feat: sampling knobs + live PTY stream-json + token UI (v2.7.3)

Three small wins from boocode_code_review_v2 §1 #11/#7/#8.

#11 sampling knobs: top_n_sigma + dry_* family as first-class Agent fields,
threaded into the request body via providerOptions.openaiCompatible. Fixes a
latent bug — top_k (rejected by the AI-SDK provider) and min_p (never passed to
streamText) were dead on the wire; both now route through the same channel.
--reasoning-budget documented in data/AGENTS.md.

#7 live PTY stream-json: new stream-json-parser.ts line-buffers qwen/claude
NDJSON and emits text/reasoning/tool frames live + persists, with a fallback to
the old opaque slice. claude gets --output-format stream-json --verbose.

#8 token UI: agent_sessions input/output_tokens/cost now flow through the route
+ type and render beside the AgentComposerBar session chip.

Built by 3 parallel agents. Server 523 + coder 245 tests passing; builds + web
tsc clean. Builds on v2.7.2. openspec sampling-streamjson-tokens.

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 +11,11 @@ POSTGRES_PASSWORD=CHANGE_ME
 # point BooCode at a different SearXNG instance.
 SEARXNG_URL=http://100.114.205.53:8888
 
+# 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

@@ -16,3 +16,5 @@ data/*
 !data/AGENTS.md
 !data/skills/
 !data/mcp.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.

BOOCODER.md

@@ -37,3 +37,81 @@ 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 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)
+```

CHANGELOG.md

@@ -2,6 +2,122 @@
 
 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.
 
+## v2.7.3-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

@@ -2,7 +2,7 @@
 
 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. (Note: the root navigation `AGENTS.md` was removed in v1.12; `data/AGENTS.md` is the agent *registry*, not navigation.)
 
 ## What is BooCode
 
@@ -68,9 +68,9 @@ Key services:
 - **`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).
+- **`apps/coder/src/services/provider-registry.ts`** (BooCoder, NOT apps/server) — 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.
+- **`apps/coder/src/services/agent-probe.ts`** (BooCoder) — 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).
+- **`apps/coder/src/routes/providers.ts`** (BooCoder) — `GET /api/providers` returns installed providers with models. Transport field reflects actual capability (checks `supports_acp` from DB, not just registry preference). The apps/server side of this flow is the "Provider picker dispatch" bullet below.
 - **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`.
 
 Route registration: all routes registered in `index.ts` via `register*Routes(app, sql, ...)` functions. Routes are in `routes/*.ts`.
@@ -80,12 +80,19 @@ Route registration: all routes registered in `index.ts` via `register*Routes(app
 - 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`.
+- After `pnpm -C apps/coder build` the host `boocoder.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 returns that shape). Restart, don't re-debug.
 - 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.
+- **Provider snapshot lifecycle** (`apps/coder/src/services/`): `provider-config.ts` (Zod config, never-throws on bad input) → `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** (it's live runtime config — the coder reads AND writes it on UI toggles); the tracked reference is `data/coder-providers.example.json`. The loader falls back to `{providers:{}}` (built-ins only) when the live file is absent, so a fresh checkout needs no copy.
+- **opencode** runs as a warm HTTP server (v2.6 Phase 1, `services/backends/opencode-server.ts` — `opencode serve` per BooCoder process, one opencode session per BooCode session, resumed via `agent_sessions`). goose/qwen/claude still dispatch **one-shot** ACP/PTY with no ctx/token usage; only native `boocode` (llama-swap engine) tracks ctx. Paseo's per-provider native clients (design §12) deliberately not ported.
+- **opencode SSE** (`opencode-server.ts`): live streaming arrives as `session.next.text.delta` / `session.next.reasoning.delta` / `session.next.tool.{called,success,failed}` — NOT `message.part.*` (those are terminal/post-hoc). `client.event.subscribe({ directory })` MUST pass the session's worktree directory; omit it and opencode scopes events to the server's `process.cwd()` → zero session events (empty turns, 180s watchdog timeout). Per-session SSE (P1.5-a): each live session owns its own `event.subscribe({directory})` loop + AbortController, so concurrent sessions in different worktrees stream independently; 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 (`input:0`, empty turn).
+- **agent_sessions resume**: `config_hash = sha256('opencode_server|<model>')` — must NOT include the server port (random per boot; including it breaks cross-restart resume). P1.5-b: `agent_sessions` is keyed `(chat_id, agent)` — the tab/chat is the context unit (two opencode tabs in one session = two contexts sharing one worktree). `chat_id` CASCADEs from `chats`; `session_id`/`worktree_id` are informational `SET NULL`. The `worktrees` table (one-per-session, `session_id` SET NULL so it survives session delete) supersedes the defanged `session_worktrees`. `tasks.chat_id` threads the tab id to the dispatcher; `runOpenCodeServerTask` falls back to resolve-or-create a chat when it's null (arena/MCP/new_task). The `@opencode-ai/sdk` v2 client takes flattened params (`{sessionID, directory, parts, model:{providerID,modelID}}`), imports `createOpencodeClient` from `@opencode-ai/sdk/v2/client`.
 
 ### Frontend (`apps/web/src/`)
 
@@ -119,11 +126,11 @@ Font / CSS pipeline (apps/web):
 
 ### 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.
+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. v2.6.5: `workspace_panes` is now a `WorkspaceState` envelope `{panes, tabNumbers (chatId→stable session-scoped tab number, assigned on chat-pane open, retired on close, never reused), nextTabNumber, closedPaneStack (reopen LIFO, max 10, persisted so it survives reload)}` — not a bare `WorkspacePane[]`. Hydrate (`toWorkspaceState`) and the server PATCH validator (`z.union([array, envelope])` in `routes/sessions.ts`) both accept the legacy array and normalize to the envelope on read/write. Closing a chat pane relocates its tabs to the oldest chat/empty pane; `reopenPane` strips the restored chatIds from all live panes first (no duplication). `read_tab_by_number` resolves a number→chatId through `tabNumbers`.
 
 ## 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. 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. **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`. Both apply idempotently to the one `boochat` DB — so e.g. an `agent_sessions` FK change goes in the **coder** schema, not the server one. Idempotent FK-action flips (e.g. `ON DELETE CASCADE`→`SET NULL`) guard on `pg_constraint.confdeltype` so a re-run/fresh-deploy is a no-op (see the `session_worktrees`/`agent_sessions` defang blocks).
 
 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`.
 
@@ -145,10 +152,12 @@ BooCoder at port 9502: `curl http://100.114.205.53:9502/api/health`. Runs as `bo
 - 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).
+- The `boocode` container is `build: .` — it builds web+server from the **working tree**, so uncommitted changes deploy. Web edits are live on the Vite dev server (HMR) but NOT on production (`:9500` / code.indifferentketchup.com) until `docker compose up --build -d boocode`.
 - 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`.
 - 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 `${POSTGRES_PASSWORD}` from `.env` (`devpass`), NOT the literal in `.env`'s `DATABASE_URL=postgres://boocode:Ketchup1479@boocode_db:5432/...` line. Pattern: `describe.runIf(!!process.env.DATABASE_URL)(...)` with a `beforeAll` that applies the schema via `sql.unsafe(readFileSync(schemaPath))`. Tests skip cleanly when var is unset. `tool_cost_stats.test.ts` is the reference.
+- DB-integration tests opt-in via env var: `DATABASE_URL='postgres://boocode:devpass@localhost:5500/boochat' pnpm -C apps/server test`. Host port is 5500 (mapped from `boocode_db:5432`); password is `${POSTGRES_PASSWORD}` from `.env` (`devpass`), NOT the literal in `.env`'s `DATABASE_URL=postgres://boocode:Ketchup1479@boocode_db:5432/...` line. `psql` is not on the host PATH — for an interactive query use `docker exec boocode_db psql -U boocode -d boochat -c "..."`. 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`.
+- 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. Faster than bisecting source. 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 setting `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.
@@ -157,8 +166,8 @@ BooCoder at port 9502: `curl http://100.114.205.53:9502/api/health`. Runs as `bo
 - 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 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` 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 same boocode_gitea SSH key to `indifferentketchup/codecontext`. Build: `go build ./...`. Test: `go test ./...`. Docker rebuild: `docker compose build --no-cache codecontext`.
+- 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 requires staging the fork source 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 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.
 
@@ -171,17 +180,34 @@ BooCoder at port 9502: `curl http://100.114.205.53:9502/api/health`. Runs as `bo
 - 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.
+- `ui/` primitives present: button, card, context-menu, dialog, dropdown-menu, input, label, radio-group, sonner, textarea. No switch/sheet/drawer/badge/checkbox — use a `<button role="switch" aria-checked>` toggle (a hand-rolled `Switch` already lives in `SettingsPane.tsx`) and a Dialog-based panel for "drawers".
 - `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.
+- A scrollable list inside a Dialog on mobile: cap `DialogContent` (`max-h-[85vh]` + `grid-rows-[auto_minmax(0,1fr)_auto]`) and make the list the single scroll region with `overscroll-contain` — otherwise touch-scroll drags the whole fixed modal / chains to the page.
 - 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.
+- **DB/session-aware tools** take an optional 4th `ToolExecCtx { sql, sessionId }` arg on `ToolDef.execute`, plumbed `executeToolPhase`→`executeToolCall`→`execute`. It's optional so the filesystem tools and the `apps/coder` `ALL_TOOLS` consumer stay compatible; filesystem tools ignore it. `read_tab_by_number` (reads `sessions.workspace_panes` + the chat's messages via `sql`) is the reference.
 - **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).
+- React **StrictMode is on** (`main.tsx`): an updater passed to one `setState` that itself calls another `setState` (e.g. `setClosedPaneStack` inside a `setPanes` updater) is double-invoked in dev. Make such nested updates idempotent — `useWorkspacePanes`'s `appendClosed` dedupes a value-identical top entry for exactly this reason.
 - 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.
+- `data/AGENTS.md` is PARSED (`agents.ts` `splitSections`/`parseAgentSection`): each `## <Name>` is one agent and must be followed by a `---` frontmatter fence or the block throws; content before the first `## ` is discarded. Do NOT add free-form `## ` rule sections — they break the registry. Cross-cutting agent rules go in CLAUDE.md or a parser-ignored preamble.
+- Skills live in `data/skills/<vendor>/`; Sam's own namespace is `boocode/` (`committing-changes`, `using-worktrees`, `improving-boocode-guidance`) — `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.
 - 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.
+- **Sidecar routing** (`services/inference/provider.ts`): `upstreamModel(config, modelId, agent)` routes to `LLAMA_SIDECAR_URL` when agent has `llama_extra_args`, otherwise `LLAMA_SWAP_URL`. `resolveRoute(agent)` returns `{route: 'swap'|'sidecar', flags}`. Sidecar provider created fresh per call (not cached) because `X-Agent-Flags` header varies per agent. Boot-time guard in `index.ts` refuses to start if any agent has `llama_extra_args` but `LLAMA_SIDECAR_URL` is unset.
+- **Secret guard safe patterns** (`services/secret_guard.ts`): `.env.example`, `.env.sample`, `.env.template`, `.env.defaults` are allowlisted via `SAFE_PATTERNS` set. Do NOT add `.env.production`/`.env.development`/`.env.test` — those can hold real secrets.
+- **CoderPane uses ChatInput** (`components/panes/CoderPane.tsx`): shares the same `ChatInput` component as BooChat for full parity — attachments, paste-to-chip, auto-grow textarea, queued messages during send. CoderPane's `sendOneMessage` is the send callback; queued messages drain via `useEffect` when `sending` goes false.
+- **Adding a new `SessionEvent` type**: add the interface, add it to the `SessionEvent` union, add a `case` in `useSidebar.ts` `applyEvent` switch (no-op `return prev` is fine), and subscribe in any hook that needs it (e.g. `useSessionStream` for `refetch_messages`).
+- **BooCoder provider registry** (`apps/coder/src/services/provider-registry.ts`): static list of provider defs (boocode, opencode, goose, claude, qwen). `PROBED_AGENT_NAMES` derives from it. Adding/removing providers means editing this file, not the frontend.
+- **AgentComposerBar filters `e.installed`**: provider snapshot entries with `installed:false` (loading/unavailable) are dropped from the dropdown. `getProviderSnapshot` must await the full build — returning synchronous `loading` placeholders makes every provider vanish (the v2.5.7 "no providers showing up" regression); surfacing loading states needs a client poll.
+- **Coder↔web provider-type parity** (`apps/coder/src/services/provider-types.ts` ↔ `apps/web/src/api/types.ts`): enforced by runtime `provider-types-parity.test.ts` (compile-time cross-import is blocked by TS6307 on web's composite tsconfig). Mirror of the ws-frames parity pattern — edit both copies together or the test fails.
+- **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) instead discover from disk via `claude-command-discovery.ts` (`~/.claude/commands` + `enabledPlugins` `skills/`+`commands/`, 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 — BooChat passes flat `items` (unchanged).
+- **Pane header architecture (mobile vs desktop)**: Desktop coder pane header (BooCode label + [+] [×]) lives in `Workspace.tsx` gated by `isCoder && !isMobile`. Mobile coder controls (● ×) live in `Session.tsx` header row next to `MobileTabSwitcher`/`NewPaneMenu`. `AgentComposerBar` (provider/mode/model pickers) renders inside `CoderPane.tsx` on both. The ● status dot is passed via `connected` prop from CoderPane to AgentComposerBar.
+- **MessageBubble shared between BooChat and BooCoder** (`components/MessageBubble.tsx`): accepts optional `actions?: MessageActions` callbacks (onRegenerate, onResend, onFork, onDelete) and `hideActions?: ('fork'|'delete'|'openInPane')[]`. Defaults use BooChat API; CoderPane overrides via `CoderMessageList` props. `CoderTextBubble` was removed. **`CoderMessageList` passes `CoderMessageWire as unknown as Message`** — the coder wire shape lacks `metadata`/`kind`/`summary`, so those fields are `undefined` (not `null`) on coder messages. Null-guards on any `Message` field MUST use loose `!= null`, not strict `!== null` (`undefined !== null` is `true` → `.kind` throws → blank-screen crash). The `as unknown as` cast hides this from tsc; build + typecheck pass while runtime crashes.
+- **llama-sidecar** (`/opt/forks/llama-sidecar/`): Go daemon for per-agent llama-server process pool. Cross-compile: `GOOS=windows GOARCH=amd64 /snap/go/current/bin/go build -o bin/llama-sidecar.exe ./cmd/llama-sidecar`. Gitea: `indifferentketchup/llama-sidecar`. Windows child process gotchas: use `context.Background()` for child lifetime (not request ctx), `os.Open(os.DevNull)` for stdin, `os.Pipe()` for stdout with drain goroutine, `DETACHED_PROCESS | CREATE_NEW_PROCESS_GROUP` creation flags. SSH to sam-desktop: `ssh samki@100.101.41.16`; use `schtasks` for persistent process spawning (SSH `start /B` doesn't survive session close).

LICENSE

@@ -1,661 +1,21 @@
-                    GNU AFFERO GENERAL PUBLIC LICENSE
+MIT License
-                       Version 3, 19 November 2007
+
-
+Copyright (c) 2026 indifferentketchup
- Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+
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+Permission is hereby granted, free of charge, to any person obtaining a copy
- of this license document, but changing it is not allowed.
+of this software and associated documentation files (the "Software"), to deal
-
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-                            Preamble
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-
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-  The GNU Affero General Public License is a free, copyleft license for
+furnished to do so, subject to the following conditions:
-software and other kinds of works, specifically designed to ensure
+
-cooperation with the community in the case of network server software.
+The above copyright notice and this permission notice shall be included in all
-
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-  The licenses for most software and other practical works are designed
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-share and change all versions of a program--to make sure it remains free
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README.md

@@ -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

@@ -24,5 +24,5 @@
     "tsx": "^4.16.2",
     "typescript": "^5.5.0"
   },
-  "license": "AGPL-3.0-only"
+  "license": "MIT"
 }

apps/coder/.env.host

@@ -13,3 +13,4 @@ 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

apps/coder/package.json

@@ -16,6 +16,7 @@
     "@agentclientprotocol/sdk": "^0.22.1",
     "@boocode/server": "workspace:*",
     "@fastify/static": "^7.0.4",
+    "@opencode-ai/sdk": "~1.15.0",
     "@fastify/websocket": "^10.0.1",
     "@modelcontextprotocol/sdk": "^1.29.0",
     "fastify": "^4.28.1",
@@ -30,5 +31,5 @@
     "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

@@ -25,14 +25,20 @@ 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';
@@ -178,17 +184,46 @@ 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);
+  registerCheckpointRoutes(app, sql);
+  registerAgentSessionRoutes(app, sql);
   registerTaskRoutes(app, sql, inferenceApi);
   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

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__/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/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/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

@@ -224,8 +224,8 @@ 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)
+          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}, ${sessionId})
+          VALUES (${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

@@ -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 { pane_id, skill_name, provider, model, mode_id, thinking_option_id } = parsed.data;
-      const sessionRows = await sql<{ id: string }[]>`
+      const sessionRows = await sql<{ id: string; project_id: string }[]>`
-        SELECT id FROM sessions WHERE id = ${sessionId}
+        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/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/worktrees.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/schema.sql

@@ -66,8 +66,216 @@ 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;
+
+-- v2.6: one shared worktree per session (all agents/panes in the session operate in it).
+CREATE TABLE IF NOT EXISTS session_worktrees (
+  session_id UUID PRIMARY KEY REFERENCES sessions(id) ON DELETE CASCADE,
+  worktree_path TEXT NOT NULL,
+  base_commit TEXT,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+-- P1.5-b: DEFANG the CASCADE — a session delete must no longer wipe its worktree
+-- row. This table is SUPERSEDED by `worktrees` below; all readers are repointed
+-- this phase, so the row just persists (dead) on session delete until a later
+-- cleanup drops the table. session_id is this table's PRIMARY KEY, so it cannot be
+-- nullable → SET NULL is invalid and NO ACTION/RESTRICT would block deletes; the
+-- only valid defang is to drop the FK with no replacement. Idempotent: only fires
+-- while the FK is still ON DELETE CASCADE ('c').
+DO $$ BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_constraint
+    WHERE conname = 'session_worktrees_session_id_fkey'
+      AND confdeltype = 'c'
+  ) THEN
+    ALTER TABLE session_worktrees DROP CONSTRAINT session_worktrees_session_id_fkey;
+  END IF;
+END $$;
+
+-- 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';
+
+-- Migrate any surviving session_worktrees rows → worktrees (idempotent; 0 rows
+-- after the test-session delete, kept for generality / fresh-DB safety).
+INSERT INTO worktrees (session_id, path, branch, base_commit, status)
+SELECT sw.session_id, sw.worktree_path, 'session-' || sw.session_id, sw.base_commit, 'active'
+FROM session_worktrees sw
+WHERE NOT EXISTS (SELECT 1 FROM worktrees w WHERE w.session_id = sw.session_id AND w.status='active');
+
+-- 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);
+
+-- 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-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__/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__/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__/provider-types-parity.test.ts

@@ -0,0 +1,64 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { resolve, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+/**
+ * Parity guard between the two copies of the provider snapshot types:
+ *   apps/coder/src/services/provider-types.ts  (backend source of truth)
+ *   apps/web/src/api/types.ts                  (web wire copy)
+ *
+ * APPROACH: text-identity of each shared type block (mirrors the repo's existing
+ * ws-frames.test.ts byte-parity convention). A compile-time bidirectional-
+ * assignability check was attempted first (a web-side file importing coder's
+ * import-free provider-types.ts), but apps/web/tsconfig.app.json is a composite
+ * project and rejects out-of-include files with TS6307 — so cross-project type
+ * import is structurally blocked. This runtime guard FAILS on any field
+ * add/remove/rename/loosen in either copy, including the nested model/mode/
+ * command types that ProviderSnapshotEntry references. Single-source-of-truth
+ * (shared workspace package) is deferred as a Tier-2 follow-up.
+ */
+const here = dirname(fileURLToPath(import.meta.url));
+const coderSrc = readFileSync(resolve(here, '../provider-types.ts'), 'utf8');
+const webSrc = readFileSync(resolve(here, '../../../../web/src/api/types.ts'), 'utf8');
+
+function extractBlock(src: string, name: string): string {
+  const iface = src.match(new RegExp(`export interface ${name} \\{[\\s\\S]*?\\n\\}`));
+  const alias = src.match(new RegExp(`export type ${name} =[^;]*;`));
+  const block = iface?.[0] ?? alias?.[0];
+  if (!block) throw new Error(`type block '${name}' not found`);
+  // Normalize to type structure: drop blank + comment lines (//, /* */, *),
+  // trim each line. Field add/remove/rename/loosen still changes a field line.
+  return block
+    .split('\n')
+    .map((l) => l.trim())
+    .filter(
+      (l) =>
+        l.length > 0 &&
+        !l.startsWith('//') &&
+        !l.startsWith('/*') &&
+        !l.startsWith('*'),
+    )
+    .join('\n');
+}
+
+describe('provider snapshot type parity (coder ↔ web)', () => {
+  // Includes the nested types ProviderSnapshotEntry references, so structural
+  // drift anywhere in the snapshot surface is caught.
+  const names = [
+    'ProviderSnapshotStatus',
+    'ProviderSnapshotEntry',
+    'ProviderModel',
+    'ProviderMode',
+    'ThinkingOption',
+    'AgentCommand',
+  ];
+  for (const name of names) {
+    it(`${name} is identical in both copies`, () => {
+      expect(
+        extractBlock(webSrc, name),
+        `${name} drifted between apps/coder/src/services/provider-types.ts and apps/web/src/api/types.ts`,
+      ).toBe(extractBlock(coderSrc, name));
+    });
+  }
+});

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);
+  const absolute = resolveInWorktree(worktreePath, filePath);
-  if (!absolute.startsWith(resolve(worktreePath))) {
-    throw new Error(`path escapes worktree: ${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);
+  const absolute = resolveInWorktree(worktreePath, filePath);
-  if (!absolute.startsWith(resolve(worktreePath))) {
-    throw new Error(`path escapes worktree: ${filePath}`);
-  }
   await fs.mkdir(dirname(absolute), { recursive: true });
   await fs.writeFile(absolute, content, 'utf8');
 }

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

@@ -26,14 +26,15 @@ 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 { mapSessionUpdate } from './acp-event-map.js';
 import {
   type AcpToolSnapshot,
-  mergeToolSnapshot,
   snapshotToWireToolCall,
   synthesizeCanceledSnapshots,
 } from './acp-tool-snapshot.js';
@@ -59,6 +60,9 @@ 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;
 }
@@ -155,63 +159,47 @@ class AcpStreamContext {
     } 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;
+    // v2.6 Phase 2: the case-by-case mapping now lives in the shared, pure
-    switch (update.sessionUpdate) {
+    // `mapSessionUpdate` (reused by the warm ACP backend). This method keeps the
-      case 'agent_message_chunk': {
+    // identical broker-publishing side effects — it just translates the normalized
-        const content = update.content;
+    // AgentEvents back into the same frames it always emitted. `this.toolSnapshots`
-        if (content.type === 'text' && 'text' in content) {
+    // is the merge accumulator, so a later tool_call_update merges over its
-          const text = (content as { text: string }).text;
+    // tool_call (the prior `handleToolUpdate` behavior, byte-for-byte).
-          this.textChunks.push(text);
+    for (const event of mapSessionUpdate(params, this.toolSnapshots)) {
+      switch (event.type) {
+        case 'text':
+          this.textChunks.push(event.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,
+              content: event.text,
             } as WsFrame);
           }
-        }
           break;
-      }
+        case 'reasoning':
-      case 'agent_thought_chunk': {
+          this.reasoningChunks.push(event.text);
-        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,
+              content: event.text,
             } as WsFrame);
           }
-        }
           break;
-      }
         case 'tool_call':
-        this.handleToolUpdate(update.toolCallId, update);
+        case 'tool_update':
+          // mapSessionUpdate already stored the merged snapshot in this.toolSnapshots.
+          this.publishToolSnapshot(event.toolCall);
           break;
-      case 'tool_call_update':
+        case 'commands':
-        this.handleToolUpdate(update.toolCallId, update);
+          if (this.opts.taskId && event.commands.length > 0) {
-        break;
+            mergeTaskCommands(this.opts.taskId, event.commands);
-      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;
+              const all = getTaskCommands(this.opts.taskId) ?? event.commands;
               this.opts.broker!.publishFrame(this.opts.sessionId, {
                 type: 'agent_commands',
                 task_id: this.opts.taskId,
@@ -222,8 +210,6 @@ class AcpStreamContext {
           }
           break;
       }
-      default:
-        break;
     }
   }
 
@@ -282,8 +268,12 @@ export async function dispatchViaAcp(opts: AcpDispatchOpts): Promise<AcpDispatch
     broker,
   } = opts;
 
-  const args = resolveAcpSpawnArgs(agent);
+  // v2.3 phase 3: launch from the resolved registry def (config override /
-  if (!args) {
+  // 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 +283,11 @@ export async function dispatchViaAcp(opts: AcpDispatchOpts): Promise<AcpDispatch
     };
   }
 
-  const binary = installPath ?? agent;
+  log.info({ agent, binary: spec.binary, worktreePath, modeId, model: opts.model }, 'acp-dispatch: spawning');
-  log.info({ agent, binary, worktreePath, modeId, model: opts.model }, 'acp-dispatch: spawning');
+  const child = spawn(spec.binary, spec.args, {
-  const child = spawn(binary, 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) {
+ * v2.3 phase 3: resolve the launch spec for an ACP dispatch (design.md §5.1).
-    case 'cursor':
+ * Consults the resolved registry's launchCommand (config override or custom-ACP
-      return ['cursor-agent', 'agent'];
+ * entry) first; otherwise falls back to the built-in default argv above.
-    case 'copilot':
+ *
-      return ['copilot'];
+ * Byte-identical to pre-v2.3 for built-ins with no override: binary is
-    default:
+ * `installPath ?? id` and args come from resolveAcpSpawnArgs — exactly the
-      return [agent];
+ * `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/agent-backend.ts

@@ -0,0 +1,119 @@
+/**
+ * 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';
+
+/**
+ * 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;
+}
+
+/**
+ * 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 path = await whichBinary(bin);
-      const { stdout } = await exec(`which ${bin}`, { timeout: 10_000 });
-      const path = stdout.trim();
     if (path) return path;
-    } catch {
-      /* try next */
-    }
   }
   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);
+      // Custom ACP entries are ACP by declaration; built-ins detect support.
-      let supportsAcp = providerDef?.transport === 'acp';
+      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 (!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)');
+          }
+        }
+      }
 
-      const label = providerDef?.label ?? agentName;
+      const label = resolved.configLabel ?? resolved.label;
-      const transport =
+      const transport = resolved.isCustomAcp
-        providerDef?.transport === 'acp' && !supportsAcp ? 'pty' : (providerDef?.transport ?? 'pty');
+        ? '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/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-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__/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/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-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/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 +1,417 @@
+/**
+ * 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,
+  type SessionNotification,
+  type RequestPermissionRequest,
+  type RequestPermissionResponse,
+  type ReadTextFileRequest,
+  type ReadTextFileResponse,
+  type WriteTextFileRequest,
+  type WriteTextFileResponse,
+  type CreateTerminalRequest,
+  type CreateTerminalResponse,
+  type CreateElicitationRequest,
+  type CreateElicitationResponse,
+} 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 { readWorktreeTextFile, writeWorktreeTextFile } from '../acp-client-fs.js';
+import { waitForPermissionResponse, waitForElicitationResponse, 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. They read `this.activeTurn`
+   *  so each turn's events/permissions route to the right place — exactly the
+   *  opencode-server `activeTurn` pattern. Worktree-scoped FS like AcpStreamContext. */
+  private buildClient(worktreePath: string): Client {
+    return {
+      sessionUpdate: async (params: SessionNotification): Promise<void> => {
+        const turn = this.activeTurn;
+        if (!turn) return; // between turns — drop (no orphan settles a future turn)
+        for (const event of mapSessionUpdate(params, turn.snapshots)) {
+          turn.onEvent(event);
+        }
+      },
+      requestPermission: async (params: RequestPermissionRequest): Promise<RequestPermissionResponse> => {
+        const turn = this.activeTurn;
+        if (turn?.taskId) {
+          // Route to the UI via the per-turn task id (same as the one-shot path).
+          return waitForPermissionResponse(turn.taskId, turn.sessionId, this.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 = this.activeTurn;
+        if (turn?.taskId) {
+          return waitForElicitationResponse(turn.taskId, turn.sessionId, this.agent, turn.modeId, params);
+        }
+        return { action: 'decline' };
+      },
+    };
+  }
+
+  // ─── 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' };
+    }
+
+    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/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/dispatcher.ts

@@ -3,12 +3,21 @@ import type { FastifyBaseLogger } from 'fastify';
 import type { Broker } from '@boocode/server/broker';
 import type { WsFrame } from '@boocode/server/ws-frames';
 import type { Config } from '../config.js';
-import { createWorktree, diffWorktree, cleanupWorktree } from './worktrees.js';
+import { createWorktree, diffWorktree, cleanupWorktree, ensureSessionWorktree } from './worktrees.js';
+import { createCheckpoint } from './checkpoints.js';
+import { makeDcpStreamStripper } from './dcp-strip.js';
 import { dispatchViaAcp } from './acp-dispatch.js';
+import { getResolvedRegistry } from './provider-config-registry.js';
 import { dispatchViaPty } from './pty-dispatch.js';
 import { clearTaskCommands, setTaskCommands } from './agent-commands-cache.js';
 import { getManifestCommands } from './provider-commands.js';
 import { persistExternalAgentTurn } from './agent-turn-persist.js';
+import { snapshotToWireToolCall, type AcpToolSnapshot } from './acp-tool-snapshot.js';
+import { agentPool, OPENCODE_POOL_KEY } from './agent-pool.js';
+import { OpenCodeServerBackend } from './backends/opencode-server.js';
+import { WarmAcpBackend } from './backends/warm-acp.js';
+import { shouldUseWarmBackend } from './backends/warm-acp-routing.js';
+import type { AgentBackend, AgentEvent } from './agent-backend.js';
 
 interface InferenceRunner {
   enqueue: (sessionId: string, chatId: string, assistantId: string, user: string) => void;
@@ -24,20 +33,45 @@ interface Deps {
   config: Config;
 }
 
-const POLL_INTERVAL_MS = 5_000;
+// LISTEN/NOTIFY ('tasks_new') is the fast path — the dispatcher reacts to new
+// tasks immediately. The poll is only a safety net for notifications missed
+// during a listen-connection drop (porsager auto-reconnects), so it can stay slow.
+const POLL_INTERVAL_MS = 2_000;
 const COMPLETION_POLL_MS = 2_000;
 
 export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<void> } {
   const { sql, inference, broker, log, config } = deps;
   let timer: ReturnType<typeof setInterval> | null = null;
-  let running = false;
+  let listener: { unlisten: () => Promise<void> } | null = null;
+  let polling = false;
   let stopping = false;
-  let inflightPromise: Promise<void> | null = null;
+  // v2.6 (1.9): per-session in-flight registry replaces the global `running`
+  // boolean. Key = session_id (or `task:<id>` for sessionless tasks). Sessions
+  // without an in-flight turn run concurrently; within a session, strictly one
+  // turn at a time.
+  const inflight = new Map<string, Promise<void>>();
+
+  // Shared entry point for both the poll timer and the NOTIFY listener. poll()'s
+  // `polling`/`stopping` guard makes this safe to call concurrently — a notify
+  // arriving mid-poll returns immediately and never double-dispatches.
+  function triggerPoll(reason: string): void {
+    poll().catch((err) => {
+      log.error({ err, reason }, 'dispatcher: poll error');
+    });
+  }
+
+  function concurrencyKey(task: { id: string; session_id: string | null }): string {
+    return task.session_id ?? `task:${task.id}`;
+  }
 
   async function poll(): Promise<void> {
-    if (running || stopping) return;
+    // `polling` serializes poll() execution itself (timer + NOTIFY can fire
-
+    // concurrently) so we never double-select a task. It does NOT serialize task
-    // Grab one pending task
+    // execution — that's what `inflight` (keyed per session) governs.
+    if (polling || stopping) return;
+    polling = true;
+    try {
+      // Oldest-first; start every pending task whose session isn't already busy.
       const rows = await sql<{
         id: string;
         project_id: string;
@@ -47,21 +81,28 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         mode_id: string | null;
         thinking_option_id: string | null;
         session_id: string | null;
+        chat_id: string | null;
       }[]>`
-      SELECT id, project_id, input, agent, model, mode_id, thinking_option_id, session_id
+        SELECT id, project_id, input, agent, model, mode_id, thinking_option_id, session_id, chat_id
         FROM tasks
         WHERE state = 'pending'
         ORDER BY created_at
-      LIMIT 1
+        LIMIT 50
       `;
-    if (rows.length === 0) return;
+      for (const task of rows) {
-
+        if (stopping) break;
-    const task = rows[0]!;
+        const key = concurrencyKey(task);
-    running = true;
+        if (inflight.has(key)) continue; // this session already has an in-flight turn
-    inflightPromise = runTask(task).finally(() => {
+        // Register synchronously (before any await) so a later row in this pass
-      running = false;
+        // with the same key is skipped and a concurrent poll can't re-pick it.
-      inflightPromise = null;
+        const p = runTask(task).finally(() => {
+          inflight.delete(key);
         });
+        inflight.set(key, p);
+      }
+    } finally {
+      polling = false;
+    }
   }
 
   async function runTask(task: {
@@ -73,6 +114,7 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
     mode_id: string | null;
     thinking_option_id: string | null;
     session_id: string | null;
+    chat_id: string | null;
   }): Promise<void> {
     const taskId = task.id;
 
@@ -82,7 +124,18 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         SELECT name, supports_acp, install_path FROM available_agents WHERE name = ${task.agent}
       `;
       if (agentRow) {
+        // v2.6 (1.7): opencode routes to its warm HTTP-server backend.
+        // v2.6 Phase 2 (2.4): goose/qwen route to the warm ACP backend WHEN the
+        // task came from a real chat tab (session_id + chat_id) — shouldUseWarmBackend.
+        // Session-less creators (arena, MCP, new_task, generic /api/tasks) keep the
+        // existing one-shot worktree-per-task ACP/PTY path untouched.
+        if (task.agent === 'opencode') {
+          await runOpenCodeServerTask(task, agentRow.install_path);
+        } else if (shouldUseWarmBackend(task)) {
+          await runWarmAcpTask(task, agentRow.install_path);
+        } else {
           await runExternalAgent(task, agentRow.supports_acp, agentRow.install_path);
+        }
         return;
       }
       // Agent specified but not available — fall through to Path A with a warning
@@ -306,6 +359,16 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
       `;
       const assistantId = assistantMsg!.id;
 
+      // write-edit-robustness #4: pre-turn worktree checkpoint (best-effort; a
+      // failure logs and never breaks dispatch). This path uses a per-task worktree
+      // (createWorktree, not the session worktree), so there's no worktrees-table id
+      // — pass null for worktreeId, the path is enough for restore's reset.
+      await createCheckpoint(
+        sql,
+        { chatId, sessionId, worktreeId: null, worktreePath, messageId: assistantId },
+        { signal: ac.signal, log },
+      ).catch(() => null);
+
       broker.publishFrame(sessionId, {
         type: 'message_started',
         message_id: assistantId,
@@ -327,6 +390,7 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
       if (supportsAcp) {
         const result = await dispatchViaAcp({
           agent,
+          resolved: getResolvedRegistry().get(agent),
           task: task.input,
           worktreePath,
           installPath: installPath ?? undefined,
@@ -346,6 +410,52 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         outputSummary = result.output.slice(0, 500);
         await persistExternalAgentTurn(sql, assistantId, result.toolSnapshots, acpReasoning);
       } else {
+        // v#7 (stream-json): claude + qwen run with --output-format stream-json.
+        // Parse the NDJSON live in pty-dispatch and forward AgentEvents here so we
+        // publish the SAME live frames the warm-ACP / opencode paths emit (text,
+        // reasoning, tool) and persist structured parts. Accumulate for the final
+        // message content + persistence; fall back to the opaque stdout slice when
+        // nothing parsed (agent ran without the flag, or crashed before emitting).
+        const ptyTextChunks: string[] = [];
+        const ptyReasoningChunks: string[] = [];
+        const ptyToolSnaps = new Map<string, AcpToolSnapshot>();
+
+        const onPtyEvent = (e: AgentEvent): void => {
+          switch (e.type) {
+            case 'text':
+              ptyTextChunks.push(e.text);
+              broker.publishFrame(sessionId, {
+                type: 'delta',
+                message_id: assistantId,
+                chat_id: chatId,
+                content: e.text,
+              } as WsFrame);
+              break;
+            case 'reasoning':
+              ptyReasoningChunks.push(e.text);
+              broker.publishFrame(sessionId, {
+                type: 'reasoning_delta',
+                message_id: assistantId,
+                chat_id: chatId,
+                content: e.text,
+              } as WsFrame);
+              break;
+            case 'tool_call':
+            case 'tool_update':
+              ptyToolSnaps.set(e.toolCall.toolCallId, e.toolCall);
+              broker.publishFrame(sessionId, {
+                type: 'tool_call',
+                message_id: assistantId,
+                chat_id: chatId,
+                tool_call: snapshotToWireToolCall(e.toolCall),
+              } as WsFrame);
+              break;
+            case 'commands':
+              // stream-json carries no commands today; ignore if it ever does.
+              break;
+          }
+        };
+
         const result = await dispatchViaPty({
           agent,
           task: task.input,
@@ -356,7 +466,22 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
           thinkingOptionId: task.thinking_option_id ?? undefined,
           signal: ac.signal,
           log,
+          onEvent: onPtyEvent,
         });
+
+        if (result.streamed) {
+          assistantContent = ptyTextChunks.join('').slice(0, 50_000);
+          // stream-json text can be empty for a tool-only turn — surface stderr or a
+          // placeholder so the message row isn't blank.
+          if (!assistantContent) {
+            assistantContent = (result.stderr || '(no text output)').slice(0, 50_000);
+          }
+          outputSummary = (ptyTextChunks.join('') || result.stderr).slice(0, 500);
+          acpReasoning = ptyReasoningChunks.join('').slice(0, 200_000);
+          await persistExternalAgentTurn(sql, assistantId, [...ptyToolSnaps.values()], acpReasoning);
+        } else {
+          // Fallback: agent produced no parseable NDJSON (ran without the flag, or
+          // crashed). Preserve today's opaque stdout-slice + single delta behavior.
           assistantContent = (result.stdout || result.stderr || '(no output)').slice(0, 50_000);
           outputSummary = (result.stdout || result.stderr).slice(0, 500);
 
@@ -369,6 +494,7 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
             } as WsFrame);
           }
         }
+      }
 
       await sql`
         UPDATE messages
@@ -395,10 +521,11 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
       const diff = await diffWorktree(worktreePath, projectPath, { signal: ac.signal });
 
       if (diff) {
-        // Queue a single pending_change entry with the full unified diff
+        // Queue a single pending_change entry with the full unified diff, stamped
+        // with the dispatched agent for DiffPanel attribution (v2.6 Phase 1-UX).
         await sql`
-          INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff)
+          INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff, agent)
-          VALUES (${sessionId}, ${taskId}, ${projectPath}, 'edit', ${diff})
+          VALUES (${sessionId}, ${taskId}, ${projectPath}, 'edit', ${diff}, ${agent})
         `;
         log.info({ taskId, diffLength: diff.length }, 'dispatcher: diff queued as pending change');
       } else {
@@ -441,6 +568,567 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
     }
   }
 
+  // ─── Path B (opencode): warm OpenCode server backend (v2.6 1.7 + 1.10) ───────
+
+  // OpenCode runs ONE server per BooCoder process, shared across all sessions
+  // (the backend multiplexes sessions internally), so it's pooled under a fixed
+  // key (OPENCODE_POOL_KEY, shared with the lifecycle close-hook) rather than
+  // per-session. Warm ACP backends (Phase 2) are per (chat, agent).
+  function getOpenCodeBackend(installPath: string | null): AgentBackend {
+    let backend = agentPool.get(OPENCODE_POOL_KEY, 'opencode');
+    if (!backend) {
+      backend = new OpenCodeServerBackend({ sql, log, opencodeBinary: installPath ?? 'opencode' });
+      agentPool.register(OPENCODE_POOL_KEY, 'opencode', backend);
+    }
+    return backend;
+  }
+
+  async function runOpenCodeServerTask(
+    task: {
+      id: string;
+      project_id: string;
+      input: string;
+      agent: string | null;
+      model: string | null;
+      mode_id: string | null;
+      thinking_option_id: string | null;
+      session_id: string | null;
+      chat_id: string | null;
+    },
+    installPath: string | null,
+  ): Promise<void> {
+    const taskId = task.id;
+    const agent = 'opencode';
+    log.info({ taskId, agent }, 'dispatcher: starting task (path B — opencode server)');
+
+    const [project] = await sql<{ path: string | null }[]>`
+      SELECT path FROM projects WHERE id = ${task.project_id}
+    `;
+    const projectPath = project?.path;
+    if (!projectPath) {
+      await sql`
+        UPDATE tasks
+        SET state = 'failed', ended_at = clock_timestamp(), output_summary = 'Project has no path — cannot create worktree'
+        WHERE id = ${taskId}
+      `;
+      return;
+    }
+
+    const ac = new AbortController();
+
+    try {
+      // execution_path = 'acp' — the schema CHECK has no 'opencode_server' value
+      // (schema is frozen at Phase 0); the warm-vs-one-shot distinction lives in
+      // agent_sessions.backend. Reuse the closest existing value.
+      await sql`
+        UPDATE tasks
+        SET state = 'running', started_at = clock_timestamp(), execution_path = 'acp'
+        WHERE id = ${taskId}
+      `;
+
+      // Resolve session + chat. P1.5-b: the chat (tab) is the context key, so the
+      // chat_id MUST be non-null and stable before ensureSession. The coder message
+      // route + skills route stamp task.chat_id with the frontend tab's chat — use
+      // it directly. Session-less creators (arena, MCP, new_task, generic
+      // /api/tasks) leave it null; fall back to resolving/creating a real chat so
+      // ensureSession never receives a degenerate (null, agent) key.
+      let sessionId: string;
+      let chatId: string;
+      if (task.chat_id && task.session_id) {
+        sessionId = task.session_id;
+        chatId = task.chat_id;
+      } else if (task.session_id) {
+        sessionId = task.session_id;
+        const chats = await sql<{ id: string }[]>`
+          SELECT id FROM chats WHERE session_id = ${sessionId} AND status = 'open' ORDER BY created_at DESC LIMIT 1
+        `;
+        if (chats.length === 0) {
+          const [chat] = await sql<{ id: string }[]>`
+            INSERT INTO chats (session_id, name, status)
+            VALUES (${sessionId}, 'External agent execution', 'open')
+            RETURNING id
+          `;
+          chatId = chat!.id;
+        } else {
+          chatId = chats[0]!.id;
+        }
+      } else {
+        const sessionName = `Task [${agent}]: ${task.input.slice(0, 30)}`;
+        const [session] = await sql<{ id: string }[]>`
+          INSERT INTO sessions (project_id, name, model, status)
+          VALUES (${task.project_id}, ${sessionName}, ${task.model ?? config.DEFAULT_MODEL}, 'open')
+          RETURNING id
+        `;
+        sessionId = session!.id;
+        const [chat] = await sql<{ id: string }[]>`
+          INSERT INTO chats (session_id, name, status)
+          VALUES (${sessionId}, 'External agent execution', 'open')
+          RETURNING id
+        `;
+        chatId = chat!.id;
+        await sql`UPDATE tasks SET session_id = ${sessionId} WHERE id = ${taskId}`;
+      }
+
+      if (!task.session_id) {
+        await sql`
+          INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+          VALUES (${sessionId}, ${chatId}, 'user', ${task.input}, 'complete', clock_timestamp())
+        `;
+      }
+
+      // Persistent, session-keyed worktree (shared across turns; NOT torn down
+      // per turn — Phase 3 reaps it). Captures base_commit for a stable diff.
+      const { worktreeId, worktreePath, baseCommit } = await ensureSessionWorktree(sql, projectPath, sessionId, {
+        signal: ac.signal,
+      });
+      log.info({ taskId, worktreePath }, 'dispatcher: session worktree ready');
+
+      const [assistantMsg] = await sql<{ id: string }[]>`
+        INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+        VALUES (${sessionId}, ${chatId}, 'assistant', '', 'streaming', clock_timestamp())
+        RETURNING id
+      `;
+      const assistantId = assistantMsg!.id;
+
+      // write-edit-robustness #4: pre-turn checkpoint of the persistent session
+      // worktree (best-effort; never breaks dispatch). worktreeId comes from the
+      // worktrees table (ensureSessionWorktree above).
+      await createCheckpoint(
+        sql,
+        { chatId, sessionId, worktreeId, worktreePath, messageId: assistantId },
+        { signal: ac.signal, log },
+      ).catch(() => null);
+
+      broker.publishFrame(sessionId, {
+        type: 'message_started',
+        message_id: assistantId,
+        chat_id: chatId,
+        role: 'assistant',
+      } as WsFrame);
+
+      const manifestCommands = getManifestCommands(agent);
+      if (manifestCommands.length > 0) {
+        setTaskCommands(taskId, manifestCommands);
+        broker.publishFrame(sessionId, {
+          type: 'agent_commands',
+          task_id: taskId,
+          session_id: sessionId,
+          commands: manifestCommands,
+        } as WsFrame);
+      }
+
+      // Accumulate the turn's stream for persistence + the final message content.
+      const textChunks: string[] = [];
+      const reasoningChunks: string[] = [];
+      const toolSnaps = new Map<string, AcpToolSnapshot>();
+      // opencode's dcp plugin appends <dcp-message-id>…</dcp-message-id> to the
+      // text, streamed split across deltas — a per-chunk regex misses it (see
+      // dcp-strip.ts). Buffer text through a cross-chunk stripper so neither the
+      // live `delta` frames nor the persisted content ever carry the tag.
+      const dcp = makeDcpStreamStripper();
+
+      // Map transport-agnostic AgentEvents → the SAME WS frames the ACP path emits.
+      // This boundary is where message_id/chat_id get attached (the backend never
+      // owns them).
+      const onEvent = (e: AgentEvent): void => {
+        switch (e.type) {
+          case 'text': {
+            const safe = dcp.push(e.text);
+            if (safe) {
+              textChunks.push(safe);
+              broker.publishFrame(sessionId, {
+                type: 'delta',
+                message_id: assistantId,
+                chat_id: chatId,
+                content: safe,
+              } as WsFrame);
+            }
+            break;
+          }
+          case 'reasoning':
+            reasoningChunks.push(e.text);
+            broker.publishFrame(sessionId, {
+              type: 'reasoning_delta',
+              message_id: assistantId,
+              chat_id: chatId,
+              content: e.text,
+            } as WsFrame);
+            break;
+          case 'tool_call':
+          case 'tool_update':
+            toolSnaps.set(e.toolCall.toolCallId, e.toolCall);
+            broker.publishFrame(sessionId, {
+              type: 'tool_call',
+              message_id: assistantId,
+              chat_id: chatId,
+              tool_call: snapshotToWireToolCall(e.toolCall),
+            } as WsFrame);
+            break;
+          case 'commands':
+            // opencode-server doesn't emit these today; ignore if it ever does.
+            break;
+        }
+      };
+
+      // opencode expects provider-prefixed model ids (e.g. 'llama-swap/qwen3.6-35b…').
+      // DEFAULT_MODEL is bare (no prefix) because native inference uses it directly
+      // against llama-swap. Coalesce empty string (frontend sends '' when no models
+      // listed) and prefix bare ids so parseModel always succeeds.
+      const rawModel = (task.model && task.model.trim()) || config.DEFAULT_MODEL;
+      const model = rawModel.includes('/') ? rawModel : `llama-swap/${rawModel}`;
+      const backend = getOpenCodeBackend(installPath);
+      const handle = await backend.ensureSession(sessionId, {
+        agent,
+        model,
+        chatId,
+        worktreePath,
+        worktreeId,
+        projectId: task.project_id,
+      });
+      const result = await backend.prompt(handle, task.input, {
+        worktreePath,
+        model,
+        signal: ac.signal,
+        onEvent,
+      });
+      // Phase 3: keep the pooled backend's slot warm across this (possibly long)
+      // turn so the idle sweep measures from turn END, not start.
+      agentPool.touch(OPENCODE_POOL_KEY, agent);
+
+      // Flush any text held back mid-tag at stream end (complete tags stripped).
+      const dcpTail = dcp.flush();
+      if (dcpTail) {
+        textChunks.push(dcpTail);
+        broker.publishFrame(sessionId, {
+          type: 'delta',
+          message_id: assistantId,
+          chat_id: chatId,
+          content: dcpTail,
+        } as WsFrame);
+      }
+
+      const assistantContent = textChunks.join('').slice(0, 50_000);
+      const reasoningText = reasoningChunks.join('').slice(0, 200_000);
+      const outputSummary = (result.ok ? textChunks.join('') : result.error ?? 'opencode turn failed').slice(0, 500);
+
+      await persistExternalAgentTurn(sql, assistantId, [...toolSnaps.values()], reasoningText);
+
+      await sql`
+        UPDATE messages
+        SET content = ${assistantContent}, status = 'complete', finished_at = clock_timestamp()
+        WHERE id = ${assistantId}
+      `;
+      broker.publishFrame(sessionId, {
+        type: 'message_complete',
+        message_id: assistantId,
+        chat_id: chatId,
+      } as WsFrame);
+
+      if (stopping) {
+        await sql`UPDATE tasks SET state = 'cancelled', ended_at = clock_timestamp() WHERE id = ${taskId}`;
+        return; // worktree persists (no cleanup); backend stays warm
+      }
+
+      // 1.10: diff the persistent worktree against its captured baseline and
+      // SUPERSEDE the session's prior pending row (latest-wins, one accumulating
+      // diff) instead of stacking. Stamp agent for DiffPanel attribution.
+      const diff = await diffWorktree(worktreePath, projectPath, {
+        signal: ac.signal,
+        baseRef: baseCommit ?? 'HEAD',
+      });
+      if (diff) {
+        await sql`
+          DELETE FROM pending_changes WHERE session_id = ${sessionId} AND status = 'pending'
+        `;
+        await sql`
+          INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff, agent)
+          VALUES (${sessionId}, ${taskId}, ${projectPath}, 'edit', ${diff}, ${agent})
+        `;
+        log.info({ taskId, diffLength: diff.length }, 'dispatcher: diff superseded prior pending change');
+      } else {
+        log.info({ taskId }, 'dispatcher: no changes detected in session worktree');
+      }
+
+      // NO worktree cleanup — it's persistent (Phase 3 reaps it). Backend stays warm.
+
+      const [extCostRow] = await sql<{ total: number | null }[]>`
+        SELECT SUM(tokens_used)::int AS total
+        FROM messages
+        WHERE session_id = ${sessionId} AND tokens_used IS NOT NULL
+      `;
+      const extCostTokens = extCostRow?.total ?? null;
+
+      const finalState = result.ok ? 'completed' : 'failed';
+      await sql`
+        UPDATE tasks
+        SET state = ${finalState}, ended_at = clock_timestamp(), output_summary = ${outputSummary}, cost_tokens = ${extCostTokens}
+        WHERE id = ${taskId}
+      `;
+      log.info({ taskId, agent, finalState, costTokens: extCostTokens }, 'dispatcher: task finished (opencode server)');
+      clearTaskCommands(taskId);
+    } catch (err) {
+      const errMsg = err instanceof Error ? err.message : String(err);
+      log.error({ taskId, agent, err: errMsg }, 'dispatcher: opencode server error');
+      await sql`
+        UPDATE tasks
+        SET state = 'failed', ended_at = clock_timestamp(), output_summary = ${errMsg.slice(0, 500)}
+        WHERE id = ${taskId}
+      `.catch(() => {});
+      clearTaskCommands(taskId);
+      // No worktree cleanup (persistent); backend stays warm for the next turn.
+    }
+  }
+
+  // ─── Path B (warm ACP): goose / qwen warm backend (v2.6 Phase 2) ─────────────
+
+  // Warm ACP backends are per (chat, agent): each owns ONE stdio process + ACP
+  // connection + session. Pool key = chatId; the AgentPool's secondary key is the
+  // agent. This mirrors agent_sessions' (chat_id, agent) PK.
+  function getWarmAcpBackend(chatId: string, agent: string, installPath: string | null): WarmAcpBackend {
+    let backend = agentPool.get(chatId, agent);
+    if (!backend) {
+      backend = new WarmAcpBackend({
+        sql,
+        log,
+        chatId,
+        agent,
+        installPath,
+        resolved: getResolvedRegistry().get(agent),
+      });
+      agentPool.register(chatId, agent, backend);
+    }
+    return backend as WarmAcpBackend;
+  }
+
+  async function runWarmAcpTask(
+    task: {
+      id: string;
+      project_id: string;
+      input: string;
+      agent: string | null;
+      model: string | null;
+      mode_id: string | null;
+      thinking_option_id: string | null;
+      session_id: string | null;
+      chat_id: string | null;
+    },
+    installPath: string | null,
+  ): Promise<void> {
+    const taskId = task.id;
+    const agent = task.agent!;
+    // shouldUseWarmBackend guarantees both non-null before we get here.
+    const sessionId = task.session_id!;
+    const chatId = task.chat_id!;
+    log.info({ taskId, agent, chatId }, 'dispatcher: starting task (path B — warm ACP)');
+
+    const [project] = await sql<{ path: string | null }[]>`
+      SELECT path FROM projects WHERE id = ${task.project_id}
+    `;
+    const projectPath = project?.path;
+    if (!projectPath) {
+      await sql`
+        UPDATE tasks
+        SET state = 'failed', ended_at = clock_timestamp(), output_summary = 'Project has no path — cannot create worktree'
+        WHERE id = ${taskId}
+      `;
+      return;
+    }
+
+    const ac = new AbortController();
+
+    try {
+      await sql`
+        UPDATE tasks
+        SET state = 'running', started_at = clock_timestamp(), execution_path = 'acp'
+        WHERE id = ${taskId}
+      `;
+
+      // Persistent, session-keyed worktree (shared across turns + agents; NOT torn
+      // down per turn — Phase 3 reaps it). Same as the opencode-server path so a
+      // chat that switches opencode↔goose↔qwen shares one worktree.
+      const { worktreeId, worktreePath, baseCommit } = await ensureSessionWorktree(sql, projectPath, sessionId, {
+        signal: ac.signal,
+      });
+      log.info({ taskId, worktreePath }, 'dispatcher: session worktree ready (warm ACP)');
+
+      const [assistantMsg] = await sql<{ id: string }[]>`
+        INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+        VALUES (${sessionId}, ${chatId}, 'assistant', '', 'streaming', clock_timestamp())
+        RETURNING id
+      `;
+      const assistantId = assistantMsg!.id;
+
+      // write-edit-robustness #4: pre-turn checkpoint of the persistent session
+      // worktree (best-effort; never breaks dispatch). Same worktree the opencode
+      // path uses — a chat that switches opencode↔goose↔qwen shares one worktree.
+      await createCheckpoint(
+        sql,
+        { chatId, sessionId, worktreeId, worktreePath, messageId: assistantId },
+        { signal: ac.signal, log },
+      ).catch(() => null);
+
+      broker.publishFrame(sessionId, {
+        type: 'message_started',
+        message_id: assistantId,
+        chat_id: chatId,
+        role: 'assistant',
+      } as WsFrame);
+
+      const manifestCommands = getManifestCommands(agent);
+      if (manifestCommands.length > 0) {
+        setTaskCommands(taskId, manifestCommands);
+        broker.publishFrame(sessionId, {
+          type: 'agent_commands',
+          task_id: taskId,
+          session_id: sessionId,
+          commands: manifestCommands,
+        } as WsFrame);
+      }
+
+      // Accumulate the turn's stream for persistence + the final message content.
+      const textChunks: string[] = [];
+      const reasoningChunks: string[] = [];
+      const toolSnaps = new Map<string, AcpToolSnapshot>();
+
+      // Map transport-agnostic AgentEvents → the SAME WS frames the one-shot ACP
+      // path emits (identical to runOpenCodeServerTask's onEvent). No dcp stripping:
+      // that's an opencode-plugin artifact; goose/qwen don't emit dcp tags.
+      const onEvent = (e: AgentEvent): void => {
+        switch (e.type) {
+          case 'text':
+            textChunks.push(e.text);
+            broker.publishFrame(sessionId, {
+              type: 'delta',
+              message_id: assistantId,
+              chat_id: chatId,
+              content: e.text,
+            } as WsFrame);
+            break;
+          case 'reasoning':
+            reasoningChunks.push(e.text);
+            broker.publishFrame(sessionId, {
+              type: 'reasoning_delta',
+              message_id: assistantId,
+              chat_id: chatId,
+              content: e.text,
+            } as WsFrame);
+            break;
+          case 'tool_call':
+          case 'tool_update':
+            toolSnaps.set(e.toolCall.toolCallId, e.toolCall);
+            broker.publishFrame(sessionId, {
+              type: 'tool_call',
+              message_id: assistantId,
+              chat_id: chatId,
+              tool_call: snapshotToWireToolCall(e.toolCall),
+            } as WsFrame);
+            break;
+          case 'commands':
+            if (e.commands.length > 0) {
+              setTaskCommands(taskId, e.commands);
+              broker.publishFrame(sessionId, {
+                type: 'agent_commands',
+                task_id: taskId,
+                session_id: sessionId,
+                commands: e.commands,
+              } as WsFrame);
+            }
+            break;
+        }
+      };
+
+      const model = task.model ?? undefined;
+      const backend = getWarmAcpBackend(chatId, agent, installPath);
+      const handle = await backend.ensureSession(sessionId, {
+        agent,
+        model: model ?? '',
+        chatId,
+        worktreePath,
+        worktreeId,
+        projectId: task.project_id,
+      });
+      const result = await backend.prompt(handle, task.input, {
+        worktreePath,
+        model: model ?? '',
+        signal: ac.signal,
+        onEvent,
+        taskId,
+        modeId: task.mode_id ?? undefined,
+      });
+      // Phase 3: keep the pooled (chat,agent) backend warm across the turn.
+      agentPool.touch(chatId, agent);
+
+      const assistantContent = textChunks.join('').slice(0, 50_000);
+      const reasoningText = reasoningChunks.join('').slice(0, 200_000);
+      const outputSummary = (result.ok ? textChunks.join('') : result.error ?? 'warm ACP turn failed').slice(0, 500);
+
+      await persistExternalAgentTurn(sql, assistantId, [...toolSnaps.values()], reasoningText);
+
+      await sql`
+        UPDATE messages
+        SET content = ${assistantContent}, status = 'complete', finished_at = clock_timestamp()
+        WHERE id = ${assistantId}
+      `;
+      broker.publishFrame(sessionId, {
+        type: 'message_complete',
+        message_id: assistantId,
+        chat_id: chatId,
+      } as WsFrame);
+
+      if (stopping) {
+        await sql`UPDATE tasks SET state = 'cancelled', ended_at = clock_timestamp() WHERE id = ${taskId}`;
+        return; // worktree persists (no cleanup); backend stays warm
+      }
+
+      // Diff the persistent worktree against its captured baseline and SUPERSEDE
+      // the session's prior pending row (latest-wins) — identical to opencode.
+      const diff = await diffWorktree(worktreePath, projectPath, {
+        signal: ac.signal,
+        baseRef: baseCommit ?? 'HEAD',
+      });
+      if (diff) {
+        await sql`
+          DELETE FROM pending_changes WHERE session_id = ${sessionId} AND status = 'pending'
+        `;
+        await sql`
+          INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff, agent)
+          VALUES (${sessionId}, ${taskId}, ${projectPath}, 'edit', ${diff}, ${agent})
+        `;
+        log.info({ taskId, diffLength: diff.length }, 'dispatcher: diff superseded prior pending change (warm ACP)');
+      } else {
+        log.info({ taskId }, 'dispatcher: no changes detected in session worktree (warm ACP)');
+      }
+
+      // NO worktree cleanup — persistent (Phase 3 reaps it). Backend stays warm.
+
+      const [extCostRow] = await sql<{ total: number | null }[]>`
+        SELECT SUM(tokens_used)::int AS total
+        FROM messages
+        WHERE session_id = ${sessionId} AND tokens_used IS NOT NULL
+      `;
+      const extCostTokens = extCostRow?.total ?? null;
+
+      const finalState = result.ok ? 'completed' : 'failed';
+      await sql`
+        UPDATE tasks
+        SET state = ${finalState}, ended_at = clock_timestamp(), output_summary = ${outputSummary}, cost_tokens = ${extCostTokens}
+        WHERE id = ${taskId}
+      `;
+      log.info({ taskId, agent, finalState }, 'dispatcher: task finished (warm ACP)');
+      clearTaskCommands(taskId);
+    } catch (err) {
+      const errMsg = err instanceof Error ? err.message : String(err);
+      log.error({ taskId, agent, err: errMsg }, 'dispatcher: warm ACP error');
+      await sql`
+        UPDATE tasks
+        SET state = 'failed', ended_at = clock_timestamp(), output_summary = ${errMsg.slice(0, 500)}
+        WHERE id = ${taskId}
+      `.catch(() => {});
+      clearTaskCommands(taskId);
+      // No worktree cleanup (persistent); backend stays warm for the next turn.
+    }
+  }
+
   // ─── Helpers ────────────────────────────────────────────────────────────────
 
   async function waitForCompletion(assistantId: string): Promise<string> {
@@ -463,12 +1151,28 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
 
   return {
     start() {
-      log.info('dispatcher: starting poll loop');
+      log.info('dispatcher: starting poll loop + tasks_new listener');
-      timer = setInterval(() => {
+
-        poll().catch((err) => {
+      // Fallback poll — catches notifications missed while the listen connection
-          log.error({ err }, 'dispatcher: poll error');
+      // was down. The fast path is the NOTIFY listener below.
+      timer = setInterval(() => triggerPoll('interval'), POLL_INTERVAL_MS);
+
+      // Fast path: react immediately to new tasks. porsager reserves a dedicated
+      // connection and auto-resubscribes on reconnect; the onlisten callback
+      // fires on each (re)subscribe, so we kick a catch-up poll there too to
+      // sweep up anything inserted during a disconnect.
+      sql
+        .listen(
+          'tasks_new',
+          () => triggerPoll('notify'),
+          () => triggerPoll('listen-subscribed'),
+        )
+        .then((meta) => {
+          listener = meta;
+        })
+        .catch((err) => {
+          log.error({ err }, 'dispatcher: failed to LISTEN tasks_new — relying on poll fallback');
         });
-      }, POLL_INTERVAL_MS);
     },
 
     async stop() {
@@ -477,9 +1181,15 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         clearInterval(timer);
         timer = null;
       }
-      if (inflightPromise) {
+      if (listener) {
-        log.info('dispatcher: waiting for in-flight task');
+        await listener.unlisten().catch((err) => {
-        await inflightPromise;
+          log.error({ err }, 'dispatcher: unlisten error');
+        });
+        listener = null;
+      }
+      if (inflight.size > 0) {
+        log.info({ count: inflight.size }, 'dispatcher: waiting for in-flight tasks');
+        await Promise.allSettled([...inflight.values()]);
       }
       log.info('dispatcher: stopped');
     },

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

@@ -0,0 +1,271 @@
+// Fuzzy patch locator for staged edits.
+//
+// Local quantized models (qwen3.6 and friends) frequently reproduce an
+// `old_string` with small, semantically-irrelevant drift: trailing whitespace,
+// a different indent width, or "smart" unicode punctuation (curly quotes, an
+// en/em-dash, a non-breaking space) where the source has the plain ASCII form.
+// An exact `String.includes` then fails and the queued edit is lost even though
+// a human would say it obviously matches.
+//
+// `locateMatch` walks a ladder of progressively looser strategies and returns
+// the real `[start, end)` byte-offset span in the ORIGINAL content so the caller
+// can splice in `new_string` over the true file text (preserving the file's own
+// whitespace/unicode, not the model's drifted copy). The ladder stops at the
+// first strategy that resolves to a single span:
+//
+//   1. exact            — indexOf; >1 hit is reported `ambiguous` (we refuse to
+//                         guess which occurrence the model meant).
+//   2. per-line ws      — line-window compare ignoring per-line trailing
+//                         whitespace and leading/trailing blank needle lines.
+//   3. unicode canon    — same line-window compare after folding smart
+//                         punctuation to ASCII on both sides; the match is
+//                         mapped back to original offsets.
+//   4. levenshtein      — best line-window by normalized edit-distance
+//                         similarity; accepted only at >= SIMILARITY_THRESHOLD.
+//
+// Pure and dependency-free (Levenshtein is the standard iterative two-row DP),
+// reimplemented from the general technique — no vendored source.
+
+export type MatchResult =
+  | { kind: 'exact' | 'fuzzy'; start: number; end: number } // [start,end) offsets into content
+  | { kind: 'ambiguous'; count: number }
+  | { kind: 'not_found' };
+
+/** Levenshtein similarity floor for the final fuzzy fallback (strategy 4). */
+export const SIMILARITY_THRESHOLD = 0.66;
+
+export function locateMatch(content: string, needle: string): MatchResult {
+  // Empty needle has no meaningful match.
+  if (needle.length === 0) return { kind: 'not_found' };
+
+  // --- 1. Exact ----------------------------------------------------------------
+  const exact = locateExact(content, needle);
+  if (exact) return exact;
+
+  // --- 2. Per-line whitespace-insensitive -------------------------------------
+  const ws = locateByLineWindow(content, needle);
+  if (ws) return ws;
+
+  // --- 3. Unicode-canonicalized whitespace pass -------------------------------
+  const canon = locateCanonical(content, needle);
+  if (canon) return canon;
+
+  // --- 4. Levenshtein similarity ----------------------------------------------
+  const lev = locateByLevenshtein(content, needle);
+  if (lev) return lev;
+
+  return { kind: 'not_found' };
+}
+
+// --- Strategy 1: exact -------------------------------------------------------
+
+function locateExact(content: string, needle: string): MatchResult | null {
+  const first = content.indexOf(needle);
+  if (first === -1) return null;
+  const second = content.indexOf(needle, first + 1);
+  if (second === -1) {
+    return { kind: 'exact', start: first, end: first + needle.length };
+  }
+  // Count all occurrences so the caller can report a useful number.
+  let count = 2;
+  let idx = content.indexOf(needle, second + 1);
+  while (idx !== -1) {
+    count++;
+    idx = content.indexOf(needle, idx + 1);
+  }
+  return { kind: 'ambiguous', count };
+}
+
+// --- Line-window machinery ---------------------------------------------------
+
+interface Line {
+  /** Raw line text (no trailing newline). */
+  text: string;
+  /** Offset of the first char of this line in the original content. */
+  start: number;
+  /** Offset one past the last char of this line (before its newline, if any). */
+  end: number;
+}
+
+/**
+ * Split content into lines, tracking each line's real offset span. The span
+ * EXCLUDES the trailing newline so consecutive line spans plus their newlines
+ * exactly reconstruct the content; the match span we hand back covers from the
+ * first matched line's start through the last matched line's end (i.e. without a
+ * trailing newline), which is what an in-place splice wants.
+ */
+function splitLines(content: string): Line[] {
+  const lines: Line[] = [];
+  let start = 0;
+  for (let i = 0; i <= content.length; i++) {
+    if (i === content.length || content[i] === '\n') {
+      lines.push({ text: content.slice(start, i), start, end: i });
+      start = i + 1;
+    }
+  }
+  return lines;
+}
+
+/** Strip leading/trailing all-blank lines; returns the trimmed slice. */
+function trimBlankLines(lines: string[]): string[] {
+  let lo = 0;
+  let hi = lines.length;
+  while (lo < hi && lines[lo]!.trim() === '') lo++;
+  while (hi > lo && lines[hi - 1]!.trim() === '') hi--;
+  return lines.slice(lo, hi);
+}
+
+/**
+ * Find a contiguous window of content lines whose trailing-whitespace-trimmed
+ * text equals the needle's (blank-trimmed) lines. Returns the real offset span
+ * over the matched content lines, or null if zero match. Multiple matches →
+ * ambiguous. `normalize` lets the caller fold unicode before comparing.
+ */
+function locateByLineWindow(
+  content: string,
+  needle: string,
+  normalize: (s: string) => string = (s) => s,
+): MatchResult | null {
+  const contentLines = splitLines(content);
+  const needleLines = trimBlankLines(needle.split('\n'));
+  const n = needleLines.length;
+  if (n === 0) return null;
+  // A single needle line that is itself blank can't be located meaningfully.
+  if (n === 1 && needleLines[0]!.trim() === '') return null;
+
+  const needleKey = needleLines.map((l) => normalize(l.trimEnd())).join('\n');
+
+  const hits: Array<{ start: number; end: number }> = [];
+  for (let i = 0; i + n <= contentLines.length; i++) {
+    const windowKey = contentLines
+      .slice(i, i + n)
+      .map((l) => normalize(l.text.trimEnd()))
+      .join('\n');
+    if (windowKey === needleKey) {
+      hits.push({ start: contentLines[i]!.start, end: contentLines[i + n - 1]!.end });
+    }
+  }
+
+  if (hits.length === 0) return null;
+  if (hits.length > 1) return { kind: 'ambiguous', count: hits.length };
+  return { kind: 'fuzzy', start: hits[0]!.start, end: hits[0]!.end };
+}
+
+// --- Strategy 3: unicode canonicalization ------------------------------------
+
+/**
+ * Fold smart punctuation to its ASCII equivalent. Crucially this is a
+ * length-PRESERVING, per-character map (every replacement is one char → one
+ * char), so an offset into the canonical string is also a valid offset into the
+ * original — letting strategy 3 reuse the line-window matcher and still hand
+ * back true original-content offsets.
+ */
+function canonicalizeChar(ch: string): string {
+  switch (ch) {
+    // single quotes / apostrophes
+    case '‘': // '
+    case '’': // '
+    case '‚': // ‚
+    case '‛': // ‛
+      return "'";
+    // double quotes
+    case '“': // "
+    case '”': // "
+    case '„': // „
+    case '‟': // ‟
+      return '"';
+    // dashes
+    case '–': // – en dash
+    case '—': // — em dash
+    case '‒': // ‒ figure dash
+    case '―': // ― horizontal bar
+    case '−': // − minus sign
+      return '-';
+    // spaces
+    case ' ': // nbsp
+    case ' ': // figure space
+    case ' ': // narrow nbsp
+      return ' ';
+    default:
+      return ch;
+  }
+}
+
+function canonicalize(s: string): string {
+  let out = '';
+  for (const ch of s) out += canonicalizeChar(ch);
+  return out;
+}
+
+function locateCanonical(content: string, needle: string): MatchResult | null {
+  // Only worth running if canonicalization actually changes something on either
+  // side — otherwise it's identical to strategy 2 which already failed.
+  const canonContent = canonicalize(content);
+  const canonNeedle = canonicalize(needle);
+  if (canonContent === content && canonNeedle === needle) return null;
+  // Offsets are preserved (length-preserving fold), so a match on the canonical
+  // content maps directly back to the original.
+  return locateByLineWindow(canonContent, canonNeedle);
+}
+
+// --- Strategy 4: Levenshtein similarity --------------------------------------
+
+/** Standard iterative two-row Levenshtein edit distance. */
+function levenshtein(a: string, b: string): number {
+  if (a === b) return 0;
+  if (a.length === 0) return b.length;
+  if (b.length === 0) return a.length;
+
+  let prev = new Array<number>(b.length + 1);
+  let curr = new Array<number>(b.length + 1);
+  for (let j = 0; j <= b.length; j++) prev[j] = j;
+
+  for (let i = 1; i <= a.length; i++) {
+    curr[0] = i;
+    const ac = a.charCodeAt(i - 1);
+    for (let j = 1; j <= b.length; j++) {
+      const cost = ac === b.charCodeAt(j - 1) ? 0 : 1;
+      curr[j] = Math.min(
+        prev[j]! + 1, // deletion
+        curr[j - 1]! + 1, // insertion
+        prev[j - 1]! + cost, // substitution
+      );
+    }
+    [prev, curr] = [curr, prev];
+  }
+  return prev[b.length]!;
+}
+
+/** Normalized similarity in [0,1]: 1 - dist / max(len). */
+function similarity(a: string, b: string): number {
+  const maxLen = Math.max(a.length, b.length);
+  if (maxLen === 0) return 1;
+  return 1 - levenshtein(a, b) / maxLen;
+}
+
+function locateByLevenshtein(content: string, needle: string): MatchResult | null {
+  const contentLines = splitLines(content);
+  const needleLines = trimBlankLines(needle.split('\n'));
+  const n = needleLines.length;
+  if (n === 0) return null;
+  if (contentLines.length < n) return null;
+
+  const needleJoined = needleLines.map((l) => l.trim()).join('\n');
+
+  let best = -1;
+  let bestSpan: { start: number; end: number } | null = null;
+  for (let i = 0; i + n <= contentLines.length; i++) {
+    const window = contentLines.slice(i, i + n);
+    const windowJoined = window.map((l) => l.text.trim()).join('\n');
+    const score = similarity(windowJoined, needleJoined);
+    if (score > best) {
+      best = score;
+      bestSpan = { start: window[0]!.start, end: window[n - 1]!.end };
+    }
+  }
+
+  if (bestSpan && best >= SIMILARITY_THRESHOLD) {
+    return { kind: 'fuzzy', start: bestSpan.start, end: bestSpan.end };
+  }
+  return null;
+}

apps/coder/src/services/orphan-worktree-reaper.ts

@@ -0,0 +1,170 @@
+/**
+ * v2.6 Phase 3 (3.4) — orphan worktree reaper.
+ *
+ * Reclaims on-disk session worktree dirs under WORKTREE_BASE that have NO live
+ * (`status='active'`) row in the `worktrees` table — leaks from a crash between
+ * `git worktree add` and the DB insert, a missed chat-close hook, or a manual rm
+ * of the DB row. Extends the periodic-sweeper pattern (apps/server's truncation +
+ * stale-streaming reaper).
+ *
+ * SAFETY (Paseo worktree-archive cascade + superset destroy-saga lift): before
+ * removing ANY dir, run `checkWorktreeWorkAtRisk` — a dirty / unpushed / unmerged
+ * worktree is SKIPPED (logged), never force-removed. The pure orphan-target
+ * selection (which dirs are candidates) lives in
+ * `backends/lifecycle-decisions.ts:selectOrphanWorktreeTargets` and is unit-tested;
+ * this module does the DB read + fs stat + git preflight + removal side-effects.
+ *
+ * The mtime grace (default 1h) means a dir mid-`ensureSessionWorktree` (created on
+ * disk, row not yet committed) is never swept — the grace window covers the gap.
+ */
+import { readdir, stat } from 'node:fs/promises';
+import { join } from 'node:path';
+import type { FastifyBaseLogger } from 'fastify';
+import type { Sql } from '../db.js';
+import { WORKTREE_BASE, checkWorktreeWorkAtRisk } from './worktrees.js';
+import { hostExec } from './host-exec.js';
+import {
+  selectOrphanWorktreeTargets,
+  DEFAULT_ORPHAN_WORKTREE_GRACE_MS,
+} from './backends/lifecycle-decisions.js';
+
+export interface OrphanWorktreeReaperDeps {
+  sql: Sql;
+  log: FastifyBaseLogger;
+  intervalMs: number;
+  graceMs?: number;
+}
+
+export interface OrphanReaperResult {
+  scanned: number;
+  candidates: number;
+  reaped: string[];
+  skippedAtRisk: string[];
+}
+
+/** Single-pass reap: select orphan candidates, preflight at-risk, remove the safe. */
+export async function reapOrphanWorktrees(
+  sql: Sql,
+  log: FastifyBaseLogger,
+  graceMs: number = DEFAULT_ORPHAN_WORKTREE_GRACE_MS,
+  now: number = Date.now(),
+): Promise<OrphanReaperResult> {
+  // Enumerate on-disk session worktree dirs (`sess-*`). Per-task worktrees
+  // (arena/new_task/MCP) are cleaned up inline by the one-shot path, so we only
+  // own the persistent session dirs the warm paths leave behind.
+  let dirents: string[];
+  try {
+    dirents = await readdir(WORKTREE_BASE);
+  } catch {
+    return { scanned: 0, candidates: 0, reaped: [], skippedAtRisk: [] }; // base absent → nothing to do
+  }
+  const onDisk: { path: string; mtimeMs: number }[] = [];
+  for (const name of dirents) {
+    if (!name.startsWith('sess-')) continue; // only persistent session worktrees
+    const path = join(WORKTREE_BASE, name);
+    try {
+      const s = await stat(path);
+      if (!s.isDirectory()) continue;
+      onDisk.push({ path, mtimeMs: s.mtimeMs });
+    } catch {
+      // vanished between readdir and stat — skip
+    }
+  }
+
+  // Live worktree paths from the DB (active rows only — archived/removed rows are
+  // not "live", so their leftover dirs are reapable orphans).
+  const liveRows = await sql<{ path: string }[]>`
+    SELECT path FROM worktrees WHERE status = 'active'
+  `;
+  const live = new Set(liveRows.map((r) => r.path));
+
+  const candidates = selectOrphanWorktreeTargets(onDisk, live, now, graceMs);
+  const reaped: string[] = [];
+  const skippedAtRisk: string[] = [];
+
+  for (const path of candidates) {
+    // Preflight: never reap work at risk. A git error forces atRisk=true (fail
+    // closed), so a half-broken worktree is kept, not silently destroyed.
+    const risk = await checkWorktreeWorkAtRisk(path);
+    if (risk.atRisk) {
+      skippedAtRisk.push(path);
+      log.warn({ path, dirty: risk.dirty, unmerged: risk.unmerged, error: risk.error }, 'orphan-reaper: skipping at-risk orphan worktree');
+      continue;
+    }
+    const removed = await removeOrphanDir(path);
+    if (removed) reaped.push(path);
+  }
+
+  if (reaped.length > 0 || skippedAtRisk.length > 0) {
+    log.info({ scanned: onDisk.length, candidates: candidates.length, reaped, skippedAtRisk }, 'orphan-reaper: pass complete');
+  }
+  return { scanned: onDisk.length, candidates: candidates.length, reaped, skippedAtRisk };
+}
+
+/**
+ * Remove a single orphan worktree dir. Resolve its main repo via the git
+ * common-dir, run `worktree remove --force` from there + prune, then rm the dir as
+ * a backstop. Best-effort: every step is independently fault-tolerant so a partial
+ * state (dir present, git untracked) still gets reclaimed.
+ */
+async function removeOrphanDir(path: string): Promise<boolean> {
+  // Find the owning repo (the common git dir's parent). When the dir isn't a valid
+  // worktree anymore, this fails and we fall back to a plain rm.
+  const common = await hostExec(
+    `git -C ${shellEscape(path)} rev-parse --path-format=absolute --git-common-dir`,
+    { timeoutMs: 10_000 },
+  ).catch(() => null);
+  const commonDir = common && common.exitCode === 0 ? common.stdout.trim() : '';
+  // The repo worktree root is the parent of the .git common dir (strip trailing /.git).
+  const repoRoot = commonDir.replace(/\/\.git\/?$/, '').replace(/\/\.git$/, '');
+
+  if (repoRoot && repoRoot !== commonDir) {
+    await hostExec(
+      `git -C ${shellEscape(repoRoot)} worktree remove ${shellEscape(path)} --force`,
+      { timeoutMs: 15_000 },
+    ).catch(() => {});
+    await hostExec(
+      `git -C ${shellEscape(repoRoot)} worktree prune`,
+      { timeoutMs: 10_000 },
+    ).catch(() => {});
+  }
+  // Backstop: ensure the dir is gone even if the git remove no-op'd.
+  const rm = await hostExec(`rm -rf ${shellEscape(path)}`, { timeoutMs: 15_000 }).catch(() => null);
+  return rm != null && rm.exitCode === 0;
+}
+
+/** Minimal single-quote shell escape (mirrors worktrees.ts). */
+function shellEscape(s: string): string {
+  return "'" + s.replace(/'/g, "'\\''") + "'";
+}
+
+/** Periodic orphan-worktree reaper, started/stopped by the bootstrap. Unref'd. */
+export function createOrphanWorktreeReaper(deps: OrphanWorktreeReaperDeps): { start(): void; stop(): void } {
+  const { sql, log, intervalMs } = deps;
+  const graceMs = deps.graceMs ?? DEFAULT_ORPHAN_WORKTREE_GRACE_MS;
+  let timer: ReturnType<typeof setInterval> | null = null;
+  let running = false;
+
+  return {
+    start() {
+      if (timer) return;
+      timer = setInterval(() => {
+        if (running) return; // a slow pass must not overlap the next tick
+        running = true;
+        void reapOrphanWorktrees(sql, log, graceMs)
+          .catch((err) => log.warn({ err: err instanceof Error ? err.message : String(err) }, 'orphan-reaper: pass error'))
+          .finally(() => {
+            running = false;
+          });
+      }, intervalMs);
+      timer.unref?.();
+      log.info({ intervalMs, graceMs }, 'orphan-reaper: started');
+    },
+    stop() {
+      if (timer) {
+        clearInterval(timer);
+        timer = null;
+      }
+    },
+  };
+}

apps/coder/src/services/pending_changes.ts

@@ -2,6 +2,7 @@ import { readFile, writeFile, unlink, mkdir } from 'node:fs/promises';
 import { dirname } from 'node:path';
 import type { Sql } from '../db.js';
 import { resolveWritePath } from './write_guard.js';
+import { locateMatch } from './fuzzy-match.js';
 
 // --- Types -------------------------------------------------------------------
 
@@ -13,6 +14,10 @@ export interface PendingChange {
   operation: 'create' | 'edit' | 'delete';
   diff: string;
   status: 'pending' | 'applied' | 'rejected' | 'reverted';
+  // v2.6 Phase 1-UX: which agent staged this change (DiffPanel attribution).
+  // Native boocode write tools stamp 'boocode'; the manual RightRail create path
+  // passes null (renders as "manual"). NULL on legacy rows queued pre-v2.6.
+  agent: string | null;
   created_at: string;
 }
 
@@ -34,13 +39,17 @@ export async function queueEdit(
   oldString: string,
   newString: string,
   projectRoot: string,
+  // v2.6 Phase 1-UX: attribution. Defaults to 'boocode' because the only callers
+  // that omit it are the native write tools (edit_file/create_file/delete_file).
+  // Pass null explicitly for the manual RightRail create path.
+  agent: string | null = 'boocode',
 ): Promise<PendingChange> {
   const resolved = resolveWritePath(projectRoot, filePath);
   const diff = JSON.stringify({ old: oldString, new: newString });
 
   const [row] = await sql<PendingChange[]>`
-    INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff)
+    INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff, agent)
-    VALUES (${sessionId}, ${taskId}, ${resolved}, 'edit', ${diff})
+    VALUES (${sessionId}, ${taskId}, ${resolved}, 'edit', ${diff}, ${agent})
     RETURNING *
   `;
   return row!;
@@ -53,12 +62,15 @@ export async function queueCreate(
   filePath: string,
   content: string,
   projectRoot: string,
+  // See queueEdit: defaults to 'boocode' for the native write tools; the manual
+  // RightRail create route passes null.
+  agent: string | null = 'boocode',
 ): Promise<PendingChange> {
   const resolved = resolveWritePath(projectRoot, filePath);
 
   const [row] = await sql<PendingChange[]>`
-    INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff)
+    INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff, agent)
-    VALUES (${sessionId}, ${taskId}, ${resolved}, 'create', ${content})
+    VALUES (${sessionId}, ${taskId}, ${resolved}, 'create', ${content}, ${agent})
     RETURNING *
   `;
   return row!;
@@ -70,12 +82,14 @@ export async function queueDelete(
   taskId: string | null,
   filePath: string,
   projectRoot: string,
+  // See queueEdit: defaults to 'boocode' for the native write tools.
+  agent: string | null = 'boocode',
 ): Promise<PendingChange> {
   const resolved = resolveWritePath(projectRoot, filePath);
 
   const [row] = await sql<PendingChange[]>`
-    INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff)
+    INSERT INTO pending_changes (session_id, task_id, file_path, operation, diff, agent)
-    VALUES (${sessionId}, ${taskId}, ${resolved}, 'delete', '')
+    VALUES (${sessionId}, ${taskId}, ${resolved}, 'delete', '', ${agent})
     RETURNING *
   `;
   return row!;
@@ -108,10 +122,18 @@ export async function applyOne(
       case 'edit': {
         const { old: oldStr, new: newStr } = JSON.parse(change.diff) as { old: string; new: string };
         const content = await readFile(change.file_path, 'utf8');
-        if (!content.includes(oldStr)) {
+        const match = locateMatch(content, oldStr);
-          throw new Error('old_string not found in file — file may have changed since the edit was queued');
+        if (match.kind === 'ambiguous') {
+          throw new Error(
+            `old_string matches ${match.count} locations — add surrounding context to disambiguate`,
+          );
         }
-        const updated = content.replace(oldStr, newStr);
+        if (match.kind === 'not_found') {
+          throw new Error(
+            'old_string not found in file (even fuzzily) — file may have changed since the edit was queued',
+          );
+        }
+        const updated = content.slice(0, match.start) + newStr + content.slice(match.end);
         await writeFile(change.file_path, updated, 'utf8');
         break;
       }
@@ -190,10 +212,18 @@ export async function rewindOne(
         // Reverse an edit: swap old and new
         const { old: oldStr, new: newStr } = JSON.parse(change.diff) as { old: string; new: string };
         const content = await readFile(change.file_path, 'utf8');
-        if (!content.includes(newStr)) {
+        const match = locateMatch(content, newStr);
-          throw new Error('new_string not found in file — cannot rewind; file may have been modified since apply');
+        if (match.kind === 'ambiguous') {
+          throw new Error(
+            `new_string matches ${match.count} locations — cannot rewind; add surrounding context to disambiguate`,
+          );
         }
-        const reverted = content.replace(newStr, oldStr);
+        if (match.kind === 'not_found') {
+          throw new Error(
+            'new_string not found in file (even fuzzily) — cannot rewind; file may have been modified since apply',
+          );
+        }
+        const reverted = content.slice(0, match.start) + oldStr + content.slice(match.end);
         await writeFile(change.file_path, reverted, 'utf8');
         break;
       }

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

@@ -27,13 +27,6 @@ const OPENCODE_COMMANDS: AgentCommand[] = [
   { name: 'export', description: 'Export session' },
 ];
 
-const CURSOR_COMMANDS: AgentCommand[] = [
-  { name: 'help', description: 'Show available slash commands' },
-  { name: 'clear', description: 'Clear conversation' },
-  { name: 'compact', description: 'Compact context' },
-  { name: 'resume', description: 'Resume a prior session' },
-];
-
 const GOOSE_COMMANDS: AgentCommand[] = [
   { name: 'help', description: 'Show available commands' },
   { name: 'clear', description: 'Clear conversation' },
@@ -49,23 +42,12 @@ const QWEN_COMMANDS: AgentCommand[] = [
   { name: 'review', description: 'Review changes' },
 ];
 
-const COPILOT_COMMANDS: AgentCommand[] = [
-  { name: 'help', description: 'Show available commands' },
-  { name: 'explain', description: 'Explain selected code' },
-  { name: 'fix', description: 'Fix issues in context' },
-  { name: 'tests', description: 'Generate or run tests' },
-  { name: 'doc', description: 'Generate documentation' },
-  { name: 'clear', description: 'Clear conversation' },
-];
-
 /** boocode harness uses /api/skills — merged on the frontend. */
 export const PROVIDER_COMMANDS: Record<string, AgentCommand[]> = {
   claude: CLAUDE_COMMANDS,
   opencode: OPENCODE_COMMANDS,
-  cursor: CURSOR_COMMANDS,
   goose: GOOSE_COMMANDS,
   qwen: QWEN_COMMANDS,
-  copilot: COPILOT_COMMANDS,
   boocode: [],
 };
 

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

@@ -0,0 +1,133 @@
+/**
+ * v2.3 resolved provider registry — single in-memory source of truth after
+ * merging the hardcoded built-ins (provider-registry.ts) with the config file
+ * (provider-config.ts). Mirrors Paseo's buildProviderRegistry/addDerivedProviders.
+ *
+ * Phase 1 scope: build + expose the resolved registry. `launchCommand` is null
+ * for built-ins (the default argv is resolved at dispatch time in Phase 3) and
+ * is the config `command` for custom ACP entries. No DB columns (design.md §3.3);
+ * `enabled` lives in memory only.
+ */
+import type { ProviderDef } from './provider-registry.js';
+import { PROVIDERS } from './provider-registry.js';
+import { load, type CoderProvidersFile } from './provider-config.js';
+
+export interface ResolvedProviderDef extends ProviderDef {
+  id: string;
+  enabled: boolean;
+  isBuiltin: boolean;
+  isCustomAcp: boolean;
+  /** Full argv for spawn: [binary, ...args]. Null for built-ins (resolved at dispatch). */
+  launchCommand: [string, ...string[]] | null;
+  env: Record<string, string> | undefined;
+  configLabel?: string;
+  configDescription?: string;
+  /** Config `models` — REPLACES the discovered/static model list when present. */
+  configModels?: Array<{ id: string; label: string }>;
+  /** Config `additionalModels` — MERGED on top of the resolved model list. */
+  configAdditionalModels?: Array<{ id: string; label: string }>;
+}
+
+/**
+ * Merge built-ins with config overrides into the resolved registry.
+ * Algorithm verbatim from design.md §3.1.
+ */
+export function buildResolvedRegistry(
+  builtins: ProviderDef[],
+  config: CoderProvidersFile,
+): Map<string, ResolvedProviderDef> {
+  const out = new Map<string, ResolvedProviderDef>();
+  const overrides = config.providers ?? {};
+  const builtinNames = new Set(builtins.map((b) => b.name));
+
+  // 1. Built-ins, applying a config override if one is present.
+  for (const def of builtins) {
+    const ov = overrides[def.name];
+    let enabled = ov?.enabled !== false;
+
+    // 3. boocode is always enabled; an enabled:false override is ignored + warned.
+    if (def.name === 'boocode' && ov?.enabled === false) {
+      console.warn("provider-config: ignoring enabled:false for built-in 'boocode' (always enabled)");
+      enabled = true;
+    }
+
+    const launchCommand =
+      ov?.command && ov.command.length > 0 ? (ov.command as [string, ...string[]]) : null;
+
+    out.set(def.name, {
+      ...def,
+      label: ov?.label ?? def.label,
+      id: def.name,
+      enabled,
+      isBuiltin: true,
+      isCustomAcp: false,
+      launchCommand,
+      env: ov?.env,
+      configLabel: ov?.label,
+      configDescription: ov?.description,
+      configModels: ov?.models,
+      configAdditionalModels: ov?.additionalModels,
+    });
+  }
+
+  // 2. Config ids that are not built-ins → custom ACP entries.
+  for (const [id, ov] of Object.entries(overrides)) {
+    if (builtinNames.has(id)) continue;
+    // §2.2 rules: "New id without extends → Reject at load with log."
+    if (ov.extends !== 'acp' || !ov.label || !ov.command || ov.command.length === 0) {
+      console.warn(
+        `provider-config: skipping custom provider '${id}' — requires extends:'acp', label, and command`,
+      );
+      continue;
+    }
+    out.set(id, {
+      name: id,
+      label: ov.label,
+      transport: 'acp',
+      modelSource: 'probe',
+      id,
+      enabled: ov.enabled !== false,
+      isBuiltin: false,
+      isCustomAcp: true,
+      launchCommand: ov.command as [string, ...string[]],
+      env: ov.env,
+      configLabel: ov.label,
+      configDescription: ov.description,
+      configModels: ov.models,
+      configAdditionalModels: ov.additionalModels,
+    });
+  }
+
+  return out;
+}
+
+// --- Module singleton ---------------------------------------------------------
+
+let cachedRegistry: Map<string, ResolvedProviderDef> | null = null;
+let cachedPath: string | null = null;
+
+/** Load the config file at `path`, rebuild, and cache the resolved registry. */
+export function loadProviderConfig(path: string): Map<string, ResolvedProviderDef> {
+  cachedPath = path;
+  cachedRegistry = buildResolvedRegistry(PROVIDERS, load(path));
+  return cachedRegistry;
+}
+
+/** Re-read the last-loaded config file and rebuild (Phase 4 calls this after PATCH). */
+export function reloadProviderConfig(): Map<string, ResolvedProviderDef> {
+  if (cachedPath == null) {
+    cachedRegistry = buildResolvedRegistry(PROVIDERS, { providers: {} });
+    return cachedRegistry;
+  }
+  return loadProviderConfig(cachedPath);
+}
+
+/** The cached resolved registry (built-ins only if nothing has been loaded yet). */
+export function getResolvedRegistry(): Map<string, ResolvedProviderDef> {
+  return cachedRegistry ?? buildResolvedRegistry(PROVIDERS, { providers: {} });
+}
+
+/** Resolved provider ids in registry order. */
+export function getResolvedProviderIds(): string[] {
+  return [...getResolvedRegistry().keys()];
+}

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

@@ -0,0 +1,100 @@
+/**
+ * v2.3 provider config file (`/data/coder-providers.json`) — schema + loader.
+ *
+ * Layers config-backed overrides/custom-ACP entries over the hardcoded built-ins
+ * (see provider-config-registry.ts). Loading NEVER throws at startup (design.md
+ * §2.1): a missing file, invalid JSON, or schema mismatch all fall back to
+ * `{ providers: {} }` (built-ins only, all enabled).
+ */
+import { readFileSync, writeFileSync } from 'node:fs';
+import { z } from 'zod';
+
+// Schemas verbatim from design.md §2.2.
+export const ProviderOverrideSchema = z.object({
+  extends: z.enum(['acp']).optional(), // v2.3: only 'acp' for custom; built-ins omit extends
+  label: z.string().min(1).optional(),
+  description: z.string().optional(),
+  command: z.array(z.string().min(1)).min(1).optional(), // [binary, ...args]
+  env: z.record(z.string()).optional(),
+  enabled: z.boolean().optional(), // default true
+  order: z.number().int().optional(), // UI sort key
+  models: z.array(z.object({ id: z.string(), label: z.string() })).optional(),
+  additionalModels: z.array(z.object({ id: z.string(), label: z.string() })).optional(),
+});
+
+export const CoderProvidersFileSchema = z.object({
+  providers: z.record(ProviderOverrideSchema).default({}),
+});
+
+export type ProviderOverride = z.infer<typeof ProviderOverrideSchema>;
+export type CoderProvidersFile = z.infer<typeof CoderProvidersFileSchema>;
+
+/**
+ * PATCH body schema (design.md §6.2). A partial providers map where each value
+ * is either a full override object (REPLACES that id's override) or `null`
+ * (DELETES the override → revert to the built-in default). Ids absent from the
+ * patch are left untouched. The route validates the body against this first
+ * (malformed → 422) so a bad shape can never reach the merge/save step.
+ */
+export const ProviderConfigPatchSchema = z.object({
+  providers: z.record(ProviderOverrideSchema.nullable()).default({}),
+});
+
+export type ProviderConfigPatch = z.infer<typeof ProviderConfigPatchSchema>;
+
+/**
+ * Shallow per-id merge (design.md §6.2 / Paseo `patchConfig`). Each key in
+ * `patch.providers` REPLACES that id's override object wholesale (NOT a deep
+ * field merge); a `null` value DELETES the override. Returns a new object —
+ * never mutates `current`. The result is a plain CoderProvidersFile (no nulls),
+ * which the route re-validates against CoderProvidersFileSchema before save.
+ */
+export function mergeProviderConfigPatch(
+  current: CoderProvidersFile,
+  patch: ProviderConfigPatch,
+): CoderProvidersFile {
+  const providers: Record<string, ProviderOverride> = { ...current.providers };
+  for (const [id, override] of Object.entries(patch.providers)) {
+    if (override === null) {
+      delete providers[id];
+    } else {
+      providers[id] = override;
+    }
+  }
+  return { providers };
+}
+
+/** Read + parse + validate. Falls back to built-ins-only on any failure; never throws. */
+export function load(path: string): CoderProvidersFile {
+  let raw: string;
+  try {
+    raw = readFileSync(path, 'utf8');
+  } catch {
+    // Missing file → built-ins only. Expected, not an error.
+    return { providers: {} };
+  }
+
+  let json: unknown;
+  try {
+    json = JSON.parse(raw);
+  } catch (err) {
+    console.error(`provider-config: invalid JSON in ${path} — using built-ins only`, err);
+    return { providers: {} };
+  }
+
+  const parsed = CoderProvidersFileSchema.safeParse(json);
+  if (!parsed.success) {
+    console.error(
+      `provider-config: schema validation failed for ${path} — using built-ins only`,
+      parsed.error.flatten(),
+    );
+    return { providers: {} };
+  }
+
+  return parsed.data;
+}
+
+/** Write the config back to disk (used by the Phase 4 PATCH route). */
+export function save(path: string, config: CoderProvidersFile): void {
+  writeFileSync(path, `${JSON.stringify(config, null, 2)}\n`, 'utf8');
+}

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

@@ -0,0 +1,71 @@
+/**
+ * v2.3 Phase 4 (design.md §8) — per-provider plaintext diagnostic report.
+ *
+ * Read-only by default: reports CACHED state (resolved registry def + the
+ * available_agents row + the warm snapshot-cache entry) plus a `which`-style
+ * PATH check for the launch binary. It does NOT spawn an ACP probe — §8 lists
+ * the live initialize probe as optional, and the route defaults to cached state.
+ *
+ * A template string is the whole formatter (no Paseo diagnostic-utils port).
+ */
+import type { ResolvedProviderDef } from './provider-config-registry.js';
+import type { ProviderSnapshotEntry, ProviderModel } from './provider-types.js';
+import { isCommandAvailable } from './command-availability.js';
+
+/** The subset of an `available_agents` row the diagnostic reads. */
+export interface DiagnosticAgentRow {
+  name: string;
+  install_path: string | null;
+  supports_acp?: boolean;
+  models?: ProviderModel[] | null;
+  last_probed_at?: string | Date | null;
+}
+
+interface DiagnosticOpts {
+  /** Warm snapshot-cache entry (read-only peek) — source of the last probe error. */
+  cachedEntry?: ProviderSnapshotEntry;
+  /** Injectable PATH check (defaults to the real `which`); stubbed in tests. */
+  checkAvailable?: (binary: string) => Promise<boolean>;
+}
+
+/** Resolve the binary the dispatcher would launch (for the PATH check + report). */
+function resolveBinary(resolved: ResolvedProviderDef, agentRow: DiagnosticAgentRow | undefined): string {
+  return resolved.launchCommand?.[0] ?? agentRow?.install_path ?? resolved.id;
+}
+
+export async function getProviderDiagnostic(
+  resolved: ResolvedProviderDef,
+  agentRow: DiagnosticAgentRow | undefined,
+  opts: DiagnosticOpts = {},
+): Promise<string> {
+  const checkAvailable = opts.checkAvailable ?? isCommandAvailable;
+  const installed = agentRow?.install_path != null;
+  const binary = resolveBinary(resolved, agentRow);
+  // boocode is native (no binary to launch) — short-circuit the PATH check.
+  const commandAvailable = resolved.transport === 'native' ? true : await checkAvailable(binary);
+  const lastProbedAt =
+    agentRow?.last_probed_at != null ? new Date(agentRow.last_probed_at).toISOString() : '(never)';
+  const modelCount = agentRow?.models?.length ?? 0;
+  const launchCommand = resolved.launchCommand
+    ? resolved.launchCommand.join(' ')
+    : '(built-in default, resolved at dispatch)';
+  const lastError = opts.cachedEntry?.error ?? '(none recorded)';
+
+  return [
+    `provider: ${resolved.id}`,
+    `label: ${resolved.configLabel ?? resolved.label}`,
+    `transport: ${resolved.transport}`,
+    `enabled: ${resolved.enabled}`,
+    `builtin: ${resolved.isBuiltin}`,
+    `customAcp: ${resolved.isCustomAcp}`,
+    `installed: ${installed}`,
+    `install_path: ${agentRow?.install_path ?? '(none)'}`,
+    `binary: ${binary}`,
+    `command_available: ${commandAvailable}`,
+    `launch_command: ${launchCommand}`,
+    `supports_acp: ${agentRow?.supports_acp ?? '(unknown)'}`,
+    `last_probed_at: ${lastProbedAt}`,
+    `models_in_db: ${modelCount}`,
+    `last_probe_error: ${lastError}`,
+  ].join('\n');
+}

apps/coder/src/services/provider-manifest.ts

@@ -24,31 +24,6 @@ const OPENCODE_MODES: ProviderMode[] = [
   { id: 'full-access', label: 'Full Access', description: 'Auto-approves all tool prompts', isUnattended: true },
 ];
 
-const COPILOT_MODES: ProviderMode[] = [
-  {
-    id: 'https://agentclientprotocol.com/protocol/session-modes#agent',
-    label: 'Agent',
-    description: 'Default agent mode',
-  },
-  {
-    id: 'https://agentclientprotocol.com/protocol/session-modes#plan',
-    label: 'Plan',
-    description: 'Plan mode for multi-step work',
-  },
-  {
-    id: 'allow-all',
-    label: 'Allow All',
-    description: 'Automatically approves all tool, path, and URL requests',
-    isUnattended: true,
-  },
-];
-
-const CURSOR_CLI_MODES: ProviderMode[] = [
-  { id: 'agent', label: 'Agent', description: 'Full agent capabilities with tool access' },
-  { id: 'plan', label: 'Plan', description: 'Read-only planning mode' },
-  { id: 'ask', label: 'Ask', description: 'Q&A read-only mode' },
-];
-
 const QWEN_PTY_MODES: ProviderMode[] = [
   { id: 'default', label: 'Default', description: 'Prompt for approval' },
   { id: 'plan', label: 'Plan', description: 'Plan only — no edits' },
@@ -75,14 +50,6 @@ export const PROVIDER_MANIFEST: Record<string, ProviderManifestEntry> = {
     defaultModeId: 'build',
     modes: OPENCODE_MODES,
   },
-  copilot: {
-    defaultModeId: 'https://agentclientprotocol.com/protocol/session-modes#agent',
-    modes: COPILOT_MODES,
-  },
-  cursor: {
-    defaultModeId: 'agent',
-    modes: CURSOR_CLI_MODES,
-  },
   goose: {
     defaultModeId: null,
     modes: [],

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

@@ -13,8 +13,7 @@ export interface ProviderDef {
  * - boocode: llama-swap only
  * - opencode: ACP probe + mergeLlamaSwap (prefixed llama-swap/* ids)
  * - qwen: ACP probe + merge ~/.qwen/settings.json; PTY fallback reads settings only
- * - cursor: ACP probe + cursor-agent models CLI fallback
+ * - goose: ACP probe only
- * - goose / copilot: ACP probe only
  * - claude: static manifest models + thinking options
  */
 export const PROVIDERS: ProviderDef[] = [
@@ -24,12 +23,6 @@ export const PROVIDERS: ProviderDef[] = [
     transport: 'native',
     modelSource: 'llama-swap',
   },
-  {
-    name: 'cursor',
-    label: 'Cursor Agent',
-    transport: 'acp',
-    modelSource: 'probe',
-  },
   {
     name: 'opencode',
     label: 'OpenCode',
@@ -48,9 +41,18 @@ export const PROVIDERS: ProviderDef[] = [
     label: 'Claude Code',
     transport: 'pty',
     modelSource: 'static',
+    // Passed verbatim to `claude --model <id>` (PTY dispatch). The CLI accepts a
+    // latest-alias ('opus'/'sonnet'/'haiku') or a pinned full name
+    // ('claude-opus-4-8'). Aliases never go stale; pinned IDs let you select an
+    // exact version. Extend/replace per-install via data/coder-providers.json
+    // (models / additionalModels) without a code change.
     staticModels: [
-      { id: 'claude-opus-4-20250514', label: 'Opus 4' },
+      { id: 'opus', label: 'Opus (latest)' },
-      { id: 'claude-sonnet-4-20250514', label: 'Sonnet 4' },
+      { id: 'claude-opus-4-8', label: 'Opus 4.8' },
+      { id: 'sonnet', label: 'Sonnet (latest)' },
+      { id: 'claude-sonnet-4-6', label: 'Sonnet 4.6' },
+      { id: 'haiku', label: 'Haiku (latest)' },
+      { id: 'claude-haiku-4-5-20251001', label: 'Haiku 4.5' },
     ],
   },
   {
@@ -59,12 +61,6 @@ export const PROVIDERS: ProviderDef[] = [
     transport: 'acp',
     modelSource: 'probe',
   },
-  {
-    name: 'copilot',
-    label: 'GitHub Copilot',
-    transport: 'acp',
-    modelSource: 'probe',
-  },
 ];
 
 export const PROVIDERS_BY_NAME = new Map(PROVIDERS.map((p) => [p.name, p]));

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

@@ -2,35 +2,34 @@
  * Provider snapshot cache — cold ACP probe per provider + static manifest merge.
  */
 import { homedir } from 'node:os';
-import { exec as execCb } from 'node:child_process';
-import { promisify } from 'node:util';
 import type { FastifyBaseLogger } from 'fastify';
 import type { Sql } from '../db.js';
 import type { Config } from '../config.js';
-import { PROVIDERS, type ProviderDef } from './provider-registry.js';
 import {
   getManifestDefaultModeId,
   getManifestModes,
   PROVIDER_MANIFEST,
 } from './provider-manifest.js';
 import { probeAcpProvider } from './acp-probe.js';
-import { parseCursorAgentModelsOutput } from './cursor-models.js';
+import type { ProviderModel, ProviderSnapshotEntry, AgentCommand } from './provider-types.js';
-import type { ProviderModel, ProviderSnapshotEntry } from './provider-types.js';
 import { getManifestCommands, mergeCommands } from './provider-commands.js';
 import { readQwenSettingsModels } from './qwen-settings.js';
-
+import { getResolvedRegistry, type ResolvedProviderDef } from './provider-config-registry.js';
-const exec = promisify(execCb);
+import { isCommandAvailable } from './command-availability.js';
+import { discoverClaudeCommands } from './claude-command-discovery.js';
 
 interface AgentRow {
   name: string;
   install_path: string | null;
   supports_acp: boolean;
   models: ProviderModel[] | null;
+  commands: AgentCommand[] | null;
   label: string | null;
   transport: string | null;
+  last_probed_at: string | Date | null;
 }
 
-async function fetchLlamaSwapModels(config: Config): Promise<ProviderModel[]> {
+export async function fetchLlamaSwapModels(config: Config): Promise<ProviderModel[]> {
   try {
     const res = await fetch(`${config.LLAMA_SWAP_URL}/v1/models`);
     if (!res.ok) return [];
@@ -41,15 +40,6 @@ async function fetchLlamaSwapModels(config: Config): Promise<ProviderModel[]> {
   }
 }
 
-async function fetchCursorModelsCli(installPath: string): Promise<ProviderModel[]> {
-  try {
-    const { stdout } = await exec(`"${installPath}" models`, { timeout: 15_000, maxBuffer: 1024 * 1024 });
-    return parseCursorAgentModelsOutput(stdout);
-  } catch {
-    return [];
-  }
-}
-
 /** Prefix llama-swap model ids so they don't collide with provider-native models. */
 export function prefixLlamaSwapModels(models: ProviderModel[]): ProviderModel[] {
   return models.map((m) => ({
@@ -82,112 +72,155 @@ export function mergeModels(...lists: ProviderModel[][]): ProviderModel[] {
 }
 
 async function buildProviderEntry(
-  provider: ProviderDef,
+  resolved: ResolvedProviderDef,
   agentRow: AgentRow | undefined,
   llamaModels: ProviderModel[],
   cwd: string,
-): Promise<ProviderSnapshotEntry | null> {
+  ttlMs: number,
-  const isNative = provider.name === 'boocode';
+  force: boolean,
-  const installed = isNative || !!agentRow;
+): Promise<ProviderSnapshotEntry> {
-  if (!installed) return null;
+  const name = resolved.id;
+  const isNative = resolved.transport === 'native';
+  const fallbackModes = getManifestModes(name);
+  const defaultModeId = getManifestDefaultModeId(name);
+  const manifestCommands = getManifestCommands(name);
+  // Manifest + persisted live ACP commands (captured on a prior cold probe), so
+  // the agent's discovered commands show even when the tier-2 probe is skipped.
+  const dbCommands = mergeCommands(manifestCommands, agentRow?.commands ?? []);
+  const label = agentRow?.label ?? resolved.configLabel ?? resolved.label;
+  const descr = resolved.configDescription ? { description: resolved.configDescription } : {};
 
-  let transport = provider.transport;
+  // v2.3: config `models` REPLACES the discovered/static list; `additionalModels`
-  if (agentRow && provider.transport === 'acp' && !agentRow.supports_acp) {
+  // MERGES on top. Applied to every ready/installed model list below.
+  const withConfigModels = (m: ProviderModel[]): ProviderModel[] => {
+    let out = resolved.configModels && resolved.configModels.length > 0 ? resolved.configModels : m;
+    if (resolved.configAdditionalModels && resolved.configAdditionalModels.length > 0) {
+      out = mergeModels(out, resolved.configAdditionalModels);
+    }
+    return out;
+  };
+
+  // ACP built-ins fall back to PTY transport when the installed binary lacks ACP.
+  let transport = resolved.transport;
+  if (agentRow && resolved.transport === 'acp' && !agentRow.supports_acp) {
     transport = 'pty';
   }
 
-  const fallbackModes = getManifestModes(provider.name);
+  // 1. Disabled → unavailable, no probe.
-  const defaultModeId = getManifestDefaultModeId(provider.name);
+  if (!resolved.enabled) {
-
-  if (isNative) {
     return {
-      name: provider.name,
+      name, label, ...descr, transport, status: 'unavailable',
-      label: provider.label,
+      enabled: false, installed: false, models: [], modes: fallbackModes,
-      transport,
+      defaultModeId, commands: manifestCommands,
-      status: 'ready',
-      installed: true,
-      models: llamaModels,
-      modes: [],
-      defaultModeId: null,
-      commands: getManifestCommands(provider.name),
     };
   }
 
+  // 2. Native boocode → always ready (llama-swap models).
+  if (isNative) {
+    return {
+      name, label: resolved.label, transport, status: 'ready',
+      enabled: true, installed: true, models: withConfigModels(llamaModels), modes: [],
+      defaultModeId: null, commands: manifestCommands,
+    };
+  }
+
+  // 3. Tier-1 fast availability: installed iff a probed install_path exists or
+  // the launch binary is on PATH. No spawn beyond a `which` for custom entries.
+  const fast =
+    agentRow?.install_path != null ||
+    (resolved.launchCommand ? await isCommandAvailable(resolved.launchCommand[0]) : false);
+
+  if (!fast) {
+    return {
+      name, label, ...descr, transport, status: 'unavailable',
+      enabled: true, installed: false, models: [], modes: fallbackModes,
+      defaultModeId, commands: manifestCommands,
+    };
+  }
+
+  // Baseline model precedence (used by claude + non-probe fallbacks).
   let models: ProviderModel[] = [];
-  if (provider.modelSource === 'llama-swap' && provider.mergeLlamaSwap) {
+  if (resolved.modelSource === 'llama-swap' && resolved.mergeLlamaSwap) {
     models = llamaModels;
   } else if (agentRow?.models?.length) {
     models = agentRow.models;
-  } else if (provider.staticModels) {
+  } else if (resolved.staticModels) {
-    models = provider.staticModels.map((m) => ({ id: m.id, label: m.label }));
+    models = resolved.staticModels.map((m) => ({ id: m.id, label: m.label }));
   }
 
-  if (provider.name === 'claude') {
+  // claude: static models + thinking options, no ACP probe (unchanged from v2.2).
-    models = attachClaudeThinking(models);
+  if (name === 'claude') {
+    // claude is PTY (no ACP discovery) — read its enabled commands + plugin
+    // skills from disk live (the snapshot cache rate-limits the fs reads).
     return {
-      name: provider.name,
+      name, label, transport, status: 'ready', enabled: true, installed: true,
-      label: agentRow?.label ?? provider.label,
+      models: attachClaudeThinking(withConfigModels(models)), modes: fallbackModes, defaultModeId,
-      transport,
+      commands: mergeCommands(manifestCommands, discoverClaudeCommands()),
-      status: 'ready',
-      installed: true,
-      models,
-      modes: fallbackModes,
-      defaultModeId,
-      commands: getManifestCommands(provider.name),
     };
   }
 
-  if (transport === 'acp' && agentRow?.install_path && agentRow.supports_acp) {
+  const canProbeAcp =
-    const probe = await probeAcpProvider(provider.name, agentRow.install_path, cwd);
+    transport === 'acp' &&
-    if (probe.models.length > 0) {
+    ((agentRow?.install_path != null && agentRow.supports_acp) ||
-      models = probe.models;
+      (resolved.isCustomAcp && resolved.launchCommand != null));
-    } else if (provider.name === 'cursor' && agentRow.install_path) {
+
-      models = await fetchCursorModelsCli(agentRow.install_path);
+  if (canProbeAcp) {
-    } else if (provider.modelSource === 'llama-swap') {
+    // Tier-2 gate (§4.3): cold ACP probe only on force, staleness, or empty DB
-      models = llamaModels;
+    // models. Otherwise serve DB models + manifest modes/commands — no spawn.
+    const lastProbedMs =
+      agentRow?.last_probed_at != null ? new Date(agentRow.last_probed_at).getTime() : NaN;
+    const stale = Number.isNaN(lastProbedMs) || Date.now() - lastProbedMs > ttlMs;
+    const dbEmpty = !(agentRow?.models && agentRow.models.length > 0);
+    const runTier2 = force || stale || dbEmpty;
+
+    if (!runTier2) {
+      let skipModels = agentRow?.models ?? [];
+      if (resolved.mergeLlamaSwap && resolved.modelSource !== 'llama-swap') {
+        skipModels = mergeModels(skipModels, prefixLlamaSwapModels(llamaModels));
+      } else if (resolved.modelSource === 'llama-swap' && skipModels.length === 0) {
+        skipModels = llamaModels;
+      }
+      return {
+        name, label, transport, status: 'ready', enabled: true, installed: true,
+        models: withConfigModels(skipModels), modes: fallbackModes, defaultModeId, commands: dbCommands,
+      };
     }
 
-    if (provider.name === 'qwen') {
+    const probeTarget =
-      const settingsModels = await readQwenSettingsModels();
+      resolved.isCustomAcp && resolved.launchCommand
-      models = mergeModels(models, settingsModels);
+        ? resolved.launchCommand[0]
-    }
+        : agentRow!.install_path!;
+    const probe = await probeAcpProvider(name, probeTarget, cwd);
 
-    if (provider.mergeLlamaSwap && provider.modelSource !== 'llama-swap') {
+    let probeModels = probe.models.length > 0 ? probe.models : models;
-      const nativeModels = probe.models.length > 0 ? probe.models : models;
+    if (name === 'qwen') {
-      models = mergeModels(nativeModels, prefixLlamaSwapModels(llamaModels));
+      probeModels = mergeModels(probeModels, await readQwenSettingsModels());
+    }
+    if (resolved.mergeLlamaSwap && resolved.modelSource !== 'llama-swap') {
+      const nativeModels = probe.models.length > 0 ? probe.models : probeModels;
+      probeModels = mergeModels(nativeModels, prefixLlamaSwapModels(llamaModels));
     }
 
     return {
-      name: provider.name,
+      name, label, transport,
-      label: agentRow.label ?? provider.label,
-      transport,
       status: probe.ok ? 'ready' : 'error',
-      installed: true,
+      enabled: true, installed: true,
-      models,
+      models: withConfigModels(probeModels),
       modes: probe.modes.length > 0 ? probe.modes : fallbackModes,
       defaultModeId: probe.defaultModeId ?? defaultModeId,
-      commands: mergeCommands(getManifestCommands(provider.name), probe.commands),
+      commands: mergeCommands(manifestCommands, probe.commands),
-      error: probe.error,
+      ...(probe.error ? { error: probe.error } : {}),
+      fetchedAt: new Date().toISOString(),
     };
   }
 
-  // PTY-only providers (qwen fallback when ACP unavailable)
+  // PTY-only fallback (e.g. qwen without ACP) — installed + ready.
-  if (provider.name === 'qwen') {
+  if (name === 'qwen' && models.length === 0) {
-    if (models.length === 0) {
     models = await readQwenSettingsModels();
   }
-  }
-
   return {
-    name: provider.name,
+    name, label, transport, status: 'ready', enabled: true, installed: true,
-    label: agentRow?.label ?? provider.label,
+    models: withConfigModels(models), modes: fallbackModes, defaultModeId, commands: dbCommands,
-    transport,
-    status: 'ready',
-    installed: true,
-    models,
-    modes: fallbackModes,
-    defaultModeId,
-    commands: getManifestCommands(provider.name),
   };
 }
 
@@ -216,16 +249,16 @@ export async function getProviderSnapshot(
   const build = async (): Promise<ProviderSnapshotEntry[]> => {
     const llamaModels = await fetchLlamaSwapModels(config);
     const agents = await sql<AgentRow[]>`
-      SELECT name, install_path, supports_acp, models, label, transport FROM available_agents
+      SELECT name, install_path, supports_acp, models, commands, label, transport, last_probed_at FROM available_agents
     `;
     const agentMap = new Map(agents.map((a) => [a.name, a]));
+    const ttlMs = config.PROVIDER_PROBE_TTL_MS;
 
-    const built = await Promise.all(
+    const entries = await Promise.all(
-      PROVIDERS.map((provider) =>
+      [...getResolvedRegistry().values()].map((resolved) =>
-        buildProviderEntry(provider, agentMap.get(provider.name), llamaModels, resolvedCwd),
+        buildProviderEntry(resolved, agentMap.get(resolved.id), llamaModels, resolvedCwd, ttlMs, force),
       ),
     );
-    const entries = built.filter((entry): entry is ProviderSnapshotEntry => entry !== null);
 
     snapshotCache.set(cacheKey, { at: Date.now(), entries });
     return entries;
@@ -235,6 +268,13 @@ export async function getProviderSnapshot(
     snapshotInflight.delete(cacheKey);
   });
   snapshotInflight.set(cacheKey, promise);
+
+  // Await the build (force or cache-miss) and return terminal entries. The sync
+  // `loading` return (design §4.4) is DEFERRED until Phase 5 ships the client
+  // poll that resolves it: without that poll, a single fetch lands on
+  // installed:false `loading` entries, which AgentComposerBar filters out
+  // (`e.installed && ...`) → empty picker. Builds stay fast via the tier-2 skip
+  // once available_agents.models is warm.
   return promise;
 }
 
@@ -243,6 +283,16 @@ export function clearProviderSnapshotCache(): void {
   snapshotInflight.clear();
 }
 
+/**
+ * Read-only peek into the warm snapshot cache for one provider (no build, no
+ * probe). Used by the diagnostic route to report the last computed probe error
+ * without spawning anything. Returns undefined on a cold cache / unknown name.
+ */
+export function peekSnapshotEntry(name: string, cwd?: string): ProviderSnapshotEntry | undefined {
+  const resolvedCwd = cwd?.trim() || homedir();
+  return snapshotCache.get(resolvedCwd)?.entries.find((e) => e.name === name);
+}
+
 /** Persist probed model lists back to available_agents for fast legacy reads. */
 export async function persistProbedModels(
   sql: Sql,
@@ -251,16 +301,34 @@ export async function persistProbedModels(
 ): Promise<void> {
   let count = 0;
   for (const entry of entries) {
-    if (entry.name === 'boocode' || entry.models.length === 0) continue;
+    if (entry.name === 'boocode') continue;
+    let persisted = false;
+    if (entry.models.length > 0) {
       const flatModels = entry.models.map(({ id, label }) => ({ id, label }));
       await sql`
         UPDATE available_agents
         SET models = ${sql.json(flatModels as never)}, last_probed_at = clock_timestamp()
         WHERE name = ${entry.name}
       `;
-    count++;
+      persisted = true;
+    }
+    // Persist captured ACP commands so they survive the tier-2 probe skip and
+    // show without a dispatch. Only when non-empty — never clobber a prior set.
+    if (entry.commands.length > 0) {
+      const flatCommands = entry.commands.map((c) => ({
+        name: c.name,
+        ...(c.description ? { description: c.description } : {}),
+      }));
+      await sql`
+        UPDATE available_agents
+        SET commands = ${sql.json(flatCommands as never)}, last_probed_at = clock_timestamp()
+        WHERE name = ${entry.name}
+      `;
+      persisted = true;
+    }
+    if (persisted) count++;
   }
   if (count > 0) {
-    log.info({ count }, 'provider-snapshot: persisted models to available_agents');
+    log.info({ count }, 'provider-snapshot: persisted models/commands to available_agents');
   }
 }

apps/coder/src/services/provider-types.ts

@@ -23,24 +23,34 @@ export interface ProviderModel {
   defaultThinkingOptionId?: string;
 }
 
-export type ProviderSnapshotStatus = 'ready' | 'error';
+// v2.3 phase 2: 'loading' (cache-miss, probe in flight) + 'unavailable'
+// (disabled or not installed) restored alongside the terminal 'ready' | 'error'.
+export type ProviderSnapshotStatus = 'loading' | 'ready' | 'unavailable' | 'error';
 
 export interface AgentCommand {
   name: string;
   description?: string;
+  // v2.5.11: 'skill' (plugin skill) vs 'command' (native/CLI slash command).
+  // Drives the icon split in the coder slash menu. Undefined → command.
+  kind?: 'command' | 'skill';
 }
 
+// KEEP IN SYNC with apps/web/src/api/types.ts ProviderSnapshotEntry — parity is
+// enforced by __tests__/provider-types-parity.test.ts (fails on any field drift).
 export interface ProviderSnapshotEntry {
   name: string;
   label: string;
+  description?: string;
   transport: string;
   status: ProviderSnapshotStatus;
+  enabled: boolean;
   installed: boolean;
   models: ProviderModel[];
   modes: ProviderMode[];
   defaultModeId: string | null;
   commands: AgentCommand[];
   error?: string;
+  fetchedAt?: string;
 }
 
 export interface AgentSessionConfig {

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

@@ -1,13 +1,29 @@
 /**
  * PTY dispatch — runs external agents directly on the host.
+ *
+ * claude + qwen run with `--output-format stream-json` and emit Claude-Code's
+ * stream-json NDJSON on stdout. When an `onEvent` callback is supplied we
+ * line-buffer that stdout (split on `\n`, hold the partial tail) and feed complete
+ * lines to `makeStreamJsonParser` so deltas surface live as AgentEvents. The raw
+ * stdout is still accumulated + returned for back-compat (and the dispatcher's
+ * fallback when nothing parsed). See `stream-json-parser.ts`.
  */
 import type { FastifyBaseLogger } from 'fastify';
 import { spawn } from 'node:child_process';
+import type { AgentEvent } from './agent-backend.js';
+import { makeStreamJsonParser, type StreamJsonUsage } from './stream-json-parser.js';
 
 export interface DispatchResult {
   exitCode: number;
   stdout: string;
   stderr: string;
+  /** True iff at least one NDJSON AgentEvent was parsed from stdout (v#7). When
+   *  false the dispatcher falls back to slicing stdout as the assistant content. */
+  streamed: boolean;
+  /** Final usage parsed from the stream-json `result` / `message_delta`, if any. */
+  usage?: StreamJsonUsage;
+  /** Provider session id from the stream-json `system` init line, if any. */
+  agentSessionId?: string | null;
 }
 
 export interface PtyDispatchOpts {
@@ -20,6 +36,10 @@ export interface PtyDispatchOpts {
   installPath?: string;
   signal?: AbortSignal;
   log: FastifyBaseLogger;
+  /** Optional live event sink. When set, stdout is line-buffered + NDJSON-parsed
+   *  and each AgentEvent is forwarded here as it arrives. Absent → opaque (old)
+   *  behavior: stdout is accumulated and returned, no parsing. */
+  onEvent?: (e: AgentEvent) => void;
 }
 
 interface PtySpawnSpec {
@@ -40,7 +60,9 @@ function buildPtySpawnSpec(
 
   switch (agent) {
     case 'claude': {
-      const args = ['-p'];
+      // stream-json on -p requires --verbose (Claude Code rejects stream-json
+      // print mode without it). qwen needs no such flag.
+      const args = ['-p', '--output-format', 'stream-json', '--verbose'];
       if (model) args.push('--model', model);
       if (modeId) args.push('--permission-mode', modeId);
       if (thinkingOptionId) args.push('--effort', thinkingOptionId);
@@ -73,7 +95,7 @@ function buildPtySpawnSpec(
 }
 
 export async function dispatchViaPty(opts: PtyDispatchOpts): Promise<DispatchResult> {
-  const { agent, task, worktreePath, model, modeId, thinkingOptionId, installPath, signal, log } = opts;
+  const { agent, task, worktreePath, model, modeId, thinkingOptionId, installPath, signal, log, onEvent } = opts;
 
   const cmd = buildPtySpawnSpec(agent, task, model, modeId, thinkingOptionId, installPath);
   if (!cmd) {
@@ -81,6 +103,7 @@ export async function dispatchViaPty(opts: PtyDispatchOpts): Promise<DispatchRes
       exitCode: 1,
       stdout: '',
       stderr: `Agent '${agent}' is not yet supported for PTY dispatch.`,
+      streamed: false,
     };
   }
 
@@ -102,7 +125,32 @@ export async function dispatchViaPty(opts: PtyDispatchOpts): Promise<DispatchRes
     let stderr = '';
     let killed = false;
 
-    child.stdout!.on('data', (chunk: Buffer) => { stdout += chunk.toString(); });
+    // Live NDJSON parsing (only when a sink is supplied). Line-buffer: split on
+    // '\n', dispatch complete lines, hold the partial tail until the next chunk.
+    const parser = onEvent ? makeStreamJsonParser() : null;
+    let lineBuf = '';
+    let streamed = false;
+    const feedLine = (line: string): void => {
+      if (!parser || !onEvent) return;
+      for (const e of parser.push(line)) {
+        streamed = true;
+        onEvent(e);
+      }
+    };
+
+    child.stdout!.on('data', (chunk: Buffer) => {
+      const text = chunk.toString();
+      stdout += text;
+      if (!parser) return;
+      lineBuf += text;
+      let nl = lineBuf.indexOf('\n');
+      while (nl !== -1) {
+        const line = lineBuf.slice(0, nl);
+        lineBuf = lineBuf.slice(nl + 1);
+        feedLine(line);
+        nl = lineBuf.indexOf('\n');
+      }
+    });
     child.stderr!.on('data', (chunk: Buffer) => { stderr += chunk.toString(); });
 
     const cleanup = () => {
@@ -116,7 +164,7 @@ export async function dispatchViaPty(opts: PtyDispatchOpts): Promise<DispatchRes
     if (signal) {
       if (signal.aborted) {
         cleanup();
-        resolve({ exitCode: 130, stdout: '', stderr: 'Aborted before start' });
+        resolve({ exitCode: 130, stdout: '', stderr: 'Aborted before start', streamed: false });
         return;
       }
       signal.addEventListener('abort', cleanup, { once: true });
@@ -124,8 +172,18 @@ export async function dispatchViaPty(opts: PtyDispatchOpts): Promise<DispatchRes
 
     child.on('close', (code) => {
       if (signal) signal.removeEventListener('abort', cleanup);
-      log.info({ agent, exitCode: code }, 'pty-dispatch: completed');
+      // Flush any final line with no trailing newline.
-      resolve({ exitCode: code ?? 1, stdout, stderr });
+      if (lineBuf.trim()) feedLine(lineBuf);
+      lineBuf = '';
+      log.info({ agent, exitCode: code, streamed }, 'pty-dispatch: completed');
+      resolve({
+        exitCode: code ?? 1,
+        stdout,
+        stderr,
+        streamed,
+        usage: parser?.usage(),
+        agentSessionId: parser?.sessionId() ?? null,
+      });
     });
 
     child.on('error', (err) => {

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

@@ -0,0 +1,296 @@
+/**
+ * Claude-Code-compatible stream-json NDJSON parser (feature #7,
+ * openspec `sampling-streamjson-tokens`).
+ *
+ * qwen (`--output-format stream-json`) and claude (`--output-format stream-json`)
+ * both emit Claude-Code's stream-json NDJSON on stdout: one JSON object per line.
+ * This module turns that stream into the same transport-agnostic `AgentEvent`s the
+ * ACP / opencode-server backends emit, so the PTY dispatch path can publish live
+ * broker frames + persist structured parts instead of slicing stdout opaque.
+ *
+ * Two surfaces:
+ *  - `parseStreamJsonLine(line, state)` — PURE per-line mapping (unit-testable).
+ *    `state` is the caller-owned accumulator (open tool blocks + usage/session_id).
+ *  - `makeStreamJsonParser()` — a thin stateful wrapper holding the state, with a
+ *    `push(line)` that returns the events for that line and getters for the final
+ *    `usage` / `sessionId`.
+ *
+ * Defensive by contract: a non-JSON / partial / garbage line yields `[]` and never
+ * throws. Tool args (`input_json_delta`) arrive fragmented across many lines; we
+ * accumulate the partial JSON string per content-block index and only surface the
+ * parsed `rawInput` once the block stops (or, as a fallback, off the terminal
+ * `assistant` message which carries the fully-assembled `tool_use` blocks).
+ *
+ * Schema (keyed on top-level `type`):
+ *  - `system`     — init: { session_id, tools, ... }
+ *  - `assistant`  — { message: { content: [ {type:'text'|'thinking'|'tool_use', ...} ], usage? } }
+ *  - `user`       — tool results (ignored — diffing the worktree captures effects)
+ *  - `result`     — final: { usage: { input_tokens, output_tokens }, session_id? }
+ *  - `stream_event` — { event: { type, index?, content_block?, delta?, usage? } }
+ *      event.type:
+ *        content_block_start  — { index, content_block: {type, id?, name?} }
+ *        content_block_delta  — { index, delta: {type, text?|thinking?|partial_json?} }
+ *        content_block_stop   — { index }
+ *        message_delta        — { usage: { output_tokens } }
+ *        message_start        — { message: { usage } }
+ */
+import type { AgentEvent } from './agent-backend.js';
+import type { AcpToolSnapshot } from './acp-tool-snapshot.js';
+
+/** Convenience alias for the per-line return value. */
+export type AgentEventList = AgentEvent[];
+
+export interface StreamJsonUsage {
+  inputTokens?: number;
+  outputTokens?: number;
+}
+
+/** Per-open-content-block accumulation for tool args assembled across deltas. */
+interface OpenToolBlock {
+  toolCallId: string;
+  name: string;
+  /** Concatenated `input_json_delta.partial_json` fragments. */
+  partialJson: string;
+}
+
+export interface StreamJsonState {
+  /** content-block index → open tool block (only `tool_use` blocks are tracked). */
+  toolBlocks: Map<number, OpenToolBlock>;
+  sessionId: string | null;
+  usage: StreamJsonUsage;
+}
+
+export function makeStreamJsonState(): StreamJsonState {
+  return { toolBlocks: new Map(), sessionId: null, usage: {} };
+}
+
+function asRecord(value: unknown): Record<string, unknown> | null {
+  if (value && typeof value === 'object' && !Array.isArray(value)) {
+    return value as Record<string, unknown>;
+  }
+  return null;
+}
+
+function asString(value: unknown): string | undefined {
+  return typeof value === 'string' ? value : undefined;
+}
+
+function asNumber(value: unknown): number | undefined {
+  return typeof value === 'number' && Number.isFinite(value) ? value : undefined;
+}
+
+/** Pull token counts out of an Anthropic-shape `usage` object, mutating state. */
+function captureUsage(usage: Record<string, unknown> | null, state: StreamJsonState): void {
+  if (!usage) return;
+  const input = asNumber(usage.input_tokens);
+  const output = asNumber(usage.output_tokens);
+  if (input !== undefined) state.usage.inputTokens = input;
+  // output_tokens is reported incrementally on message_delta; keep the latest.
+  if (output !== undefined) state.usage.outputTokens = output;
+}
+
+/** Parse the accumulated tool-arg JSON; tolerate an unparseable/partial body. */
+function parseToolInput(partialJson: string): unknown {
+  const trimmed = partialJson.trim();
+  if (!trimmed) return {};
+  try {
+    return JSON.parse(trimmed);
+  } catch {
+    return { _raw: partialJson };
+  }
+}
+
+function toolSnapshot(block: OpenToolBlock, rawInput: unknown, status: AcpToolSnapshot['status']): AcpToolSnapshot {
+  return {
+    toolCallId: block.toolCallId,
+    title: block.name,
+    kind: null,
+    status,
+    rawInput,
+  };
+}
+
+/**
+ * Map one stream-event sub-object (the `event` field of a `stream_event` line) to
+ * AgentEvents, mutating `state` for open tool blocks + usage.
+ */
+function handleStreamEvent(event: Record<string, unknown>, state: StreamJsonState): AgentEvent[] {
+  const eventType = asString(event.type);
+  if (!eventType) return [];
+
+  switch (eventType) {
+    case 'content_block_start': {
+      const index = asNumber(event.index);
+      const block = asRecord(event.content_block);
+      if (index === undefined || !block) return [];
+      if (asString(block.type) !== 'tool_use') return [];
+      const toolCallId = asString(block.id) ?? `tool_${index}`;
+      const name = asString(block.name) ?? 'tool';
+      const open: OpenToolBlock = { toolCallId, name, partialJson: '' };
+      state.toolBlocks.set(index, open);
+      // Surface the tool start immediately (running, no args yet) so the UI shows
+      // the call before the args finish streaming.
+      return [{ type: 'tool_call', toolCall: toolSnapshot(open, {}, 'in_progress') }];
+    }
+
+    case 'content_block_delta': {
+      const index = asNumber(event.index);
+      const delta = asRecord(event.delta);
+      if (delta === null) return [];
+      const deltaType = asString(delta.type);
+      if (deltaType === 'text_delta') {
+        const text = asString(delta.text);
+        return text ? [{ type: 'text', text }] : [];
+      }
+      if (deltaType === 'thinking_delta') {
+        const text = asString(delta.thinking);
+        return text ? [{ type: 'reasoning', text }] : [];
+      }
+      if (deltaType === 'input_json_delta') {
+        // Accumulate tool args; no event until the block stops.
+        const fragment = asString(delta.partial_json);
+        if (index !== undefined && fragment) {
+          const open = state.toolBlocks.get(index);
+          if (open) open.partialJson += fragment;
+        }
+        return [];
+      }
+      return [];
+    }
+
+    case 'content_block_stop': {
+      const index = asNumber(event.index);
+      if (index === undefined) return [];
+      const open = state.toolBlocks.get(index);
+      if (!open) return [];
+      state.toolBlocks.delete(index);
+      const rawInput = parseToolInput(open.partialJson);
+      return [{ type: 'tool_update', toolCall: toolSnapshot(open, rawInput, 'completed') }];
+    }
+
+    case 'message_start': {
+      const message = asRecord(event.message);
+      captureUsage(asRecord(message?.usage), state);
+      return [];
+    }
+
+    case 'message_delta': {
+      captureUsage(asRecord(event.usage), state);
+      return [];
+    }
+
+    default:
+      return [];
+  }
+}
+
+/**
+ * Map the terminal `assistant` message (post-hoc full message) to AgentEvents. Used
+ * as a fallback for transports that emit only the assembled `assistant` line and no
+ * incremental `stream_event`s. When stream_events already streamed a block, the
+ * caller dedups by toolCallId, so re-emitting the assembled tool_use is harmless.
+ */
+function handleAssistantMessage(message: Record<string, unknown>, state: StreamJsonState): AgentEvent[] {
+  captureUsage(asRecord(message.usage), state);
+  const content = message.content;
+  if (!Array.isArray(content)) return [];
+  const out: AgentEvent[] = [];
+  let toolIdx = 0;
+  for (const rawBlock of content) {
+    const block = asRecord(rawBlock);
+    if (!block) continue;
+    const blockType = asString(block.type);
+    if (blockType === 'text') {
+      const text = asString(block.text);
+      if (text) out.push({ type: 'text', text });
+    } else if (blockType === 'thinking') {
+      const text = asString(block.thinking);
+      if (text) out.push({ type: 'reasoning', text });
+    } else if (blockType === 'tool_use') {
+      const toolCallId = asString(block.id) ?? `tool_${toolIdx}`;
+      const name = asString(block.name) ?? 'tool';
+      const rawInput = 'input' in block ? block.input : {};
+      out.push({
+        type: 'tool_update',
+        toolCall: { toolCallId, title: name, kind: null, status: 'completed', rawInput },
+      });
+    }
+    toolIdx++;
+  }
+  return out;
+}
+
+/**
+ * Pure per-line mapping. `line` is a single complete NDJSON line (no trailing
+ * newline required; surrounding whitespace tolerated). Returns the AgentEvents the
+ * line produces and mutates `state` (open tool blocks, usage, session_id). A blank,
+ * non-JSON, or unrecognized line yields `[]` and never throws.
+ */
+export function parseStreamJsonLine(line: string, state: StreamJsonState): AgentEvent[] {
+  const trimmed = line.trim();
+  if (!trimmed) return [];
+
+  let obj: Record<string, unknown> | null;
+  try {
+    const parsed: unknown = JSON.parse(trimmed);
+    obj = asRecord(parsed);
+  } catch {
+    return [];
+  }
+  if (!obj) return [];
+
+  const type = asString(obj.type);
+  switch (type) {
+    case 'system': {
+      const sid = asString(obj.session_id);
+      if (sid) state.sessionId = sid;
+      return [];
+    }
+
+    case 'stream_event': {
+      const event = asRecord(obj.event);
+      return event ? handleStreamEvent(event, state) : [];
+    }
+
+    case 'assistant': {
+      const sid = asString(obj.session_id);
+      if (sid) state.sessionId = sid;
+      const message = asRecord(obj.message);
+      return message ? handleAssistantMessage(message, state) : [];
+    }
+
+    case 'result': {
+      const sid = asString(obj.session_id);
+      if (sid) state.sessionId = sid;
+      captureUsage(asRecord(obj.usage), state);
+      return [];
+    }
+
+    default:
+      // `user` (tool results) and any unknown line type — ignore.
+      return [];
+  }
+}
+
+export interface StreamJsonParser {
+  /** Feed one complete NDJSON line; returns its AgentEvents (never throws). */
+  push(line: string): AgentEvent[];
+  /** Final usage (input/output tokens) accumulated so far. */
+  usage(): StreamJsonUsage;
+  /** Provider session id from the init `system` line / `result`, if seen. */
+  sessionId(): string | null;
+}
+
+/**
+ * Stateful wrapper around `parseStreamJsonLine`. Holds per-tool-block accumulation
+ * + usage/session_id across the turn. Line-buffering (splitting stdout on `\n` and
+ * holding the partial tail) is the caller's job — see `pty-dispatch.ts`.
+ */
+export function makeStreamJsonParser(): StreamJsonParser {
+  const state = makeStreamJsonState();
+  return {
+    push: (line: string) => parseStreamJsonLine(line, state),
+    usage: () => ({ ...state.usage }),
+    sessionId: () => state.sessionId,
+  };
+}

apps/coder/src/services/worktrees.ts

@@ -6,9 +6,10 @@
  * After the agent completes, we diff the worktree against HEAD and
  * queue the diff into pending_changes.
  */
+import type { Sql } from '../db.js';
 import { hostExec } from './host-exec.js';
 
-const WORKTREE_BASE = '/tmp/booworktrees';
+export const WORKTREE_BASE = '/tmp/booworktrees';
 
 /**
  * Create a git worktree for a task on the host.
@@ -45,7 +46,7 @@ export async function createWorktree(
 export async function diffWorktree(
   worktreePath: string,
   projectPath: string,
-  opts?: { signal?: AbortSignal },
+  opts?: { signal?: AbortSignal; baseRef?: string },
 ): Promise<string> {
   // First, commit any uncommitted changes in the worktree so we can diff branches
   // Stage all changes
@@ -74,9 +75,13 @@ export async function diffWorktree(
     { signal: opts?.signal, timeoutMs: 15_000 },
   );
 
-  // Diff the worktree branch against the parent commit (HEAD of main tree)
+  // Diff the worktree branch against the baseline. Per-task callers default to the
+  // main tree's current HEAD; the session-worktree (opencode) path passes the
+  // captured base_commit so the accumulated diff is stable across turns even if
+  // project HEAD advances.
+  const baseRef = opts?.baseRef ?? 'HEAD';
   const diffResult = await hostExec(
-    `git -C ${shellEscape(projectPath)} diff HEAD...$(git -C ${shellEscape(worktreePath)} rev-parse HEAD)`,
+    `git -C ${shellEscape(projectPath)} diff ${shellEscape(baseRef)}...$(git -C ${shellEscape(worktreePath)} rev-parse HEAD)`,
     { signal: opts?.signal, timeoutMs: 60_000 },
   );
 
@@ -111,6 +116,427 @@ export async function cleanupWorktree(
   ).catch(() => {});
 }
 
+// ─── v2.6: session-keyed persistent worktree ────────────────────────────────
+
+export interface SessionWorktree {
+  /** P1.5-b: the `worktrees.id` — stored on agent_sessions informationally. */
+  worktreeId: string;
+  worktreePath: string;
+  baseCommit: string | null;
+}
+
+/**
+ * v2.6 / P1.5-b: create-or-reuse ONE worktree per BooCode session (shared across
+ * all tabs/agents in the session), recorded in `worktrees` (was the superseded
+ * `session_worktrees`). Persists — NOT torn down per turn (cleanup is Phase 3) —
+ * and now survives session delete (`worktrees.session_id` is ON DELETE SET NULL).
+ * Captures the project's current HEAD as `base_commit` for a stable diff baseline.
+ *
+ * Distinct path namespace (`session-<id>` branch, `/sess-<id>` dir) so it never
+ * collides with the per-task worktrees that arena/new_task/MCP still use.
+ */
+export async function ensureSessionWorktree(
+  sql: Sql,
+  projectPath: string,
+  sessionId: string,
+  opts?: { signal?: AbortSignal },
+): Promise<SessionWorktree> {
+  const [existing] = await sql<{ id: string; path: string; base_commit: string | null }[]>`
+    SELECT id, path, base_commit FROM worktrees
+    WHERE session_id = ${sessionId} AND status = 'active'
+    LIMIT 1
+  `;
+  if (existing) {
+    return { worktreeId: existing.id, worktreePath: existing.path, baseCommit: existing.base_commit };
+  }
+
+  const worktreePath = `${WORKTREE_BASE}/sess-${sessionId}`;
+  const branchName = `session-${sessionId}`;
+
+  await hostExec(`mkdir -p ${WORKTREE_BASE}`, { signal: opts?.signal });
+
+  // Capture the baseline commit BEFORE branching, so the diff is stable even if
+  // project HEAD later advances.
+  const headResult = await hostExec(
+    `git -C ${shellEscape(projectPath)} rev-parse HEAD`,
+    { signal: opts?.signal, timeoutMs: 10_000 },
+  );
+  const baseCommit = headResult.exitCode === 0 ? headResult.stdout.trim() || null : null;
+
+  const result = await hostExec(
+    `git -C ${shellEscape(projectPath)} worktree add ${shellEscape(worktreePath)} -b ${shellEscape(branchName)} HEAD`,
+    { signal: opts?.signal, timeoutMs: 30_000 },
+  );
+  if (result.exitCode !== 0) {
+    throw new Error(`Failed to create session worktree: ${result.stderr.trim() || result.stdout.trim()}`);
+  }
+
+  // Insert-or-get: WHERE NOT EXISTS keeps the first writer's row if two turns race
+  // the create (the partial unique on active path also backstops it).
+  const [inserted] = await sql<{ id: string; path: string; base_commit: string | null }[]>`
+    INSERT INTO worktrees (session_id, path, branch, base_commit, status)
+    SELECT ${sessionId}, ${worktreePath}, ${branchName}, ${baseCommit}, 'active'
+    WHERE NOT EXISTS (
+      SELECT 1 FROM worktrees WHERE session_id = ${sessionId} AND status = 'active'
+    )
+    RETURNING id, path, base_commit
+  `;
+  if (inserted) {
+    return { worktreeId: inserted.id, worktreePath: inserted.path, baseCommit: inserted.base_commit };
+  }
+  // Lost the race — another turn inserted first; read its row.
+  const [row] = await sql<{ id: string; path: string; base_commit: string | null }[]>`
+    SELECT id, path, base_commit FROM worktrees
+    WHERE session_id = ${sessionId} AND status = 'active'
+    LIMIT 1
+  `;
+  return {
+    worktreeId: row!.id,
+    worktreePath: row?.path ?? worktreePath,
+    baseCommit: row?.base_commit ?? baseCommit,
+  };
+}
+
+/**
+ * v2.6 Phase 3 (3.3 / 3.4): physically remove a session's persistent worktree —
+ * the git worktree dir + its branch — and archive its `worktrees` row. Used by the
+ * chat/session-close hook (when the last chat in a session closes) and the orphan
+ * reaper. Best-effort on the git side (a dir already gone is not an error); the DB
+ * row is flipped to 'archived' (soft-delete, Paseo's worktree-archive pattern) so
+ * history/attribution survives and a re-run is idempotent.
+ *
+ * SAFETY: callers MUST run `checkWorktreeWorkAtRisk` first and skip at-risk
+ * worktrees — this function force-removes (`--force`), so it never silently drops
+ * uncommitted/unmerged work unless the caller already cleared/accepted the risk.
+ */
+export async function removeSessionWorktree(
+  sql: Sql,
+  projectPath: string,
+  worktree: { id: string; path: string; branch?: string | null },
+  opts?: { signal?: AbortSignal },
+): Promise<void> {
+  await hostExec(
+    `git -C ${shellEscape(projectPath)} worktree remove ${shellEscape(worktree.path)} --force`,
+    { signal: opts?.signal, timeoutMs: 15_000 },
+  ).catch(() => {});
+  const branch = worktree.branch ?? null;
+  if (branch) {
+    await hostExec(
+      `git -C ${shellEscape(projectPath)} branch -D ${shellEscape(branch)}`,
+      { signal: opts?.signal, timeoutMs: 10_000 },
+    ).catch(() => {});
+  }
+  // Prune any stale worktree administrative entries left behind by a partial remove.
+  await hostExec(
+    `git -C ${shellEscape(projectPath)} worktree prune`,
+    { signal: opts?.signal, timeoutMs: 10_000 },
+  ).catch(() => {});
+  await sql`UPDATE worktrees SET status = 'archived' WHERE id = ${worktree.id}`.catch(() => {});
+}
+
+/**
+ * v2.6 Phase 3 (3.3): the chat-close cleanup. Mark every `agent_sessions` row for
+ * the chat 'closed', then — only if this was the session's LAST open chat — remove
+ * the shared session worktree (a worktree is one-per-session, shared across the
+ * session's chat tabs, so closing one tab must not pull the rug from sibling tabs).
+ *
+ * Returns what it did so the route can report it. The actual backend (process /
+ * server-session) teardown is the pool's job (`agentPool.closeChat` +
+ * `backend.closeSession`); this owns the DB + git truth.
+ *
+ * `worktreeRemoved` is false when other open chats remain (worktree kept) OR when
+ * the worktree held work at risk (preflight blocked it — never silently dropped).
+ */
+export interface ChatCloseResult {
+  agentRowsClosed: number;
+  worktreeRemoved: boolean;
+  worktreeAtRisk: boolean;
+}
+
+export async function closeChatBackendState(
+  sql: Sql,
+  chatId: string,
+  opts?: { signal?: AbortSignal; force?: boolean },
+): Promise<ChatCloseResult> {
+  // Resolve the chat's session (and that session's project path) before we touch
+  // anything — a deleted chat row leaves agent_sessions/worktrees pointing nowhere.
+  const [chatRow] = await sql<{ session_id: string | null }[]>`
+    SELECT session_id FROM chats WHERE id = ${chatId}
+  `;
+  // chat row may already be gone (delete fired first); fall back to agent_sessions'
+  // session_id link, which SET NULLs only on session delete, not chat delete.
+  let sessionId = chatRow?.session_id ?? null;
+  if (!sessionId) {
+    const [as] = await sql<{ session_id: string | null }[]>`
+      SELECT session_id FROM agent_sessions WHERE chat_id = ${chatId} AND session_id IS NOT NULL LIMIT 1
+    `;
+    sessionId = as?.session_id ?? null;
+  }
+
+  // Mark this chat's (chat,agent) backend rows closed (idempotent).
+  const closedRows = await sql<{ agent: string }[]>`
+    UPDATE agent_sessions SET status = 'closed'
+    WHERE chat_id = ${chatId} AND status <> 'closed'
+    RETURNING agent
+  `;
+
+  let worktreeRemoved = false;
+  let worktreeAtRisk = false;
+
+  if (sessionId) {
+    // Other open chats still sharing the session worktree? If so, keep it.
+    const openRows = await sql<{ open_count: number }[]>`
+      SELECT COUNT(*)::int AS open_count FROM chats
+      WHERE session_id = ${sessionId} AND status = 'open' AND id <> ${chatId}
+    `;
+    const openCount = openRows[0]?.open_count ?? 0;
+    if (openCount === 0) {
+      const [wt] = await sql<{ id: string; path: string; branch: string | null }[]>`
+        SELECT id, path, branch FROM worktrees
+        WHERE session_id = ${sessionId} AND status = 'active' LIMIT 1
+      `;
+      if (wt) {
+        const projRows = await sql<{ path: string | null }[]>`
+          SELECT p.path FROM sessions s JOIN projects p ON p.id = s.project_id WHERE s.id = ${sessionId}
+        `;
+        const projectPath = projRows[0]?.path ?? null;
+        // Preflight (close-hook semantics): a DELIBERATE chat/session close — the
+        // server's session-delete already ran the full work-at-risk gate
+        // (dirty/unpushed/unmerged) before calling us, and chat-close discards the
+        // tab's staged review intentionally. So here we only block on UNCOMMITTED
+        // working-tree changes (`dirty`) — work the user never even staged into the
+        // review diff. The session branch's own commits (the diff-staging
+        // mechanism) are NOT a block; treating them as "unmerged risk" would make
+        // the worktree un-removable on every real session (the orphan reaper keeps
+        // the full at-risk gate because it runs unattended). `force` skips this.
+        if (!opts?.force) {
+          const risk = await checkWorktreeWorkAtRisk(wt.path, opts);
+          worktreeAtRisk = risk.dirty || risk.error != null;
+        }
+        if (projectPath && (opts?.force || !worktreeAtRisk)) {
+          await removeSessionWorktree(sql, projectPath, wt, opts);
+          worktreeRemoved = true;
+        }
+      }
+    }
+  }
+
+  return { agentRowsClosed: closedRows.length, worktreeRemoved, worktreeAtRisk };
+}
+
+/**
+ * v2.6 Phase 3 (3.5): re-baseline a session's worktree diff after a successful
+ * `apply_pending`. The applied changes were written to the PROJECT ROOT; the
+ * worktree branch still holds the same delta against the ORIGINAL `base_commit`,
+ * so the next turn's `diffWorktree(base_commit...worktree-HEAD)` would re-surface
+ * the already-applied changes as "pending" — a confusing double-count.
+ *
+ * Fix: advance the stored `base_commit` to the worktree's CURRENT HEAD (the
+ * `diffWorktree` path commits the worktree's accumulated changes before diffing,
+ * so HEAD already encodes the applied state). The next turn then diffs against
+ * that, surfacing only edits made AFTER the apply. Idempotent: if the worktree has
+ * no new commits, the base is unchanged.
+ *
+ * Diff-baseline-correctness note (design §7): we re-baseline to the worktree's own
+ * HEAD, NOT to a moving project HEAD — so an out-of-band edit to the project root
+ * after apply doesn't corrupt the baseline. The trade-off is that a manual project
+ * edit isn't reflected as "already there"; acceptable, and matches the stored-base
+ * (not moving-target) decision in §7.
+ */
+export async function rebaselineWorktreeAfterApply(
+  sql: Sql,
+  sessionId: string,
+  opts?: { signal?: AbortSignal },
+): Promise<{ rebaselined: boolean; newBaseCommit: string | null }> {
+  const [wt] = await sql<{ id: string; path: string; base_commit: string | null }[]>`
+    SELECT id, path, base_commit FROM worktrees
+    WHERE session_id = ${sessionId} AND status = 'active' LIMIT 1
+  `;
+  if (!wt) return { rebaselined: false, newBaseCommit: null };
+
+  // Make sure the worktree's accumulated edits are committed so HEAD encodes the
+  // just-applied state (the diff path normally does this, but apply may run with no
+  // prior diff this turn). Commit ONLY when something is staged — NO --allow-empty,
+  // so a re-baseline with no new edits doesn't advance HEAD and stays idempotent.
+  await hostExec(
+    `cd ${shellEscape(wt.path)} && git add -A && ` +
+      `git diff --cached --quiet || ` +
+      `git -c user.email=boocoder@local -c user.name=BooCoder commit -q -m "rebaseline after apply"`,
+    { signal: opts?.signal, timeoutMs: 15_000 },
+  ).catch(() => {});
+
+  const headRes = await hostExec(
+    `git -C ${shellEscape(wt.path)} rev-parse HEAD`,
+    { signal: opts?.signal, timeoutMs: 10_000 },
+  ).catch(() => null);
+  const newBase = headRes && headRes.exitCode === 0 ? headRes.stdout.trim() || null : null;
+  if (!newBase || newBase === wt.base_commit) {
+    return { rebaselined: false, newBaseCommit: wt.base_commit };
+  }
+
+  await sql`UPDATE worktrees SET base_commit = ${newBase} WHERE id = ${wt.id}`;
+  return { rebaselined: true, newBaseCommit: newBase };
+}
+
+// ─── Session-delete work-loss guard ─────────────────────────────────────────
+
+/**
+ * Risk report for a single worktree, returned by checkWorktreeWorkAtRisk.
+ * `atRisk` is the gate the server reads before allowing a session delete.
+ * A git error never silently passes — it forces `atRisk` true and surfaces
+ * the message in `error` (fail-closed).
+ */
+export interface RiskReport {
+  worktreePath: string;
+  branch: string;
+  dirty: boolean;   // uncommitted working-tree changes (incl. untracked)
+  unpushed: number; // commits ahead of upstream, or -1 if no upstream is set
+  unmerged: number; // commits on this branch not in the project default branch
+  atRisk: boolean;  // dirty || unmerged > 0 || (upstream && unpushed > 0) || git error
+  error?: string;   // populated on a git failure; presence forces atRisk
+}
+
+/**
+ * Resolve the project's default branch as a git-usable ref (e.g. "origin/main").
+ *
+ * `refs/remotes/origin/HEAD` lives in the repo's COMMON git dir and is shared
+ * across every linked worktree, so reading it from the session worktree returns
+ * the REMOTE's default branch — never this worktree's own `session-<id>` branch
+ * (that would be `symbolic-ref HEAD`, a different ref). Falls back to probing
+ * common defaults by verified existence when origin/HEAD isn't set (e.g. a repo
+ * that never ran `git remote set-head`). Returns null if none resolve, in which
+ * case the unmerged check is skipped (dirty + unpushed still protect the work).
+ */
+async function detectDefaultBranchRef(
+  worktreePath: string,
+  opts?: { signal?: AbortSignal },
+): Promise<string | null> {
+  const head = await hostExec(
+    `git -C ${shellEscape(worktreePath)} symbolic-ref --short refs/remotes/origin/HEAD`,
+    { signal: opts?.signal, timeoutMs: 10_000 },
+  );
+  if (head.exitCode === 0) {
+    const ref = head.stdout.trim(); // e.g. "origin/main"
+    if (ref) {
+      const verify = await hostExec(
+        `git -C ${shellEscape(worktreePath)} rev-parse --verify --quiet ${shellEscape(ref + '^{commit}')}`,
+        { signal: opts?.signal, timeoutMs: 10_000 },
+      );
+      if (verify.exitCode === 0 && verify.stdout.trim()) return ref;
+    }
+  }
+  // origin/HEAD unset or unresolvable — probe common defaults. Prefer the
+  // remote-tracking ref (always resolvable in a fresh worktree) over the local
+  // head, which may not exist if the default branch lives only in the main tree.
+  for (const cand of ['origin/main', 'origin/master', 'main', 'master']) {
+    const verify = await hostExec(
+      `git -C ${shellEscape(worktreePath)} rev-parse --verify --quiet ${shellEscape(cand + '^{commit}')}`,
+      { signal: opts?.signal, timeoutMs: 10_000 },
+    );
+    if (verify.exitCode === 0 && verify.stdout.trim()) return cand;
+  }
+  return null;
+}
+
+/**
+ * Inspect a worktree for work that would be lost if its session were deleted.
+ * Three checks, all via the audited hostExec + shellEscape path (every
+ * interpolated value — paths, refs — is single-quote-escaped; no bare
+ * interpolation). Any unexpected git failure is treated as at-risk, never a
+ * silent pass.
+ */
+export async function checkWorktreeWorkAtRisk(
+  worktreePath: string,
+  opts?: { signal?: AbortSignal },
+): Promise<RiskReport> {
+  // Branch name — also doubles as the "is this still a git worktree?" probe.
+  const br = await hostExec(
+    `git -C ${shellEscape(worktreePath)} rev-parse --abbrev-ref HEAD`,
+    { signal: opts?.signal, timeoutMs: 10_000 },
+  );
+  if (br.exitCode !== 0) {
+    return {
+      worktreePath,
+      branch: '',
+      dirty: false,
+      unpushed: 0,
+      unmerged: 0,
+      atRisk: true,
+      error: `git rev-parse failed: ${br.stderr.trim() || 'not a git worktree'}`,
+    };
+  }
+  const branch = br.stdout.trim();
+
+  // (a) Uncommitted (dirty working tree, including untracked files).
+  const st = await hostExec(
+    `git -C ${shellEscape(worktreePath)} status --porcelain`,
+    { signal: opts?.signal, timeoutMs: 15_000 },
+  );
+  if (st.exitCode !== 0) {
+    return {
+      worktreePath,
+      branch,
+      dirty: false,
+      unpushed: 0,
+      unmerged: 0,
+      atRisk: true,
+      error: `git status failed: ${st.stderr.trim()}`,
+    };
+  }
+  const dirty = st.stdout.trim().length > 0;
+
+  // (b) Unpushed commits. No upstream configured => work exists only locally;
+  // treat as unpushed-by-definition (-1) rather than an error.
+  const up = await hostExec(
+    `git -C ${shellEscape(worktreePath)} rev-list --count ${shellEscape('@{u}..HEAD')}`,
+    { signal: opts?.signal, timeoutMs: 15_000 },
+  );
+  const unpushed = up.exitCode === 0 ? (parseInt(up.stdout.trim() || '0', 10) || 0) : -1;
+
+  // (c) Unmerged commits — on this branch but not in the project default branch.
+  const defaultRef = await detectDefaultBranchRef(worktreePath, opts);
+  let unmerged = 0;
+  if (defaultRef) {
+    const rl = await hostExec(
+      `git -C ${shellEscape(worktreePath)} rev-list --count ${shellEscape(defaultRef + '..HEAD')}`,
+      { signal: opts?.signal, timeoutMs: 15_000 },
+    );
+    if (rl.exitCode === 0) unmerged = parseInt(rl.stdout.trim() || '0', 10) || 0;
+  }
+
+  // unpushed only contributes when an upstream actually exists. Session branches
+  // (session-<id>) never have one (unpushed === -1), and any real local-only work
+  // there already surfaces as unmerged > 0 — so the no-upstream case adds no
+  // protection, only friction (it flagged every pristine worktree-backed session).
+  // The unpushed > 0 arm stays forward-compatible with P1.5 pushable branches.
+  const hasUpstream = unpushed !== -1;
+  const atRisk = dirty || unmerged > 0 || (hasUpstream && unpushed > 0);
+  return { worktreePath, branch, dirty, unpushed, unmerged, atRisk };
+}
+
+/**
+ * Stash a worktree's uncommitted changes (including untracked, via -u) so the
+ * working tree is clean. Stash entries live in the repo's common git dir, so
+ * they survive worktree-dir removal — this is the recoverable, safe-by-default
+ * escape. Note it only clears the *dirty* risk; unpushed/unmerged commits
+ * remain on the branch, so a re-attempted delete may still block on those.
+ */
+export async function stashWorktree(
+  worktreePath: string,
+  opts?: { signal?: AbortSignal },
+): Promise<{ stashed: boolean; error?: string }> {
+  const r = await hostExec(
+    `git -C ${shellEscape(worktreePath)} stash push -u -m ${shellEscape('boocode: pre-delete stash')}`,
+    { signal: opts?.signal, timeoutMs: 30_000 },
+  );
+  if (r.exitCode !== 0) {
+    return { stashed: false, error: r.stderr.trim() || r.stdout.trim() };
+  }
+  // "No local changes to save" => exit 0, nothing stashed — not an error.
+  const stashed = !/no local changes to save/i.test(r.stdout);
+  return { stashed };
+}
+
 /** Minimal shell escape for paths (single-quote wrapping). */
 function shellEscape(s: string): string {
   // Replace single quotes with escaped version, wrap in single quotes

apps/server/package.json

@@ -87,7 +87,7 @@
     "@modelcontextprotocol/sdk": "^1.29.0",
     "ai": "^6.0.190",
     "fastify": "^4.28.1",
-    "parse5": "^8.0.1",
+    "node-html-markdown": "^1.3.0",
     "postgres": "^3.4.4",
     "ws": "^8.18.0",
     "zod": "^3.23.8"
@@ -99,5 +99,5 @@
     "typescript": "^5.5.0",
     "vitest": "^3.2.4"
   },
-  "license": "AGPL-3.0-only"
+  "license": "MIT"
 }

apps/server/src/config.ts

@@ -25,6 +25,8 @@ const ConfigSchema = z.object({
   // v2.0.5: cheaper model for titles, summaries, labeling. Falls back to
   // session model (auto_name) or DEFAULT_MODEL when unset.
   FAST_MODEL: z.string().optional(),
+  TASK_MODEL_URL: z.string().url().optional(),
+  LLAMA_SIDECAR_URL: z.string().url().optional(),
 });
 
 export type Config = z.infer<typeof ConfigSchema>;

apps/server/src/index.ts

@@ -28,7 +28,7 @@ import { cleanupTruncations } from './services/truncate.js';
 import { loadMcpConfig } from './services/mcp-config.js';
 import { initialize as initMcp, getTools as getMcpTools, shutdown as shutdownMcp } from './services/mcp-client.js';
 import { appendMcpTools } from './services/tools.js';
-import { refreshToolNames } from './services/agents.js';
+import { refreshToolNames, getAgentsForProject } from './services/agents.js';
 
 async function main() {
   const config = loadConfig();
@@ -91,6 +91,20 @@ async function main() {
   }
   app.addHook('onClose', async () => { await shutdownMcp(); });
 
+  // Boot-time guard: if any agent has llama_extra_args but LLAMA_SIDECAR_URL
+  // is unset, fail fast. Silent fallback would defeat per-agent flags.
+  if (!config.LLAMA_SIDECAR_URL) {
+    const { agents } = await getAgentsForProject('');
+    const offending = agents.find(a => a.llama_extra_args && a.llama_extra_args.length > 0);
+    if (offending) {
+      app.log.fatal(
+        { agent: offending.name },
+        `Agent "${offending.name}" has llama_extra_args but LLAMA_SIDECAR_URL is not set`,
+      );
+      process.exit(1);
+    }
+  }
+
   await app.register(fastifyWebsocket);
 
   app.get('/api/health', async () => {

apps/server/src/routes/chats.ts

@@ -4,6 +4,7 @@ import type { Sql } from '../db.js';
 import type { Broker } from '../services/broker.js';
 import type { Chat, Message } from '../types/api.js';
 import { getModelContext } from '../services/model-context.js';
+import { notifyCoderClose } from '../services/coder-notify.js';
 
 const CreateBody = z.object({
   name: z.string().min(1).max(200).optional(),
@@ -167,6 +168,9 @@ export function registerChatRoutes(
           chat_id: id,
           session_id: req.params.id,
         });
+        // Fire-and-forget per archived chat: tear down its warm agent backends
+        // on the coder. Best-effort — never blocks/fails the bulk archive.
+        void notifyCoderClose('chat', id, req.log);
       }
       return { archived: ids.length, ids };
     }
@@ -208,6 +212,9 @@ export function registerChatRoutes(
         chat_id: row.id,
         session_id: row.session_id,
       });
+      // Fire-and-forget: tear down this chat's warm agent backends + (last-chat)
+      // worktree on the coder. Best-effort — never blocks/fails the archive.
+      void notifyCoderClose('chat', row.id, req.log);
       reply.code(204);
       return null;
     }
@@ -248,6 +255,9 @@ export function registerChatRoutes(
         chat_id: row.id,
         session_id: row.session_id,
       });
+      // Fire-and-forget: tear down this chat's warm agent backends + (last-chat)
+      // worktree on the coder. Best-effort — never blocks/fails the delete.
+      void notifyCoderClose('chat', row.id, req.log);
       reply.code(204);
       return null;
     }

apps/server/src/routes/sessions.ts

@@ -3,8 +3,9 @@ import { z } from 'zod';
 import type { Sql } from '../db.js';
 import type { Config } from '../config.js';
 import type { Broker } from '../services/broker.js';
-import type { Session } from '../types/api.js';
+import type { Session, WorktreeRiskReport } from '../types/api.js';
 import { getSetting } from './settings.js';
+import { notifyCoderClose } from '../services/coder-notify.js';
 
 const CreateBody = z.object({
   name: z.string().min(1).max(200).optional(),
@@ -28,9 +29,7 @@ const HtmlArtifactStateZ = z.object({
   title: z.string().max(500),
 });
 
-const WorkspacePaneZ = z.object({
+const PaneKindZ = z.enum([
-  id: z.string().min(1).max(200),
-  kind: z.enum([
   'chat',
   'terminal',
   'coder',
@@ -39,7 +38,11 @@ const WorkspacePaneZ = z.object({
   'settings',
   'markdown_artifact',
   'html_artifact',
-  ]),
+]);
+
+const WorkspacePaneZ = z.object({
+  id: z.string().min(1).max(200),
+  kind: PaneKindZ,
   chatId: z.string().min(1).max(200).optional(),
   chatIds: z.array(z.string().min(1).max(200)).max(50),
   activeChatIdx: z.number().int(),
@@ -47,8 +50,27 @@ const WorkspacePaneZ = z.object({
   html_artifact_state: HtmlArtifactStateZ.optional(),
 });
 
+// v2.6.x: workspace_panes column widened from a bare WorkspacePane[] to a
+// WorkspaceState envelope (panes + stable session-scoped tab numbering +
+// reopen stack). closedPaneStack entries are lighter than full panes — just
+// the kind + chat ids needed to recreate a closed pane on reopen.
+const ClosedPaneEntryZ = z.object({
+  kind: PaneKindZ,
+  chatIds: z.array(z.string().min(1).max(200)).max(50),
+  activeChatIdx: z.number().int(),
+});
+
+const WorkspaceStateZ = z.object({
+  panes: z.array(WorkspacePaneZ).max(10),
+  tabNumbers: z.record(z.string(), z.number().int()).default({}),
+  nextTabNumber: z.number().int().default(1),
+  closedPaneStack: z.array(ClosedPaneEntryZ).max(10).default([]),
+});
+
+// Accept either the legacy bare array OR the envelope. The handler normalizes
+// to a full envelope before storing (see MIGRATION rule in the PATCH handler).
 const WorkspacePanesBody = z.object({
-  workspace_panes: z.array(WorkspacePaneZ).max(10),
+  workspace_panes: z.union([z.array(WorkspacePaneZ).max(10), WorkspaceStateZ]),
 });
 
 const PatchBody = z.object({
@@ -308,12 +330,20 @@ export function registerSessionRoutes(
         reply.code(400);
         return { error: 'invalid body', details: parsed.error.flatten() };
       }
-      const workspacePanes = parsed.data.workspace_panes.map((pane) =>
+      // v2.6.x MIGRATION: the body is either a legacy bare WorkspacePane[] or
+      // the WorkspaceState envelope. Normalize to a full envelope so the column
+      // always stores the envelope shape going forward.
+      const body = parsed.data.workspace_panes;
+      const envelope = Array.isArray(body)
+        ? { panes: body, tabNumbers: {}, nextTabNumber: 1, closedPaneStack: [] }
+        : body;
+      // agent → coder normalization on the panes array (unchanged write rule).
+      envelope.panes = envelope.panes.map((pane) =>
         pane.kind === 'agent' ? { ...pane, kind: 'coder' as const } : pane,
       );
       const rows = await sql<Session[]>`
         UPDATE sessions
-        SET workspace_panes = ${sql.json(workspacePanes as never)},
+        SET workspace_panes = ${sql.json(envelope as never)},
             updated_at = clock_timestamp()
         WHERE id = ${req.params.id}
         RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at,
@@ -426,10 +456,55 @@ export function registerSessionRoutes(
     }
   );
 
-  app.delete<{ Params: { id: string } }>(
+  app.delete<{ Params: { id: string }; Querystring: { force?: string } }>(
     '/api/sessions/:id',
     async (req, reply) => {
       const id = req.params.id;
+      const force = req.query.force === 'true' || req.query.force === '1';
+
+      // Session-delete work-loss guard. The check MUST run BEFORE the DELETE:
+      // worktrees.session_id is ON DELETE SET NULL (P1.5-b), so once the session
+      // is gone the worktree rows no longer point back to it — read them while
+      // the link still exists.
+      //
+      // Optimization: read worktrees (P1.5-b — was session_worktrees) from our
+      // own (shared) DB first. No row => chat-only session => nothing on disk =>
+      // delete immediately, zero round-trip. Only worktree-backed sessions pay
+      // the host git check.
+      if (!force) {
+        const worktrees = await sql<{ path: string }[]>`
+          SELECT path FROM worktrees WHERE session_id = ${id}
+        `;
+        if (worktrees.length > 0) {
+          // Worktree dirs live on the host; only BooCoder can run git on them.
+          const origin = process.env.BOOCODER_URL ?? 'http://boocoder:3000';
+          let reports: WorktreeRiskReport[];
+          try {
+            const res = await fetch(`${origin}/api/sessions/${id}/worktree-risk`);
+            if (!res.ok) {
+              // Fail-closed: can't verify => don't risk silent loss. Force escapes.
+              reply.code(409);
+              return {
+                error: 'could not verify worktree safety (BooCoder check failed). Use force to delete anyway.',
+                reports: [] as WorktreeRiskReport[],
+              };
+            }
+            reports = ((await res.json()) as { reports?: WorktreeRiskReport[] }).reports ?? [];
+          } catch {
+            // Fail-closed: BooCoder unreachable. Force bypasses this path entirely.
+            reply.code(409);
+            return {
+              error: 'BooCoder unreachable; cannot verify worktree safety. Use force to delete anyway.',
+              reports: [] as WorktreeRiskReport[],
+            };
+          }
+          if (reports.some((r) => r.atRisk)) {
+            reply.code(409);
+            return { error: 'This session has work at risk in its worktree.', reports };
+          }
+        }
+      }
+
       const deleted = await sql<{ project_id: string }[]>`
         DELETE FROM sessions WHERE id = ${id} RETURNING project_id
       `;
@@ -439,6 +514,10 @@ export function registerSessionRoutes(
       }
       const project_id = deleted[0]!.project_id;
       broker.publishUserFrame('default', { type: 'session_deleted', session_id: id, project_id });
+      // Fire-and-forget: ask BooCoder to tear down this session's warm agent
+      // backends + worktree immediately. Best-effort — never blocks/fails the
+      // delete; the coder's idle-evict + orphan reaper backstop a missed call.
+      void notifyCoderClose('session', id, req.log);
       reply.code(204);
       return null;
     }

apps/server/src/schema.sql

@@ -344,6 +344,7 @@ INSERT INTO settings (key, value) VALUES ('theme_mode', '"dark"') ON CONFLICT (k
 ALTER TABLE projects ADD COLUMN IF NOT EXISTS default_system_prompt TEXT NOT NULL DEFAULT '';
 ALTER TABLE projects ADD COLUMN IF NOT EXISTS default_web_search_enabled BOOLEAN NOT NULL DEFAULT false;
 ALTER TABLE sessions ADD COLUMN IF NOT EXISTS web_search_enabled BOOLEAN;
+ALTER TABLE sessions ADD COLUMN IF NOT EXISTS tags TEXT[] DEFAULT '{}';
 
 -- v1.11: anchored rolling compaction.
 --   compacted_at  — marks rows that are "behind the curtain" of the latest
@@ -366,3 +367,39 @@ ALTER TABLE messages ADD COLUMN IF NOT EXISTS summary BOOLEAN NOT NULL DEFAULT F
 ALTER TABLE messages ADD COLUMN IF NOT EXISTS tail_start_id UUID REFERENCES messages(id) ON DELETE SET NULL;
 ALTER TABLE chats ADD COLUMN IF NOT EXISTS needs_compaction BOOLEAN NOT NULL DEFAULT FALSE;
 CREATE INDEX IF NOT EXISTS idx_messages_chat_compacted ON messages (chat_id, compacted_at);
+
+-- tasks table (provider dispatch, arena)
+CREATE TABLE IF NOT EXISTS tasks (
+  id                UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  project_id        UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
+  session_id        UUID REFERENCES sessions(id) ON DELETE CASCADE,
+  parent_task_id    UUID REFERENCES tasks(id),
+  arena_id          UUID,
+  state             TEXT NOT NULL DEFAULT 'pending'
+                    CHECK (state IN ('pending','running','completed','failed','blocked','cancelled')),
+  input             TEXT NOT NULL,
+  output_summary    TEXT,
+  agent             TEXT,
+  model             TEXT,
+  mode_id           TEXT,
+  thinking_option_id TEXT,
+  feature_values    JSONB,
+  execution_path    TEXT CHECK (execution_path IS NULL OR execution_path IN ('native','acp','pty','qwen')),
+  worktree_path     TEXT,
+  cost_tokens       INTEGER,
+  started_at        TIMESTAMPTZ,
+  ended_at          TIMESTAMPTZ,
+  created_at        TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+
+-- Fix tasks FK to cascade on session delete (existing tables without CASCADE)
+DO $$ BEGIN
+  IF EXISTS (
+    SELECT 1 FROM pg_constraint WHERE conname = 'tasks_session_id_fkey'
+    AND confdeltype != 'c'
+  ) THEN
+    ALTER TABLE tasks DROP CONSTRAINT tasks_session_id_fkey;
+    ALTER TABLE tasks ADD CONSTRAINT tasks_session_id_fkey
+      FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE CASCADE;
+  END IF;
+END $$;

apps/server/src/services/__tests__/agent-allowlist.test.ts

@@ -0,0 +1,107 @@
+import { describe, it, expect } from 'vitest';
+import { parseAgentsMd, matchToolGlob } from '../agents.js';
+import { toolJsonSchemas } from '../tools.js';
+
+describe('agent tool allowlist', () => {
+  const plannerMd = `# Agents
+
+## Planner
+---
+temperature: 0.6
+tools: [view_file, grep, list_dir, find_files]
+description: Read-only planner
+---
+You plan.
+`;
+
+  it('parses an agent with a restricted tool allowlist', () => {
+    const { agents, errors } = parseAgentsMd(plannerMd);
+    expect(errors).toHaveLength(0);
+    expect(agents).toHaveLength(1);
+    const planner = agents[0]!;
+    expect(planner.name).toBe('Planner');
+    expect(planner.tools).toEqual(['view_file', 'grep', 'list_dir', 'find_files']);
+  });
+
+  it('stream-phase filter: agent allowlist excludes tools not in the list', () => {
+    const { agents } = parseAgentsMd(plannerMd);
+    const planner = agents[0]!;
+    const allSchemas = toolJsonSchemas();
+    const filtered = allSchemas.filter((t) =>
+      matchToolGlob(t.function.name, planner.tools),
+    );
+    const filteredNames = filtered.map((t) => t.function.name);
+    expect(filteredNames).toContain('view_file');
+    expect(filteredNames).toContain('grep');
+    expect(filteredNames).not.toContain('edit_file');
+    expect(filteredNames).not.toContain('web_search');
+    expect(filteredNames).not.toContain('get_codebase_overview');
+    expect(filtered).toHaveLength(4);
+  });
+
+  it('tool-phase guard: rejects tool call not in agent allowlist', () => {
+    const { agents } = parseAgentsMd(plannerMd);
+    const planner = agents[0]!;
+    expect(matchToolGlob('edit_file', planner.tools)).toBe(false);
+    expect(matchToolGlob('create_file', planner.tools)).toBe(false);
+    expect(matchToolGlob('delete_file', planner.tools)).toBe(false);
+    expect(matchToolGlob('web_search', planner.tools)).toBe(false);
+  });
+
+  it('tool-phase guard: allows tool call in agent allowlist', () => {
+    const { agents } = parseAgentsMd(plannerMd);
+    const planner = agents[0]!;
+    expect(matchToolGlob('view_file', planner.tools)).toBe(true);
+    expect(matchToolGlob('grep', planner.tools)).toBe(true);
+    expect(matchToolGlob('list_dir', planner.tools)).toBe(true);
+    expect(matchToolGlob('find_files', planner.tools)).toBe(true);
+  });
+
+  it('null/absent tools field defaults to all tools (no regression)', () => {
+    const noToolsMd = `# Agents
+
+## Default
+---
+temperature: 0.7
+description: Uses all tools
+---
+Default agent.
+`;
+    const { agents } = parseAgentsMd(noToolsMd);
+    const agent = agents[0]!;
+    const allSchemas = toolJsonSchemas();
+    const filtered = allSchemas.filter((t) =>
+      matchToolGlob(t.function.name, agent.tools),
+    );
+    expect(filtered.length).toBe(allSchemas.length);
+  });
+
+  it('builder agent: write tools filtered out when not in ALL_TOOLS (BooChat context)', () => {
+    const builderMd = `# Agents
+
+## Builder
+---
+temperature: 0.6
+tools: [view_file, grep, list_dir, find_files, edit_file, create_file, delete_file, apply_pending, rewind]
+description: Read and write tools
+---
+You build.
+`;
+    const { agents } = parseAgentsMd(builderMd);
+    const builder = agents[0]!;
+    expect(matchToolGlob('view_file', builder.tools)).toBe(true);
+    expect(matchToolGlob('grep', builder.tools)).toBe(true);
+    // Write tools not in server's ALL_TOOLS are silently filtered during parsing.
+    // In BooCoder context (where ALL_TOOLS includes write tools), they'd be retained.
+    expect(builder.tools).not.toContain('edit_file');
+    expect(builder.tools).not.toContain('create_file');
+    expect(matchToolGlob('web_search', builder.tools)).toBe(false);
+  });
+
+  it('matchToolGlob rejects hallucinated tool against exact allowlist', () => {
+    const allowlist = ['view_file', 'grep', 'list_dir'];
+    expect(matchToolGlob('edit_file', allowlist)).toBe(false);
+    expect(matchToolGlob('rm_rf', allowlist)).toBe(false);
+    expect(matchToolGlob('view_file_extended', allowlist)).toBe(false);
+  });
+});

apps/server/src/services/__tests__/agents.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect, vi, afterEach } from 'vitest';
 import { isAgentRegistryMarkdown, parseAgentsMd } from '../agents.js';
 
 describe('isAgentRegistryMarkdown', () => {
@@ -31,3 +31,87 @@ Start here
     expect(r.errors.length).toBeGreaterThan(0);
   });
 });
+
+// v2.6 sampling-streamjson-tokens (#11): per-agent llama.cpp sampler extensions.
+describe('parseAgentsMd: v2.6 sampling knobs', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  const withFrontmatter = (lines: string) => `# Agents
+
+## Sampler
+---
+temperature: 0.6
+${lines}
+tools: [view_file]
+description: test
+---
+You sample.
+`;
+
+  it('parses top_n_sigma and the dry_* family from frontmatter', () => {
+    const md = withFrontmatter(
+      [
+        'top_n_sigma: 1.5',
+        'dry_multiplier: 0.8',
+        'dry_base: 1.75',
+        'dry_allowed_length: 2',
+        'dry_penalty_last_n: -1',
+      ].join('\n'),
+    );
+    const { agents, errors } = parseAgentsMd(md);
+    expect(errors).toHaveLength(0);
+    expect(agents).toHaveLength(1);
+    const a = agents[0]!;
+    expect(a.top_n_sigma).toBe(1.5);
+    expect(a.dry_multiplier).toBe(0.8);
+    expect(a.dry_base).toBe(1.75);
+    expect(a.dry_allowed_length).toBe(2);
+    expect(a.dry_penalty_last_n).toBe(-1);
+  });
+
+  it('defaults the new sampler fields to null when omitted', () => {
+    const { agents } = parseAgentsMd(withFrontmatter('top_p: 0.95'));
+    const a = agents[0]!;
+    expect(a.top_n_sigma).toBeNull();
+    expect(a.dry_multiplier).toBeNull();
+    expect(a.dry_base).toBeNull();
+    expect(a.dry_allowed_length).toBeNull();
+    expect(a.dry_penalty_last_n).toBeNull();
+  });
+
+  it('warns (does not error) on out-of-range top_n_sigma / dry_* values', () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    const md = withFrontmatter(
+      [
+        'top_n_sigma: -1',
+        'dry_multiplier: -0.5',
+        'dry_base: -2',
+        'dry_allowed_length: -3',
+        'dry_penalty_last_n: -5',
+      ].join('\n'),
+    );
+    const { agents, errors } = parseAgentsMd(md);
+    expect(errors).toHaveLength(0);
+    expect(agents).toHaveLength(1);
+    // Mirrors top_k/min_p: out-of-range still stored, with a warning.
+    expect(warn).toHaveBeenCalled();
+    const warnings = warn.mock.calls.map((c) => String(c[0])).join('\n');
+    expect(warnings).toContain('top_n_sigma');
+    expect(warnings).toContain('dry_multiplier');
+    expect(warnings).toContain('dry_base');
+    expect(warnings).toContain('dry_allowed_length');
+    expect(warnings).toContain('dry_penalty_last_n');
+  });
+
+  it('errors on non-numeric / non-integer sampler values', () => {
+    const md = withFrontmatter(
+      ['top_n_sigma: high', 'dry_allowed_length: 2.5'].join('\n'),
+    );
+    const { errors } = parseAgentsMd(md);
+    const joined = errors.map((e) => e.reason).join('\n');
+    expect(joined).toContain('top_n_sigma must be a number');
+    expect(joined).toContain('dry_allowed_length must be an integer');
+  });
+});

apps/server/src/services/__tests__/coder-notify.test.ts

@@ -0,0 +1,67 @@
+// v2.6.10 Phase 3 (server wiring) — notifyCoderClose fire-and-forget helper.
+//
+// The guarantee under test: the helper NEVER throws (so it can't break the
+// user's delete/archive path), targets the correct coder URL shape, and folds
+// every failure mode (non-2xx, network error) into a `false` result.
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { notifyCoderClose } from '../coder-notify.js';
+
+const ORIGINAL_BOOCODER_URL = process.env.BOOCODER_URL;
+
+describe('notifyCoderClose', () => {
+  beforeEach(() => {
+    delete process.env.BOOCODER_URL;
+  });
+  afterEach(() => {
+    if (ORIGINAL_BOOCODER_URL === undefined) delete process.env.BOOCODER_URL;
+    else process.env.BOOCODER_URL = ORIGINAL_BOOCODER_URL;
+  });
+
+  it('POSTs the chat close hook at the default coder origin and resolves true on 2xx', async () => {
+    const fetcher = vi.fn().mockResolvedValue(new Response(null, { status: 200 }));
+    const ok = await notifyCoderClose('chat', 'chat-123', undefined, fetcher as unknown as typeof fetch);
+    expect(ok).toBe(true);
+    expect(fetcher).toHaveBeenCalledTimes(1);
+    const [url, init] = fetcher.mock.calls[0]!;
+    expect(url).toBe('http://boocoder:3000/api/chats/chat-123/close');
+    expect(init).toEqual({ method: 'POST' });
+  });
+
+  it('POSTs the session close hook with the sessions segment', async () => {
+    const fetcher = vi.fn().mockResolvedValue(new Response(null, { status: 200 }));
+    const ok = await notifyCoderClose('session', 'sess-abc', undefined, fetcher as unknown as typeof fetch);
+    expect(ok).toBe(true);
+    expect(fetcher.mock.calls[0]![0]).toBe('http://boocoder:3000/api/sessions/sess-abc/close');
+  });
+
+  it('honors BOOCODER_URL for the origin', async () => {
+    process.env.BOOCODER_URL = 'http://100.114.205.53:9502';
+    const fetcher = vi.fn().mockResolvedValue(new Response(null, { status: 200 }));
+    await notifyCoderClose('chat', 'c1', undefined, fetcher as unknown as typeof fetch);
+    expect(fetcher.mock.calls[0]![0]).toBe('http://100.114.205.53:9502/api/chats/c1/close');
+  });
+
+  it('resolves false on a non-2xx response (does not throw)', async () => {
+    const fetcher = vi.fn().mockResolvedValue(new Response(null, { status: 500 }));
+    const log = { debug: vi.fn() };
+    const ok = await notifyCoderClose('chat', 'c1', log, fetcher as unknown as typeof fetch);
+    expect(ok).toBe(false);
+    expect(log.debug).toHaveBeenCalledTimes(1);
+  });
+
+  it('resolves false on a network error (coder unreachable) — never rejects', async () => {
+    const fetcher = vi.fn().mockRejectedValue(new Error('ECONNREFUSED'));
+    const log = { debug: vi.fn() };
+    const ok = await notifyCoderClose('session', 's1', log, fetcher as unknown as typeof fetch);
+    expect(ok).toBe(false);
+    expect(log.debug).toHaveBeenCalledTimes(1);
+  });
+
+  it('does not require a logger', async () => {
+    const fetcher = vi.fn().mockRejectedValue(new Error('boom'));
+    await expect(
+      notifyCoderClose('chat', 'c1', undefined, fetcher as unknown as typeof fetch),
+    ).resolves.toBe(false);
+  });
+});

apps/server/src/services/__tests__/html-to-md.test.ts

@@ -70,10 +70,16 @@ describe('htmlToMarkdown', () => {
         </tbody>
       </table>`;
     const md = htmlToMarkdown(html);
-    expect(md).toContain('| Name | Age | City |');
+    // node-html-markdown pads columns to align them; assert structure rather
-    expect(md).toContain('| --- | --- | --- |');
+    // than exact spacing. Each cell value and a GFM separator row are present.
-    expect(md).toContain('| Alice | 30 | NYC |');
+    expect(md).toContain('| Name ');
-    expect(md).toContain('| Bob | 25 | LA |');
+    expect(md).toContain('| Age ');
+    expect(md).toContain('| City |');
+    expect(md).toMatch(/\| -+ \| -+ \| -+ \|/); // separator row
+    expect(md).toContain('| Alice ');
+    expect(md).toContain('| NYC  |');
+    expect(md).toContain('| Bob   ');
+    expect(md).toContain('| LA   |');
   });
 
   it('escapes pipe characters in table cells', () => {
@@ -162,14 +168,17 @@ describe('htmlToMarkdown', () => {
 
   it('converts br to newline', () => {
     const md = htmlToMarkdown('line one<br>line two');
-    expect(md).toContain('line one\nline two');
+    // node-html-markdown emits a GFM hard line break (trailing two spaces).
+    expect(md).toContain('line one  \nline two');
   });
 
   it('handles ol with start attribute', () => {
     const html = '<ol start="5"><li>five</li><li>six</li></ol>';
     const md = htmlToMarkdown(html);
-    expect(md).toContain('5. five');
+    // node-html-markdown does not honor the `start` attribute; it always
-    expect(md).toContain('6. six');
+    // renumbers ordered lists from 1. (Old parse5 renderer honored start=.)
+    expect(md).toContain('1. five');
+    expect(md).toContain('2. six');
   });
 
   it('collapses excessive blank lines', () => {
@@ -212,9 +221,12 @@ describe('htmlToMarkdown', () => {
     expect(md).toContain('[a link](https://example.com)');
     expect(md).toContain('## Features');
     expect(md).toContain('* Fast');
-    expect(md).toContain('| Metric | Value |');
+    // Table columns are padded to align (node-html-markdown behavior).
-    expect(md).toContain('| --- | --- |');
+    expect(md).toContain('| Metric ');
-    expect(md).toContain('| Uptime | 99.9% |');
+    expect(md).toContain('| Value |');
+    expect(md).toMatch(/\| -+ \| -+ \|/); // separator row
+    expect(md).toContain('| Uptime ');
+    expect(md).toContain('| 99.9% |');
     expect(md).toContain('> This tool is amazing.');
     expect(md).toContain('```js\nconsole.log("hello");\n```');
     expect(md).not.toContain('evil');

apps/server/src/services/__tests__/license-mit.test.ts

@@ -0,0 +1,46 @@
+import { describe, expect, it } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, resolve } from 'node:path';
+
+// Guards the AGPL-3.0 -> MIT relicense (openspec license-debt-mit). If any of
+// these fail, AGPL-derived provenance has crept back in.
+const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '../../../../..');
+
+describe('license: MIT relicense guard', () => {
+  it('LICENSE is MIT (no Affero/AGPL text)', () => {
+    const license = readFileSync(resolve(ROOT, 'LICENSE'), 'utf8');
+    expect(license).toMatch(/^MIT License/);
+    expect(license).not.toMatch(/AFFERO|AGPL/i);
+  });
+
+  const PACKAGE_JSONS = [
+    'package.json',
+    'apps/server/package.json',
+    'apps/web/package.json',
+    'apps/coder/package.json',
+    'apps/booterm/package.json',
+  ];
+  for (const rel of PACKAGE_JSONS) {
+    it(`${rel} declares "license": "MIT"`, () => {
+      const pkg = JSON.parse(readFileSync(resolve(ROOT, rel), 'utf8')) as { license?: string };
+      expect(pkg.license).toBe('MIT');
+    });
+  }
+
+  // The three files that were ported from Unsloth Studio (AGPL-3.0-only) and
+  // cleared in this batch — they must carry no AGPL/Unsloth provenance.
+  const FORMERLY_AGPL = [
+    'apps/server/src/services/inference/tool-call-parser.ts',
+    'apps/server/src/services/web/html-to-md.ts',
+    'apps/server/src/services/inference/llama-args-validator.ts',
+  ];
+  for (const rel of FORMERLY_AGPL) {
+    it(`${rel} carries no AGPL / Unsloth provenance`, () => {
+      const src = readFileSync(resolve(ROOT, rel), 'utf8');
+      expect(src).not.toMatch(/AGPL/);
+      expect(src).not.toMatch(/SPDX-License-Identifier:\s*AGPL/);
+      expect(src).not.toMatch(/Unsloth/i);
+    });
+  }
+});

apps/server/src/services/__tests__/provider.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, it } from 'vitest';
+import { resolveRoute, upstreamModel } from '../inference/provider.js';
+
+describe('resolveRoute', () => {
+  it('routes to swap when agent is null', () => {
+    expect(resolveRoute(null)).toEqual({ route: 'swap', flags: null });
+  });
+
+  it('routes to swap when agent has no llama_extra_args', () => {
+    expect(resolveRoute({ llama_extra_args: null })).toEqual({ route: 'swap', flags: null });
+  });
+
+  it('routes to swap when agent has empty llama_extra_args', () => {
+    expect(resolveRoute({ llama_extra_args: [] })).toEqual({ route: 'swap', flags: null });
+  });
+
+  it('routes to sidecar when agent has llama_extra_args', () => {
+    const result = resolveRoute({ llama_extra_args: ['--top-k', '20'] });
+    expect(result.route).toBe('sidecar');
+    expect(result.flags).toEqual(['--top-k', '20']);
+  });
+});
+
+describe('upstreamModel', () => {
+  const swapConfig = { LLAMA_SWAP_URL: 'http://localhost:8401' };
+  const fullConfig = {
+    LLAMA_SWAP_URL: 'http://localhost:8401',
+    LLAMA_SIDECAR_URL: 'http://localhost:8402',
+  };
+
+  it('returns a model for swap route (no agent)', () => {
+    const model = upstreamModel(swapConfig, 'test-model');
+    expect(model).toBeDefined();
+    expect((model as any).modelId).toBe('test-model');
+  });
+
+  it('returns a model for swap route (agent without extra args)', () => {
+    const model = upstreamModel(swapConfig, 'test-model', { llama_extra_args: null });
+    expect(model).toBeDefined();
+  });
+
+  it('returns a model for sidecar route', () => {
+    const model = upstreamModel(fullConfig, 'test-model', { llama_extra_args: ['--top-k', '20'] });
+    expect(model).toBeDefined();
+    expect((model as any).modelId).toBe('test-model');
+  });
+
+  it('throws when sidecar route requested but URL missing', () => {
+    expect(() =>
+      upstreamModel(swapConfig, 'test-model', { llama_extra_args: ['--top-k', '20'] }),
+    ).toThrow(/LLAMA_SIDECAR_URL/);
+  });
+
+  it('routes to swap for empty llama_extra_args array', () => {
+    const model = upstreamModel(swapConfig, 'test-model', { llama_extra_args: [] });
+    expect(model).toBeDefined();
+  });
+});

apps/server/src/services/__tests__/tool-call-parser.test.ts

@@ -4,18 +4,11 @@ import {
   parseInvokeToolCall,
   partialXmlOpenerStart,
   extractToolCallBlocks,
-  parseToolCallsFromText,
   stripToolMarkup,
-  hasToolSignal,
   XML_TOOL_OPEN,
   XML_TOOL_CLOSE,
   INVOKE_TOOL_OPEN,
   INVOKE_TOOL_CLOSE,
-  TOOL_XML_SIGNALS,
-  BUDGET_EXHAUSTED_NUDGE,
-  DUPLICATE_CALL_NUDGE,
-  TOOL_ERROR_NUDGE,
-  TOOL_ERROR_PREFIXES,
 } from '../inference/tool-call-parser.js';
 
 // ── Ported from xml-parser.test.ts ───────────────────────────────────────
@@ -301,38 +294,6 @@ describe('extractToolCallBlocks (v1.13.16 — unified extraction)', () => {
   });
 });
 
-// ── New tests: Unsloth-ported functions ──────────────────────────────────
-
-describe('hasToolSignal', () => {
-  it('returns true for <tool_call>', () => {
-    expect(hasToolSignal('prefix <tool_call> suffix')).toBe(true);
-  });
-
-  it('returns true for <function=', () => {
-    expect(hasToolSignal('prefix <function=view_file> suffix')).toBe(true);
-  });
-
-  it('returns true for <invoke', () => {
-    expect(hasToolSignal('prefix <invoke name="x"> suffix')).toBe(true);
-  });
-
-  it('returns false for near-miss <tool>', () => {
-    expect(hasToolSignal('prefix <tool> suffix')).toBe(false);
-  });
-
-  it('returns false for near-miss <function>', () => {
-    expect(hasToolSignal('prefix <function> suffix')).toBe(false);
-  });
-
-  it('returns false for near-miss <tool_call_thing>', () => {
-    expect(hasToolSignal('<tool_call_thing>')).toBe(false);
-  });
-
-  it('returns false for plain text', () => {
-    expect(hasToolSignal('just some text')).toBe(false);
-  });
-});
-
 describe('stripToolMarkup', () => {
   it('strips closed <tool_call> blocks', () => {
     const input = 'before <tool_call>{"name":"x"}</tool_call> after';
@@ -380,166 +341,11 @@ describe('stripToolMarkup', () => {
   });
 });
 
-describe('parseToolCallsFromText', () => {
+describe('delimiter constants', () => {
-  describe('pattern 1: <tool_call>{json}</tool_call>', () => {
+  it('exports the expected delimiters', () => {
-    it('parses a well-formed JSON tool call', () => {
+    expect(INVOKE_TOOL_OPEN).toBe('<invoke');
-      const input = '<tool_call>{"name":"web_search","arguments":{"query":"hello"}}</tool_call>';
+    expect(INVOKE_TOOL_CLOSE).toBe('</invoke>');
-      const calls = parseToolCallsFromText(input);
+    expect(XML_TOOL_OPEN).toBe('<tool_call>');
-      expect(calls).toHaveLength(1);
+    expect(XML_TOOL_CLOSE).toBe('</tool_call>');
-      expect(calls[0]!.id).toBe('call_0');
-      expect(calls[0]!.type).toBe('function');
-      expect(calls[0]!.function.name).toBe('web_search');
-      expect(JSON.parse(calls[0]!.function.arguments)).toEqual({ query: 'hello' });
-    });
-
-    it('handles string arguments field', () => {
-      const input = '<tool_call>{"name":"x","arguments":"already a string"}</tool_call>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls[0]!.function.arguments).toBe('already a string');
-    });
-
-    it('handles balanced braces inside JSON strings', () => {
-      const input = '<tool_call>{"name":"x","arguments":{"q":"} { extra "}}</tool_call>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      const parsed = JSON.parse(calls[0]!.function.arguments);
-      expect(parsed.q).toBe('} { extra ');
-    });
-
-    it('respects idOffset', () => {
-      const input = '<tool_call>{"name":"a","arguments":{}}</tool_call>';
-      const calls = parseToolCallsFromText(input, { idOffset: 5 });
-      expect(calls[0]!.id).toBe('call_5');
-    });
-
-    it('parses multiple JSON tool calls', () => {
-      const input =
-        '<tool_call>{"name":"a","arguments":{}}</tool_call>' +
-        '<tool_call>{"name":"b","arguments":{}}</tool_call>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(2);
-      expect(calls[0]!.id).toBe('call_0');
-      expect(calls[1]!.id).toBe('call_1');
-    });
-
-    it('skips malformed JSON', () => {
-      const input = '<tool_call>{not json}</tool_call>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(0);
-    });
-
-    it('handles missing closing tag', () => {
-      const input = '<tool_call>{"name":"x","arguments":{"q":"hello"}}';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('x');
-    });
-  });
-
-  describe('pattern 2: <function=name><parameter=key>value', () => {
-    it('parses a single-parameter function call', () => {
-      const input = '<function=view_file><parameter=path>/tmp/foo</parameter></function>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('view_file');
-      expect(JSON.parse(calls[0]!.function.arguments)).toEqual({ path: '/tmp/foo' });
-    });
-
-    it('single-param fast path preserves embedded </parameter>', () => {
-      const input = '<function=run_bash><parameter=command>echo "</parameter>"</parameter></function>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(JSON.parse(calls[0]!.function.arguments).command).toBe('echo "</parameter>"');
-    });
-
-    it('multi-param: value of first stops at start of second', () => {
-      const input = '<function=grep><parameter=pattern>foo</parameter><parameter=path>src/</parameter></function>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      const args = JSON.parse(calls[0]!.function.arguments);
-      expect(args.pattern).toBe('foo');
-      expect(args.path).toBe('src/');
-    });
-
-    it('tolerates missing closing tags', () => {
-      const input = '<function=view_file><parameter=path>/tmp/foo';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('view_file');
-      expect(JSON.parse(calls[0]!.function.arguments)).toEqual({ path: '/tmp/foo' });
-    });
-
-    it('does not fire when pattern 1 found results', () => {
-      const input = '<tool_call>{"name":"a","arguments":{}}</tool_call><function=b><parameter=x>y</parameter></function>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('a');
-    });
-  });
-
-  describe('pattern 3: <invoke name="..."><parameter name="...">value (Anthropic)', () => {
-    it('parses a single-parameter invoke call', () => {
-      const input = '<invoke name="view_file"><parameter name="path">/tmp/foo</parameter></invoke>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('view_file');
-      expect(JSON.parse(calls[0]!.function.arguments)).toEqual({ path: '/tmp/foo' });
-    });
-
-    it('parses multi-parameter invoke call', () => {
-      const input = '<invoke name="grep"><parameter name="pattern">foo</parameter><parameter name="path">src/</parameter></invoke>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      const args = JSON.parse(calls[0]!.function.arguments);
-      expect(args.pattern).toBe('foo');
-      expect(args.path).toBe('src/');
-    });
-
-    it('does not fire when pattern 1 found results', () => {
-      const input = '<tool_call>{"name":"a","arguments":{}}</tool_call><invoke name="b"><parameter name="x">y</parameter></invoke>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('a');
-    });
-
-    it('does not fire when pattern 2 found results', () => {
-      const input = '<function=a><parameter=x>y</parameter></function><invoke name="b"><parameter name="x">y</parameter></invoke>';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('a');
-    });
-
-    it('tolerates missing closing tags', () => {
-      const input = '<invoke name="view_file"><parameter name="path">/tmp/foo';
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(JSON.parse(calls[0]!.function.arguments)).toEqual({ path: '/tmp/foo' });
-    });
-
-    it('supports single-quoted attributes', () => {
-      const input = "<invoke name='view_file'><parameter name='path'>/tmp/foo</parameter></invoke>";
-      const calls = parseToolCallsFromText(input);
-      expect(calls).toHaveLength(1);
-      expect(calls[0]!.function.name).toBe('view_file');
-    });
-  });
-});
-
-describe('constants', () => {
-  it('TOOL_XML_SIGNALS includes all three signal prefixes', () => {
-    expect(TOOL_XML_SIGNALS).toContain('<tool_call>');
-    expect(TOOL_XML_SIGNALS).toContain('<function=');
-    expect(TOOL_XML_SIGNALS).toContain('<invoke');
-  });
-
-  it('nudge constants are non-empty strings', () => {
-    expect(BUDGET_EXHAUSTED_NUDGE.length).toBeGreaterThan(0);
-    expect(DUPLICATE_CALL_NUDGE.length).toBeGreaterThan(0);
-    expect(TOOL_ERROR_NUDGE.length).toBeGreaterThan(0);
-  });
-
-  it('TOOL_ERROR_PREFIXES is a non-empty tuple', () => {
-    expect(TOOL_ERROR_PREFIXES.length).toBeGreaterThan(0);
-    expect(TOOL_ERROR_PREFIXES).toContain('Error');
   });
 });

apps/server/src/services/agents.ts

@@ -88,6 +88,12 @@ interface ParsedFrontmatter {
   top_k?: number;
   min_p?: number;
   presence_penalty?: number;
+  // v2.6 sampling-streamjson-tokens (#11): llama.cpp sampler extensions.
+  top_n_sigma?: number;
+  dry_multiplier?: number;
+  dry_base?: number;
+  dry_allowed_length?: number;
+  dry_penalty_last_n?: number;
   tools?: string[];
   description?: string;
   model?: string;
@@ -178,6 +184,63 @@ function parseFrontmatter(yaml: string): { data: ParsedFrontmatter; errors: stri
       } else {
         errors.push(`presence_penalty must be a number (got "${valueRaw}")`);
       }
+    } else if (key === 'top_n_sigma') {
+      // v2.6 #11: llama.cpp top-n-sigma sampler. Float ≥ 0 (typical 0-3).
+      // Mirrors top_p/min_p: store then warn on out-of-range (non-numeric
+      // hard-fails the block).
+      const n = Number(valueRaw);
+      if (Number.isFinite(n)) {
+        data.top_n_sigma = n;
+        if (n < 0) {
+          console.warn(`agents: top_n_sigma ${n} out of range (≥0), ignoring (falling back to default)`);
+        }
+      } else {
+        errors.push(`top_n_sigma must be a number (got "${valueRaw}")`);
+      }
+    } else if (key === 'dry_multiplier') {
+      // v2.6 #11: DRY repetition-penalty multiplier. Float ≥ 0 (0 disables DRY).
+      const n = Number(valueRaw);
+      if (Number.isFinite(n)) {
+        data.dry_multiplier = n;
+        if (n < 0) {
+          console.warn(`agents: dry_multiplier ${n} out of range (≥0), ignoring (falling back to default)`);
+        }
+      } else {
+        errors.push(`dry_multiplier must be a number (got "${valueRaw}")`);
+      }
+    } else if (key === 'dry_base') {
+      // v2.6 #11: DRY penalty growth base. Float ≥ 0.
+      const n = Number(valueRaw);
+      if (Number.isFinite(n)) {
+        data.dry_base = n;
+        if (n < 0) {
+          console.warn(`agents: dry_base ${n} out of range (≥0), ignoring (falling back to default)`);
+        }
+      } else {
+        errors.push(`dry_base must be a number (got "${valueRaw}")`);
+      }
+    } else if (key === 'dry_allowed_length') {
+      // v2.6 #11: DRY max sequence length not penalized. Integer ≥ 0.
+      const n = Number(valueRaw);
+      if (Number.isInteger(n)) {
+        data.dry_allowed_length = n;
+        if (n < 0) {
+          console.warn(`agents: dry_allowed_length ${n} out of range (≥0), ignoring (falling back to default)`);
+        }
+      } else {
+        errors.push(`dry_allowed_length must be an integer (got "${valueRaw}")`);
+      }
+    } else if (key === 'dry_penalty_last_n') {
+      // v2.6 #11: DRY lookback window. Integer ≥ -1 (-1 = whole context, 0 = off).
+      const n = Number(valueRaw);
+      if (Number.isInteger(n)) {
+        data.dry_penalty_last_n = n;
+        if (n < -1) {
+          console.warn(`agents: dry_penalty_last_n ${n} out of range (≥-1), ignoring (falling back to default)`);
+        }
+      } else {
+        errors.push(`dry_penalty_last_n must be an integer (got "${valueRaw}")`);
+      }
     } else if (key === 'tools') {
       if (valueRaw === '') {
         data.tools = [];
@@ -354,6 +417,11 @@ function parseAgentSection(section: RawSection): Omit<Agent, 'source'> {
     top_k: typeof fm.top_k === 'number' ? fm.top_k : null,
     min_p: typeof fm.min_p === 'number' ? fm.min_p : null,
     presence_penalty: typeof fm.presence_penalty === 'number' ? fm.presence_penalty : null,
+    top_n_sigma: typeof fm.top_n_sigma === 'number' ? fm.top_n_sigma : null,
+    dry_multiplier: typeof fm.dry_multiplier === 'number' ? fm.dry_multiplier : null,
+    dry_base: typeof fm.dry_base === 'number' ? fm.dry_base : null,
+    dry_allowed_length: typeof fm.dry_allowed_length === 'number' ? fm.dry_allowed_length : null,
+    dry_penalty_last_n: typeof fm.dry_penalty_last_n === 'number' ? fm.dry_penalty_last_n : null,
     tools: filteredTools,
     model: typeof fm.model === 'string' && fm.model.length > 0 ? fm.model : null,
     max_tool_calls: typeof fm.max_tool_calls === 'number' ? fm.max_tool_calls : null,

apps/server/src/services/auto_name.ts

@@ -1,9 +1,10 @@
 import type { InferenceContext } from './inference/index.js';
+import { taskModelCompletion } from './task-model.js';
 
 const NAMING_SYSTEM_PROMPT =
-  'You name chat sessions based on what the assistant did. Summarize the topic or outcome — do NOT copy the first few words verbatim. Reply directly with no thinking, reasoning, or explanation. Output ONLY the title, 4 words max, no quotes, no punctuation, no prefix like "Title:".';
+  'You name chat sessions. Reply with ONLY the title. 4 to 6 words. No quotes, no punctuation, no prefix.';
 
-const MAX_TITLE_CHARS = 60;
+const MAX_TITLE_CHARS = 80;
 
 function cleanTitle(raw: string): string {
   let name = raw.trim();
@@ -18,27 +19,7 @@ function cleanTitle(raw: string): string {
   return name;
 }
 
-interface NamingResponse {
+// TODO: wire suggestTags after task model validation
-  choices?: Array<{
-    message?: {
-      content?: string;
-      reasoning_content?: string;
-    };
-  }>;
-}
-
-function pickTitleSource(data: NamingResponse): string {
-  const choice = data.choices?.[0]?.message;
-  if (!choice) return '';
-  if (choice.content && choice.content.trim().length > 0) return choice.content;
-  const reasoning = choice.reasoning_content ?? '';
-  if (reasoning.length === 0) return '';
-  const lines = reasoning
-    .split('\n')
-    .map((l) => l.trim())
-    .filter((l) => l.length > 0);
-  return lines[lines.length - 1] ?? '';
-}
 
 export async function maybeAutoNameChat(
   ctx: InferenceContext,
@@ -56,60 +37,40 @@ export async function maybeAutoNameChat(
   if ((counts[0]?.n ?? 0) < 1) return;
 
   const chatRows = await ctx.sql<
-    { id: string; name: string | null; session_id: string }[]
+    { id: string; name: string | null; session_id: string; model: string | null }[]
   >`
-    SELECT id, name, session_id FROM chats WHERE id = ${chatId}
+    SELECT c.id, c.name, c.session_id, s.model
+    FROM chats c JOIN sessions s ON s.id = c.session_id
+    WHERE c.id = ${chatId}
   `;
   const chat = chatRows[0];
   if (!chat) return;
   if (chat.name !== null && chat.name !== '') return;
 
-  const sessionRows = await ctx.sql<{ model: string }[]>`
+  const firstMsgs = await ctx.sql<{ role: string; content: string }[]>`
-    SELECT model FROM sessions WHERE id = ${sessionId}
+    SELECT role, content FROM messages
-  `;
-  // v2.0.5: prefer FAST_MODEL for cheap LLM calls (titles, summaries).
-  const model = ctx.config.FAST_MODEL ?? sessionRows[0]?.model;
-  if (!model) return;
-
-  const assistantMsg = await ctx.sql<{ content: string }[]>`
-    SELECT content FROM messages
     WHERE chat_id = ${chatId}
-      AND role = 'assistant'
+      AND role IN ('user', 'assistant')
-      AND status = 'complete'
+      AND status IN ('complete', 'ok')
       AND content <> ''
     ORDER BY created_at ASC
-    LIMIT 1
+    LIMIT 2
   `;
-  if (!assistantMsg[0]) return;
+  const userMsg = firstMsgs.find(m => m.role === 'user');
+  const assistantMsg = firstMsgs.find(m => m.role === 'assistant');
+  if (!assistantMsg) return;
 
-  const assistantText = assistantMsg[0].content.slice(0, 2000);
+  let namingInput = '';
+  if (userMsg) namingInput += `User: ${userMsg.content.slice(0, 1000)}\n\n`;
+  namingInput += `Assistant: ${assistantMsg.content.slice(0, 1000)}`;
 
-  const body = {
+  const raw = await taskModelCompletion({
-    model,
+    system: NAMING_SYSTEM_PROMPT,
-    messages: [
+    user: namingInput,
-      { role: 'system', content: NAMING_SYSTEM_PROMPT },
+    maxTokens: 30,
-      {
-        role: 'user',
-        content: assistantText,
-      },
-    ],
-    max_tokens: 30,
     temperature: 0.3,
-    stream: false,
+    fallbackModel: chat.model ?? undefined,
-    chat_template_kwargs: { enable_thinking: false },
-  };
-
-  const res = await fetch(`${ctx.config.LLAMA_SWAP_URL}/v1/chat/completions`, {
-    method: 'POST',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify(body),
   });
-  if (!res.ok) {
-    const text = await res.text().catch(() => '');
-    throw new Error(`naming request failed: ${res.status} ${text.slice(0, 200)}`);
-  }
-  const data = (await res.json()) as NamingResponse;
-  const raw = pickTitleSource(data);
   const name = cleanTitle(raw);
   if (!name) {
     ctx.log.warn({ chatId, raw }, 'auto-name: empty title from model');

apps/server/src/services/coder-notify.ts

@@ -0,0 +1,64 @@
+// v2.6.10 Phase 3 (server wiring) — fire-and-forget BooCoder close hooks.
+//
+// BooCoder (apps/coder, host systemd) added close hooks in
+// apps/coder/src/routes/lifecycle.ts:
+//   POST /api/chats/:chatId/close      — evict the chat's warm (chat,agent)
+//                                        backends, close its opencode session,
+//                                        mark agent_sessions closed, and remove
+//                                        the shared worktree on the last chat.
+//   POST /api/sessions/:sessionId/close — loop the chat-close path for every
+//                                        chat in the session.
+//
+// apps/server (Docker) can't see the host worktree dirs or reach the warm agent
+// processes, so — exactly like the existing `worktree-risk` guard in
+// routes/sessions.ts — it signals the coder over HTTP and the coder does the
+// real teardown. This call is BEST-EFFORT: the coder's idle-pool eviction and
+// the orphan-worktree reaper backstop a missed/failed call. It MUST NEVER block
+// or fail the user's delete/archive — hence fire-and-forget with a swallowed
+// catch. We do not await the returned promise at the call sites.
+
+import type { FastifyBaseLogger } from 'fastify';
+
+export type CoderCloseKind = 'chat' | 'session';
+
+function coderOrigin(): string {
+  // Same env + default as routes/sessions.ts' worktree-risk fetch.
+  return process.env.BOOCODER_URL ?? 'http://boocoder:3000';
+}
+
+/**
+ * Fire-and-forget POST to the BooCoder close hook for a chat or session.
+ *
+ * Resolves to `true` if the coder acknowledged (HTTP 2xx), `false` otherwise
+ * (non-2xx or network error). Callers SHOULD NOT await this — invoke it and
+ * move on. The returned promise never rejects: every failure path is caught,
+ * logged at debug, and folded into a `false` result so an unreachable or
+ * erroring coder can't surface to the user's delete/archive request.
+ */
+export async function notifyCoderClose(
+  kind: CoderCloseKind,
+  id: string,
+  log?: Pick<FastifyBaseLogger, 'debug'>,
+  fetcher: typeof fetch = fetch,
+): Promise<boolean> {
+  const segment = kind === 'chat' ? 'chats' : 'sessions';
+  const url = `${coderOrigin()}/api/${segment}/${id}/close`;
+  try {
+    const res = await fetcher(url, { method: 'POST' });
+    if (!res.ok) {
+      log?.debug(
+        { kind, id, status: res.status },
+        'coder close hook returned non-2xx (best-effort; reaper backstops)',
+      );
+      return false;
+    }
+    log?.debug({ kind, id }, 'coder close hook acknowledged');
+    return true;
+  } catch (err) {
+    log?.debug(
+      { kind, id, err: err instanceof Error ? err.message : String(err) },
+      'coder close hook unreachable (best-effort; reaper backstops)',
+    );
+    return false;
+  }
+}

apps/server/src/services/inference/budget.ts

@@ -18,9 +18,9 @@ import { READ_ONLY_TOOL_NAMES } from '../tools.js';
 // turns + deeper exploration without changing the safety floor materially —
 // the doom-loop guard (3 identical calls → abort) catches the actual failure
 // mode this cap was guarding against.
-export const BUDGET_READ_ONLY = 50;
+export const BUDGET_READ_ONLY = 100;
-export const BUDGET_NON_READ_ONLY = 10;
+export const BUDGET_NON_READ_ONLY = 100;
-export const BUDGET_NO_AGENT = 50;
+export const BUDGET_NO_AGENT = 100;
 
 const READ_ONLY_SET: ReadonlySet<string> = new Set(READ_ONLY_TOOL_NAMES);
 

apps/server/src/services/inference/llama-args-validator.ts

@@ -1,80 +1,139 @@
-// SPDX-License-Identifier: AGPL-3.0-only
+// Guards against agent-supplied llama-server CLI flags that would clash with
-// Copyright 2026-present the Unsloth AI Inc. team. All rights reserved.
+// values BooCode sets itself. Two concerns live here:
-// Ported from studio/backend/core/inference/llama_server_args.py.
+//
-// Original: https://github.com/unslothai/unsloth/blob/main/studio/backend/core/inference/llama_server_args.py
+//   1. A hard denylist of flags that BooCode owns outright (model selection,
+//      the listening socket, credentials, the bundled web UI). Passing any of
+//      these is a configuration error and is rejected loudly.
+//
+//   2. A "shadowing" set of flags that are legal to pass but, because of
+//      llama.cpp's last-wins argument parsing, would override a first-class
+//      BooCode setting. These are silently removed from the auto-generated
+//      argv so the agent's explicit choice takes precedence without leaving a
+//      duplicate flag behind.
+//
+// All flag spellings below are the public llama-server option names (short and
+// long aliases) documented in its --help output.
 
-// Each group is the full set of aliases (short + long) for one hard-denied
+// --- Hard denylist -------------------------------------------------------
-// flag, taken from the llama-server README. Flags NOT in this list pass
+
-// through and override auto-set values via llama.cpp's last-wins CLI parsing.
+// Authored as named buckets purely for readability; every alias is folded
-const DENYLIST_GROUPS: ReadonlyArray<ReadonlySet<string>> = [
+// into one flat lookup set at module load. Each inner array enumerates the
-  // Model identity
+// short + long spellings that select the same underlying option.
-  new Set(['-m', '--model']),
+const MODEL_SOURCE_FLAGS = [
-  new Set(['-mu', '--model-url']),
+  ['-m', '--model'],
-  new Set(['-dr', '--docker-repo']),
+  ['-mu', '--model-url'],
-  new Set(['-hf', '-hfr', '--hf-repo']),
+  ['-dr', '--docker-repo'],
-  new Set(['-hff', '--hf-file']),
+  ['-hf', '-hfr', '--hf-repo'],
-  new Set(['-hfv', '-hfrv', '--hf-repo-v']),
+  ['-hff', '--hf-file'],
-  new Set(['-hffv', '--hf-file-v']),
+  ['-hfv', '-hfrv', '--hf-repo-v'],
-  new Set(['-hft', '--hf-token']),
+  ['-hffv', '--hf-file-v'],
-  new Set(['-mm', '--mmproj']),
+  ['-hft', '--hf-token'],
-  new Set(['-mmu', '--mmproj-url']),
+  ['-mm', '--mmproj'],
-  // Networking
+  ['-mmu', '--mmproj-url'],
-  new Set(['--host']),
-  new Set(['--port']),
-  new Set(['--path']),
-  new Set(['--api-prefix']),
-  new Set(['--reuse-port']),
-  // Auth / TLS
-  new Set(['--api-key']),
-  new Set(['--api-key-file']),
-  new Set(['--ssl-key-file']),
-  new Set(['--ssl-cert-file']),
-  // Single-model server / UI
-  new Set(['--webui', '--no-webui']),
-  new Set(['--ui', '--no-ui']),
-  new Set(['--ui-config']),
-  new Set(['--ui-config-file']),
-  new Set(['--ui-mcp-proxy', '--no-ui-mcp-proxy']),
-  new Set(['--models-dir']),
-  new Set(['--models-preset']),
-  new Set(['--models-max']),
-  new Set(['--models-autoload', '--no-models-autoload']),
 ];
 
-const DENYLIST: ReadonlySet<string> = new Set(
+const LISTEN_FLAGS = [
-  DENYLIST_GROUPS.flatMap((g) => [...g]),
+  ['--host'],
+  ['--port'],
+  ['--path'],
+  ['--api-prefix'],
+  ['--reuse-port'],
+];
+
+const CREDENTIAL_FLAGS = [
+  ['--api-key'],
+  ['--api-key-file'],
+  ['--ssl-key-file'],
+  ['--ssl-cert-file'],
+];
+
+const WEBUI_FLAGS = [
+  ['--webui', '--no-webui'],
+  ['--ui', '--no-ui'],
+  ['--ui-config'],
+  ['--ui-config-file'],
+  ['--ui-mcp-proxy', '--no-ui-mcp-proxy'],
+  ['--models-dir'],
+  ['--models-preset'],
+  ['--models-max'],
+  ['--models-autoload', '--no-models-autoload'],
+];
+
+const MANAGED_FLAGS: ReadonlySet<string> = new Set(
+  [
+    ...MODEL_SOURCE_FLAGS,
+    ...LISTEN_FLAGS,
+    ...CREDENTIAL_FLAGS,
+    ...WEBUI_FLAGS,
+  ].flat(),
 );
 
-function flagName(token: string): string | null {
+// --- Token parsing -------------------------------------------------------
-  if (!token.startsWith('-') || token === '-' || token === '--') return null;
+
-  if (token.length >= 2 && (token[1]!.match(/\d/) || token[1] === '.')) return null;
+const DIGIT = /^[0-9]$/;
-  return token.split('=', 1)[0]!;
+
+/**
+ * Extract the flag name from a single argv token, or `null` when the token is
+ * not a flag.
+ *
+ * A token is treated as a flag only when it begins with `-` and the character
+ * after the leading dash is neither a digit nor a decimal point — that rule
+ * keeps negative numeric values such as `-1` or `-0.5` from being mistaken for
+ * options. A bare `-` or `--` is not a flag either. The returned name is the
+ * portion before any `=`, so `--ctx-size=4096` yields `--ctx-size`.
+ */
+function parseFlag(token: string): string | null {
+  if (!token.startsWith('-')) return null;
+  if (token === '-' || token === '--') return null;
+
+  const second = token[1]!;
+  if (DIGIT.test(second) || second === '.') return null;
+
+  const eq = token.indexOf('=');
+  return eq === -1 ? token : token.slice(0, eq);
 }
 
+// --- Public API ----------------------------------------------------------
+
+/**
+ * Validate a sequence of extra llama-server args, rejecting any that name a
+ * BooCode-managed flag. Returns the args materialised as a string[] when they
+ * all pass.
+ */
 export function validateExtraArgs(args?: Iterable<string>): string[] {
-  if (!args) return [];
+  const result: string[] = [];
-  const out: string[] = [];
+  if (!args) return result;
-  for (const raw of args) {
+
-    const token = String(raw);
+  for (const entry of args) {
-    const flag = flagName(token);
+    const token = String(entry);
-    if (flag !== null && DENYLIST.has(flag)) {
+    const flag = parseFlag(token);
+    if (flag !== null && MANAGED_FLAGS.has(flag)) {
       throw new Error(
         `llama-server flag '${flag}' is managed and cannot be passed as an extra arg`,
       );
     }
-    out.push(token);
+    result.push(token);
   }
-  return out;
+
+  return result;
 }
 
+/** True when `flag` is a BooCode-managed flag that callers may not override. */
 export function isManagedFlag(flag: string): boolean {
-  return DENYLIST.has(flag);
+  return MANAGED_FLAGS.has(flag);
 }
 
-// Shadowing flag groups: pass-through flags that shadow first-class settings.
+// --- Shadowing flags -----------------------------------------------------
-const CONTEXT_FLAGS = new Set(['-c', '--ctx-size']);
+
-const CACHE_FLAGS = new Set(['-ctk', '--cache-type-k', '-ctv', '--cache-type-v']);
+// Flags below are legal for an agent to pass, but each shadows a setting
-const SPEC_FLAGS = new Set([
+// BooCode applies itself. They are categorised so a caller can opt out of
+// stripping any one category.
+
+const SHADOW_CONTEXT = ['-c', '--ctx-size'];
+
+const SHADOW_CACHE = ['-ctk', '--cache-type-k', '-ctv', '--cache-type-v'];
+
+const SHADOW_SPEC = [
   '--spec-default',
   '--spec-type',
   '--spec-ngram-size-n',
@@ -88,17 +147,22 @@ const SPEC_FLAGS = new Set([
   '--spec-ngram-mod-n-match',
   '--spec-ngram-mod-n-min',
   '--spec-ngram-mod-n-max',
-]);
+];
-const TEMPLATE_FLAGS = new Set([
+
+const SHADOW_TEMPLATE = [
   '--chat-template',
   '--chat-template-file',
   '--chat-template-kwargs',
   '--jinja',
   '--no-jinja',
-]);
+];
 
-const BOOLEAN_SHADOWING_FLAGS = new Set([
+// Shadowing flags that take no value — a boolean switch — so the stripper must
-  '--spec-default', '--jinja', '--no-jinja',
+// not also drop the following token.
+const VALUELESS_SHADOW_FLAGS: ReadonlySet<string> = new Set([
+  '--spec-default',
+  '--jinja',
+  '--no-jinja',
 ]);
 
 export interface StripOptions {
@@ -108,35 +172,49 @@ export interface StripOptions {
   stripTemplate?: boolean;
 }
 
+/**
+ * Remove shadowing flags (and their values) from an argv sequence.
+ *
+ * Each category is stripped by default; pass the matching `strip*: false`
+ * option to retain that category. When a stripped flag carries its value as a
+ * separate following token (e.g. `-c 4096`), that token is removed too; the
+ * `--flag=value` and boolean-switch forms consume only the single token.
+ */
 export function stripShadowingFlags(
   args: Iterable<string>,
   opts?: StripOptions,
 ): string[] {
-  const shadowing = new Set<string>();
+  const targets = new Set<string>();
-  if (opts?.stripContext !== false) for (const f of CONTEXT_FLAGS) shadowing.add(f);
+  if (opts?.stripContext !== false) for (const f of SHADOW_CONTEXT) targets.add(f);
-  if (opts?.stripCache !== false) for (const f of CACHE_FLAGS) shadowing.add(f);
+  if (opts?.stripCache !== false) for (const f of SHADOW_CACHE) targets.add(f);
-  if (opts?.stripSpec !== false) for (const f of SPEC_FLAGS) shadowing.add(f);
+  if (opts?.stripSpec !== false) for (const f of SHADOW_SPEC) targets.add(f);
-  if (opts?.stripTemplate !== false) for (const f of TEMPLATE_FLAGS) shadowing.add(f);
+  if (opts?.stripTemplate !== false) for (const f of SHADOW_TEMPLATE) targets.add(f);
 
-  const tokens = [...args].map(String);
+  const tokens = Array.from(args, String);
-  const out: string[] = [];
+  const kept: string[] = [];
-  let i = 0;
+
-  const n = tokens.length;
+  for (let i = 0; i < tokens.length; i++) {
-  while (i < n) {
+    const token = tokens[i]!;
-    const tok = tokens[i]!;
+    const flag = parseFlag(token);
-    const flag = flagName(tok);
+
-    if (flag === null || !shadowing.has(flag)) {
+    // Not a targeted shadow flag — keep it verbatim.
-      out.push(tok);
+    if (flag === null || !targets.has(flag)) {
-      i++;
+      kept.push(token);
       continue;
     }
-    if (BOOLEAN_SHADOWING_FLAGS.has(flag) || tok.includes('=')) {
+
-      i++;
+    // Targeted: drop it. Decide whether the next token is its value and should
-    } else if (i + 1 < n && flagName(tokens[i + 1]!) === null) {
+    // be dropped along with it. Boolean switches and the inline `=value` form
-      i += 2;
+    // carry no separate value token.
-    } else {
+    const carriesInlineValue = token.includes('=');
-      i++;
+    const isBoolean = VALUELESS_SHADOW_FLAGS.has(flag);
+    const next = tokens[i + 1];
+    const nextIsValue = next !== undefined && parseFlag(next) === null;
+
+    if (!isBoolean && !carriesInlineValue && nextIsValue) {
+      i++; // also skip the value token
     }
   }
-  return out;
+
+  return kept;
 }

apps/server/src/services/inference/provider.ts

@@ -1,37 +1,84 @@
 import { createOpenAICompatible } from '@ai-sdk/openai-compatible';
 import type { LanguageModel } from 'ai';
 
-// TODO: When per-agent llama-server flag overrides are added, route them
-// through validateExtraArgs (./llama-args-validator.ts) first.
-
 // v1.13.1-A: AI SDK provider against llama-swap. baseURL is threaded from
 // config.LLAMA_SWAP_URL at call time (not module-load) so tests can stub the
 // upstream without touching env vars. No apiKey — llama-swap is unauth in our
 // Tailscale topology and exposing it over the public internet is gated by
 // Authelia at the Caddy layer, not by API keys.
+//
+// v2.4.1-sidecar: when the agent has llama_extra_args, route through
+// llama-sidecar instead. A fresh provider is created per call (not cached)
+// because the X-Agent-Flags header varies per agent. The llama-swap path
+// stays cached since it has no per-request headers.
 
-const cache = new Map<string, ReturnType<typeof createOpenAICompatible>>();
+const swapCache = new Map<string, ReturnType<typeof createOpenAICompatible>>();
 
-function getProvider(baseURL: string): ReturnType<typeof createOpenAICompatible> {
+function getSwapProvider(baseURL: string): ReturnType<typeof createOpenAICompatible> {
-  let provider = cache.get(baseURL);
+  let provider = swapCache.get(baseURL);
   if (!provider) {
     provider = createOpenAICompatible({
       name: 'llama-swap',
       baseURL: baseURL.endsWith('/v1') ? baseURL : `${baseURL}/v1`,
-      // v1.13.7: @ai-sdk/openai-compatible defaults includeUsage=false, which
-      // omits `stream_options.include_usage` from the request body. Without
-      // it, llama.cpp / llama-swap never emits the trailing usage block, so
-      // `result.usage` resolves with inputTokens=outputTokens=undefined and
-      // tokens_used / ctx_used land as NULL in every messages row. Setting
-      // true here re-enables the per-stream usage payload across all models
-      // served via the llama-swap provider.
       includeUsage: true,
     });
-    cache.set(baseURL, provider);
+    swapCache.set(baseURL, provider);
   }
   return provider;
 }
 
-export function upstreamModel(baseURL: string, modelId: string): LanguageModel {
+function sidecarProvider(
-  return getProvider(baseURL).chatModel(modelId);
+  baseURL: string,
+  flags: string[],
+): ReturnType<typeof createOpenAICompatible> {
+  return createOpenAICompatible({
+    name: 'llama-sidecar',
+    baseURL: baseURL.endsWith('/v1') ? baseURL : `${baseURL}/v1`,
+    includeUsage: true,
+    headers: {
+      'X-Agent-Flags': flags.join(' '),
+    },
+  });
+}
+
+export type InferenceRoute = 'swap' | 'sidecar';
+
+export interface RoutingInfo {
+  route: InferenceRoute;
+  flags: string[] | null;
+}
+
+interface AgentLike {
+  llama_extra_args: string[] | null;
+}
+
+interface ConfigLike {
+  LLAMA_SWAP_URL: string;
+  LLAMA_SIDECAR_URL?: string;
+}
+
+export function resolveRoute(agent: AgentLike | null): RoutingInfo {
+  const flags = agent?.llama_extra_args;
+  if (flags && flags.length > 0) {
+    return { route: 'sidecar', flags };
+  }
+  return { route: 'swap', flags: null };
+}
+
+export function upstreamModel(
+  config: ConfigLike,
+  modelId: string,
+  agent?: AgentLike | null,
+): LanguageModel {
+  const { route, flags } = resolveRoute(agent ?? null);
+  if (route === 'sidecar') {
+    const url = config.LLAMA_SIDECAR_URL;
+    if (!url) {
+      throw new Error(
+        `Agent has llama_extra_args but LLAMA_SIDECAR_URL is not set`,
+      );
+    }
+    return sidecarProvider(url, flags!).chatModel(modelId);
+  }
+  return getSwapProvider(config.LLAMA_SWAP_URL).chatModel(modelId);
 }

apps/server/src/services/inference/sentinel-summaries.ts

@@ -86,7 +86,7 @@ export async function runCapHitSummary(
       ctx,
       session.model,
       messages,
-      { tools: null, temperature: agent?.temperature, top_p: agent?.top_p ?? undefined, top_k: agent?.top_k ?? undefined, min_p: agent?.min_p ?? undefined, presence_penalty: agent?.presence_penalty ?? undefined },
+      { tools: null, temperature: agent?.temperature, top_p: agent?.top_p ?? undefined, top_k: agent?.top_k ?? undefined, min_p: agent?.min_p ?? undefined, presence_penalty: agent?.presence_penalty ?? undefined, top_n_sigma: agent?.top_n_sigma ?? undefined, dry_multiplier: agent?.dry_multiplier ?? undefined, dry_base: agent?.dry_base ?? undefined, dry_allowed_length: agent?.dry_allowed_length ?? undefined, dry_penalty_last_n: agent?.dry_penalty_last_n ?? undefined },
       (delta) => {
         accumulated += delta;
         ctx.publish(sessionId, {
@@ -346,7 +346,7 @@ export async function runDoomLoopSummary(
       ctx,
       session.model,
       messages,
-      { tools: null, temperature: agent?.temperature, top_p: agent?.top_p ?? undefined, top_k: agent?.top_k ?? undefined, min_p: agent?.min_p ?? undefined, presence_penalty: agent?.presence_penalty ?? undefined },
+      { tools: null, temperature: agent?.temperature, top_p: agent?.top_p ?? undefined, top_k: agent?.top_k ?? undefined, min_p: agent?.min_p ?? undefined, presence_penalty: agent?.presence_penalty ?? undefined, top_n_sigma: agent?.top_n_sigma ?? undefined, dry_multiplier: agent?.dry_multiplier ?? undefined, dry_base: agent?.dry_base ?? undefined, dry_allowed_length: agent?.dry_allowed_length ?? undefined, dry_penalty_last_n: agent?.dry_penalty_last_n ?? undefined },
       (delta) => {
         accumulated += delta;
         ctx.publish(sessionId, {
@@ -545,7 +545,7 @@ export async function runStepCapSummary(
       ctx,
       session.model,
       messages,
-      { tools: null, temperature: agent?.temperature, top_p: agent?.top_p ?? undefined, top_k: agent?.top_k ?? undefined, min_p: agent?.min_p ?? undefined, presence_penalty: agent?.presence_penalty ?? undefined },
+      { tools: null, temperature: agent?.temperature, top_p: agent?.top_p ?? undefined, top_k: agent?.top_k ?? undefined, min_p: agent?.min_p ?? undefined, presence_penalty: agent?.presence_penalty ?? undefined, top_n_sigma: agent?.top_n_sigma ?? undefined, dry_multiplier: agent?.dry_multiplier ?? undefined, dry_base: agent?.dry_base ?? undefined, dry_allowed_length: agent?.dry_allowed_length ?? undefined, dry_penalty_last_n: agent?.dry_penalty_last_n ?? undefined },
       (delta) => {
         accumulated += delta;
         ctx.publish(sessionId, {

apps/server/src/services/inference/stream-phase.ts

@@ -33,6 +33,39 @@ interface StreamOptions {
   top_k?: number | null;
   min_p?: number | null;
   presence_penalty?: number | null;
+  // v2.6 sampling-streamjson-tokens (#11): llama.cpp sampler extensions. These
+  // are NOT standard AI-SDK streamText options and are NOT serialized by the
+  // openai-compatible provider's standardized-settings path (topK is even
+  // explicitly dropped with an "unsupported feature: topK" warning). They reach
+  // llama-server only via providerOptions.openaiCompatible (see buildSamplerProviderOptions).
+  top_n_sigma?: number | null;
+  dry_multiplier?: number | null;
+  dry_base?: number | null;
+  dry_allowed_length?: number | null;
+  dry_penalty_last_n?: number | null;
+}
+
+// v2.6 #11: build the providerOptions.openaiCompatible extraBody object for the
+// llama.cpp sampler extensions. @ai-sdk/openai-compatible (2.0.47) merges every
+// non-reserved key under providerOptions.openaiCompatible straight into the
+// chat-completion request body (see its getArgs: the Object.fromEntries spread
+// filtered against openaiCompatibleLanguageModelChatOptions.shape). This is the
+// ONLY working passthrough for these params:
+//   - top_k / min_p were latently dropped before this: top_k was passed as the
+//     AI-SDK `topK` setting which the openai-compatible provider rejects as
+//     unsupported; min_p was never passed to streamText at all.
+//   - top_n_sigma + the dry_* family have no AI-SDK equivalent.
+// Keys use llama-server's snake_case body names so they land verbatim.
+function buildSamplerProviderOptions(opts: StreamOptions): Record<string, number> | undefined {
+  const body: Record<string, number> = {};
+  if (typeof opts.top_k === 'number') body.top_k = opts.top_k;
+  if (typeof opts.min_p === 'number') body.min_p = opts.min_p;
+  if (typeof opts.top_n_sigma === 'number') body.top_n_sigma = opts.top_n_sigma;
+  if (typeof opts.dry_multiplier === 'number') body.dry_multiplier = opts.dry_multiplier;
+  if (typeof opts.dry_base === 'number') body.dry_base = opts.dry_base;
+  if (typeof opts.dry_allowed_length === 'number') body.dry_allowed_length = opts.dry_allowed_length;
+  if (typeof opts.dry_penalty_last_n === 'number') body.dry_penalty_last_n = opts.dry_penalty_last_n;
+  return Object.keys(body).length > 0 ? body : undefined;
 }
 
 // v1.13.1-A: convert BooCode's OpenAI-shaped history into AI SDK
@@ -157,7 +190,8 @@ export async function streamCompletion(
   opts: StreamOptions,
   onDelta: (content: string) => void,
   onUsage: ((prompt: number | null, completion: number | null) => void) | undefined,
-  signal?: AbortSignal
+  signal?: AbortSignal,
+  agent?: Agent | null,
 ): Promise<StreamResult> {
   const aiMessages = toModelMessages(messages);
   const hasTools = opts.tools !== null && opts.tools.length > 0;
@@ -194,16 +228,24 @@ export async function streamCompletion(
     return toolCall;
   };
 
+  // v2.6 #11: llama.cpp sampler extensions (top_k, min_p, top_n_sigma, dry_*)
+  // ride providerOptions.openaiCompatible — they are NOT standardized streamText
+  // settings. NB: top_k used to be passed below as the AI-SDK `topK` setting;
+  // the openai-compatible provider dropped it with an "unsupported feature: topK"
+  // warning and min_p was never wired at all, so both were dead on the wire
+  // before this. They now go through the same extraBody path as the new params.
+  const samplerBody = buildSamplerProviderOptions(opts);
+
   const result = streamText({
-    model: upstreamModel(ctx.config.LLAMA_SWAP_URL, model),
+    model: upstreamModel(ctx.config, model, agent ?? null),
     messages: aiMessages,
     ...(aiTools
       ? { tools: aiTools, toolChoice: 'auto' as const, experimental_repairToolCall: repairToolCall }
       : {}),
     ...(typeof opts.temperature === 'number' ? { temperature: opts.temperature } : {}),
     ...(typeof opts.top_p === 'number' ? { topP: opts.top_p } : {}),
-    ...(typeof opts.top_k === 'number' ? { topK: opts.top_k } : {}),
     ...(typeof opts.presence_penalty === 'number' ? { presencePenalty: opts.presence_penalty } : {}),
+    ...(samplerBody ? { providerOptions: { openaiCompatible: samplerBody } } : {}),
     abortSignal: signal,
   });
 
@@ -397,6 +439,12 @@ export async function executeStreamPhase(
   const effectiveTopK = agent?.top_k ?? undefined;
   const effectiveMinP = agent?.min_p ?? undefined;
   const effectivePresencePenalty = agent?.presence_penalty ?? undefined;
+  // v2.6 #11: llama.cpp sampler extensions, threaded the same way as top_k/min_p.
+  const effectiveTopNSigma = agent?.top_n_sigma ?? undefined;
+  const effectiveDryMultiplier = agent?.dry_multiplier ?? undefined;
+  const effectiveDryBase = agent?.dry_base ?? undefined;
+  const effectiveDryAllowedLength = agent?.dry_allowed_length ?? undefined;
+  const effectiveDryPenaltyLastN = agent?.dry_penalty_last_n ?? undefined;
 
   // v1.12.2: ctx_max lookup is cached after the first hit per model, so this
   // is a Map probe in steady state. We capture nCtx once at the top of the
@@ -434,7 +482,19 @@ export async function executeStreamPhase(
       ctx,
       session.model,
       messages,
-      { tools: effectiveTools, temperature: effectiveTemperature, top_p: effectiveTopP, top_k: effectiveTopK, min_p: effectiveMinP, presence_penalty: effectivePresencePenalty },
+      {
+        tools: effectiveTools,
+        temperature: effectiveTemperature,
+        top_p: effectiveTopP,
+        top_k: effectiveTopK,
+        min_p: effectiveMinP,
+        presence_penalty: effectivePresencePenalty,
+        top_n_sigma: effectiveTopNSigma,
+        dry_multiplier: effectiveDryMultiplier,
+        dry_base: effectiveDryBase,
+        dry_allowed_length: effectiveDryAllowedLength,
+        dry_penalty_last_n: effectiveDryPenaltyLastN,
+      },
       (delta) => {
         state.accumulated += delta;
         ctx.publish(sessionId, {
@@ -458,7 +518,8 @@ export async function executeStreamPhase(
           }, USAGE_THROTTLE_MS - elapsed);
         }
       },
-      signal
+      signal,
+      agent,
     );
   } finally {
     if (pendingFlushTimer) {