns whatever was held back, with complete tags stripped. */
+  flush(): string;
+}
+
+/** Stateful, cross-chunk-safe dcp stripper. One instance per turn. */
+export function makeDcpStreamStripper(): DcpStreamStripper {
+  let buf = '';
+  return {
+    push(chunk: string): string {
+      buf += chunk;
+      buf = buf.replace(DCP_TAG_RE, ''); // drop any now-complete tags
+      // Find the earliest `<` whose suffix is a forming dcp tag; hold from there,
+      // emit everything before it (real text, including unrelated `<…>`).
+      for (let i = buf.indexOf('<'); i !== -1; i = buf.indexOf('<', i + 1)) {
+        if (isPartialDcp(buf.slice(i))) {
+          const emit = buf.slice(0, i);
+          buf = buf.slice(i);
+          return emit;
+        }
+      }
+      const emit = buf;
+      buf = '';
+      return emit;
+    },
+    flush(): string {
+      const out = stripDcpTags(buf);
+      buf = '';
+      return out;
+    },
+  };
+}

apps/coder/src/services/finalize-message.ts

@@ -0,0 +1,76 @@
+import type { Sql } from '../db.js';
+import type { WsFrame } from '@boocode/contracts/ws-frames';
+
+export type TerminalMessageStatus = 'cancelled' | 'failed';
+
+/**
+ * F1 (D-7) — decide the terminal status a Stop'd / errored external turn lands in.
+ *
+ * A user Stop (the per-task AbortController fired) or a thrown `AbortError` is a
+ * deliberate, non-error outcome → `'cancelled'`. A genuine thrown error → `'failed'`.
+ * Keeping the two distinct keeps the human-inbox / failure surfaces honest.
+ *
+ * Pure (no DB / IO) so the mapping is unit-testable in isolation.
+ */
+export function classifyTerminalStatus(opts: { aborted: boolean; error?: unknown }): TerminalMessageStatus {
+  if (opts.aborted) return 'cancelled';
+  if (opts.error instanceof Error && opts.error.name === 'AbortError') return 'cancelled';
+  return 'failed';
+}
+
+/**
+ * F1 (OCE-001 / OCE-002) — finalize a streaming assistant message into a terminal
+ * state and publish the matching `message_complete` frame.
+ *
+ * Idempotent via `WHERE status = 'streaming'`: a second call (a double-Stop, or an
+ * abort short-circuit followed by the catch block) updates zero rows and does NOT
+ * re-publish, so the frontend reducer settles the message exactly once. It also
+ * never clobbers a row that already finished cleanly (`complete`) — the abort that
+ * raced a clean finish is a no-op.
+ *
+ * Returns `true` iff this call performed the finalization (the row was still
+ * streaming); `false` if it was already terminal or the id is absent (the throw
+ * preceded the row's creation).
+ */
+export async function finalizeStreamingMessage(
+  sql: Sql,
+  publishFrame: (sessionId: string, frame: WsFrame) => void,
+  opts: {
+    sessionId: string;
+    chatId: string;
+    assistantId: string;
+    status: TerminalMessageStatus;
+    model: string | null;
+    /** Partial accumulated text to persist; omit to leave the row's content untouched. */
+    content?: string;
+  },
+): Promise<boolean> {
+  const { sessionId, chatId, assistantId, status, model, content } = opts;
+  if (!assistantId) return false;
+
+  const rows =
+    content !== undefined
+      ? await sql<{ id: string }[]>`
+          UPDATE messages
+          SET content = ${content}, status = ${status}, finished_at = clock_timestamp()
+          WHERE id = ${assistantId} AND status = 'streaming'
+          RETURNING id
+        `
+      : await sql<{ id: string }[]>`
+          UPDATE messages
+          SET status = ${status}, finished_at = clock_timestamp()
+          WHERE id = ${assistantId} AND status = 'streaming'
+          RETURNING id
+        `;
+
+  if (rows.length === 0) return false;
+
+  publishFrame(sessionId, {
+    type: 'message_complete',
+    message_id: assistantId,
+    chat_id: chatId,
+    model,
+    status,
+  } as WsFrame);
+  return true;
+}