feat: normalized external-agent status (#10 scoped) (v2.7.6)

Scoped half of boocode_code_review_v2 §1 #10 — publish the agent status
BooCoder already observes (the config-injection notify-hook is the documented
follow-on, clean-room from superset ELv2).

- agent_status_updated WS frame (working|blocked|idle|error), server+web parity.
- Published from the dispatcher's turn boundaries (warm-acp/opencode/sdk/pty:
  working at start, idle/error at end) + the permission flow (blocked/working).
  Best-effort, never breaks a turn.
- Clean-room normalizeAgentEvent helper (superset's vendor-event -> Start/blocked
  /Stop collapse, event names as facts) + 25 tests — reused by the follow-on.
- AgentComposerBar status dot (distinct from the WS-liveness dot), tracked per
  (chat,agent) by a useAgentStatus map in CoderPane.

Built by 2 parallel agents vs a pinned frame contract. Server 545 + coder 294
tests passing (25 new); web tsc + builds clean; ws-frames parity green. Clears
the actionable review backlog (#1/#3/#4/#6-#12). Builds on v2.7.5.

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

CHANGELOG.md

@@ -2,6 +2,18 @@
 
 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.
 
+## v2.7.6-agent-status-normalize — 2026-06-01
+
+The scoped half of `boocode_code_review_v2.md` §1 #10 — normalized external-agent status, surfaced from BooCoder's own dispatch observation (the heavier config-injection notify-hook, clean-room from superset's ELv2 `agent-setup`, is documented as the follow-on). The review's premise ("PTY agents have no status") had partly aged out — warm-ACP/opencode/SDK already carry working/done — so the real gap was that BooCoder never *published* a normalized per-`(chat,agent)` status (blocked-on-permission was invisible; crash/idle weren't pushed). Adds an `agent_status_updated` WS frame (`working|blocked|idle|error`, server+web parity) published from the dispatcher's turn boundaries across all four external paths (warm-acp/opencode/sdk/pty — `working` at start, `idle`/`error` at end) and the permission flow (`blocked` on request, `working` on resolve), best-effort so it never breaks a turn. A clean-room `normalizeAgentEvent` helper (superset's ~30-vendor-event → Start/blocked/Stop collapse, reimplemented with the event names as facts) ships now with 25 tests so the deferred notify-hook injection reuses it verbatim. The `AgentComposerBar` gains a normalized status dot (working=spinner, blocked=amber, idle=gray, error=red) distinct from the WS-liveness dot, fed by a `useAgentStatus` map `CoderPane` tracks per `(chat,agent)`. Built by two parallel agents (data plane + view plane) against a pinned frame contract; server 545 + coder 294 tests passing (25 new), web tsc + builds clean, ws-frames parity green. Clears the actionable review backlog (#1/#3/#4/#6–#12). Builds on `v2.7.5-claude-sdk-sessionstore`; openspec `agent-status-normalize`.
+
+## v2.7.5-claude-sdk-sessionstore — 2026-06-01
+
+Lands the Claude Agent SDK direction (`boocode_code_review_v2.md` §1 #9, §6.2 "lean SDK") behind a flag. Adds `@anthropic-ai/claude-agent-sdk@0.3.159` (Commercial Terms — runtime dep, code reference-only) and builds a warm, resumable claude backend to supersede one-shot PTY dispatch — env-gated (`CLAUDE_SDK_BACKEND`, default off) so production claude stays on the unchanged PTY path until a host smoke. **Clean-room `PostgresSessionStore`** implements the SDK's real `SessionStore` type (`append`/`load`/`listSessions`/`delete`/`listSubkeys`) over a new `claude_session_entries` table — typechecked against the installed SDK type, 8 DB-integration tests. **`ClaudeSdkBackend`** (`implements AgentBackend`, mirroring warm-acp/opencode-server) drives one persistent `query()` per `(chat,'claude')` in streaming-input mode via a pushable async-iterable pump, with `sessionStore` + `resume` for cross-turn/cross-restart continuity, a pure `mapSdkMessage`→`AgentEvent` mapper, `session_id` captured from the `init` message, and `result.usage`/`total_cost_usd` accumulated onto `agent_sessions` (backend CHECK gains `'claude_sdk'`). Built against the REAL SDK 0.3.159 types after installing it — surfacing shapes a blind build would have missed (`SDKPartialAssistantMessage` is `type:'stream_event'` needing `includePartialMessages`; `SDKUserMessage.message` is `MessageParam`; the `SDKResultMessage` error arm). Also fixes a latent test-infra deadlock — three DB-integration suites applying the full schema in parallel under `DATABASE_URL` deadlocked, now serialized via `fileParallelism:false`. ~32 new tests (8 store + 10 mapper + 8 pushable + 6 routing); coder suite 269 passing default / 290 with DB; tsc clean against the SDK types; builds clean. **The live streaming pump + resume + an actual claude turn need a host smoke (`CLAUDE_SDK_BACKEND=1` + claude binary + ANTHROPIC auth) — cannot run from the dev container.** The zod peer-dep wants `^4` (workspace `3.25`) — watch at runtime. Builds on `v2.7.4-mistake-tracker-ledger`; openspec `claude-sdk-sessionstore`.
+
+## v2.7.4-mistake-tracker-ledger — 2026-06-01
+
+Two native-inference hardening features from `boocode_code_review_v2.md` §1 #12 (cline, algorithm-reimplemented). **MistakeTracker:** complements the doom-loop guard (identical repeats) and cap-hit (budget) by catching a run of consecutive tool *failures*. A new pure `mistake-tracker.ts` tracks heterogeneous failure kinds (`zod_reject`/`tool_not_found`/`exec_error`/`api_error`/`permission_denied`, surfaced per tool from `tool-phase.ts`); after 3 consecutive failures the `turn.ts` loop does a **soft nudge** — injects model-facing recovery guidance into the next step + drops a `mistake_recovery` UI sentinel + resets — then **escalates** to stopping the turn (cap-hit-style, with a Continue affordance) if it re-trips without an intervening success, so heterogeneous failures can't burn the whole step budget. **File-provenance ledger:** `compaction.ts` now derives a deterministic, sorted `## Files Read` list from the head messages' read-tool calls (`view_file`/`grep`/`find_files`/`list_dir`) and injects it into the rolling-summary prompt so file provenance survives compaction (no new table; prompt-driven merge, read-only since BooChat has no write tools). The `mistake_recovery` sentinel adds an arm to `MessageMetadata` in both server + web type copies plus a `MessageBubble` render branch. Built by two parallel agents (backend + frontend sentinel) over disjoint apps; server 545 tests passing (23 new: 12 mistake-tracker + 11 compaction), build + web tsc clean. Native-inference only (external agents run their own loops). Builds on `v2.7.3-sampling-streamjson-tokens`; openspec `mistake-tracker-file-ledger`.
+
 ## v2.7.3-sampling-streamjson-tokens — 2026-06-01
 
 Three small BooCode wins from `boocode_code_review_v2.md` §1 #11/#7/#8. **Sampling knobs:** per-agent `top_n_sigma` + the `dry_*` repetition family (`dry_multiplier`/`dry_base`/`dry_allowed_length`/`dry_penalty_last_n`) are now first-class Agent frontmatter fields, parsed in `agents.ts` and threaded into the llama-swap chat-completion body via `providerOptions.openaiCompatible` (the `@ai-sdk/openai-compatible` extra-body channel). This surfaced and fixed a **latent bug**: `top_k` (rejected by the AI-SDK provider as unsupported) and `min_p` (never passed to `streamText` at all) had been dead on the wire — no agent's `top_k`/`min_p` ever affected sampling; both now route through the same channel, so agents that set them will start using them. `--reasoning-budget` is documented in `data/AGENTS.md` (already works via `llama_extra_args`, permitted by the deny-list validator). **Live PTY stream-json:** qwen/claude PTY dispatch sliced stdout opaque; a new `stream-json-parser.ts` line-buffers the Claude-Code-compatible NDJSON and emits text/reasoning/tool frames live as they arrive (mirroring the ACP/opencode paths) + persists the structured parts, with a clean fallback to the old opaque slice when output isn't NDJSON (claude now runs `--output-format stream-json --verbose`). **Token UI:** the per-`(chat,agent)` `agent_sessions.input_tokens`/`output_tokens`/`cost` columns (accumulated since `v2.6.8` but dropped by the read route + wire type) now flow through and render condensed beside the AgentComposerBar session chip. Built by three parallel agents over disjoint subsystems; server 523 + coder 245 tests passing (incl. 11 new stream-json-parser + new agent-parse tests), all builds + web tsc clean. Builds on `v2.7.2-checkpoint-idor`; openspec `sampling-streamjson-tokens`. The qwen-vs-claude `usage` field names in #7 are best-guess pending a live smoke.

apps/coder/package.json

@@ -14,11 +14,12 @@
   },
   "dependencies": {
     "@agentclientprotocol/sdk": "^0.22.1",
+    "@anthropic-ai/claude-agent-sdk": "^0.3.159",
     "@boocode/server": "workspace:*",
     "@fastify/static": "^7.0.4",
-    "@opencode-ai/sdk": "~1.15.0",
     "@fastify/websocket": "^10.0.1",
     "@modelcontextprotocol/sdk": "^1.29.0",
+    "@opencode-ai/sdk": "~1.15.0",
     "fastify": "^4.28.1",
     "postgres": "^3.4.4",
     "ws": "^8.18.0",

apps/coder/src/index.ts

@@ -42,6 +42,7 @@ import { createOrphanWorktreeReaper } from './services/orphan-worktree-reaper.js
 import { probeAgents } from './services/agent-probe.js';
 import { getProviderSnapshot, persistProbedModels } from './services/provider-snapshot.js';
 import { setPermissionHooks } from './services/permission-waiter.js';
+import { publishAgentStatus } from './services/agent-status-publish.js';
 import { homedir } from 'node:os';
 
 async function main() {
@@ -82,6 +83,21 @@ async function main() {
   // Broker: in-memory pub/sub for session + user channel streaming.
   const broker = createBroker(app.log);
 
+  // agent-status-normalize (#10): the permission hooks carry only taskId +
+  // sessionId, but the tasks row holds the (chat_id, agent) pair the status frame
+  // is keyed on. Resolve it best-effort so a blocked/working status accompanies
+  // every permission_requested/permission_resolved. Returns null when the task
+  // lacks a chat_id or agent (sessionless creators) — we simply skip the status.
+  const resolveChatAgent = async (
+    taskId: string,
+  ): Promise<{ chatId: string; agent: string } | null> => {
+    const [row] = await sql<{ chat_id: string | null; agent: string | null }[]>`
+      SELECT chat_id, agent FROM tasks WHERE id = ${taskId}
+    `;
+    if (!row?.chat_id || !row.agent) return null;
+    return { chatId: row.chat_id, agent: row.agent };
+  };
+
   setPermissionHooks({
     onPrompt: async (prompt) => {
       await sql`
@@ -96,6 +112,18 @@ async function main() {
         ...(prompt.input ? { input: prompt.input } : {}),
         options: prompt.options.map((o) => ({ option_id: o.optionId, label: o.label })),
       } as WsFrame);
+      // #10: agent is blocked on a human decision.
+      const ca = await resolveChatAgent(prompt.taskId).catch(() => null);
+      if (ca) {
+        publishAgentStatus(
+          broker.publishFrame,
+          prompt.sessionId,
+          ca.chatId,
+          ca.agent,
+          'blocked',
+          'permission_request',
+        );
+      }
     },
     onResolved: async (taskId, sessionId) => {
       await sql`
@@ -106,6 +134,18 @@ async function main() {
         task_id: taskId,
         session_id: sessionId,
       } as WsFrame);
+      // #10: human responded — agent resumes work.
+      const ca = await resolveChatAgent(taskId).catch(() => null);
+      if (ca) {
+        publishAgentStatus(
+          broker.publishFrame,
+          sessionId,
+          ca.chatId,
+          ca.agent,
+          'working',
+          'permission_resolved',
+        );
+      }
     },
   });
 

apps/coder/src/schema.sql

@@ -261,6 +261,34 @@ CREATE TABLE IF NOT EXISTS checkpoints (
 );
 CREATE INDEX IF NOT EXISTS checkpoints_chat_created_idx ON checkpoints(chat_id, created_at);
 
+-- claude-sdk-sessionstore #9 (Part 1): append-only mirror of Claude Agent SDK
+-- session transcripts. The SDK's SessionStore adapter writes one JSONL line per
+-- entry; PostgresSessionStore (services/backends/claude-session-store.ts) inserts
+-- one row per entry and replays them ORDER BY id on resume. The store is generic
+-- per the SDK's SessionKey (project_key, session_id, subpath) — chat↔session
+-- ownership lives in agent_sessions, not here. subpath '' is the main transcript
+-- (the SDK's undefined subpath maps to '' in the column).
+CREATE TABLE IF NOT EXISTS claude_session_entries (
+  id          BIGSERIAL PRIMARY KEY,
+  project_key TEXT NOT NULL,
+  session_id  TEXT NOT NULL,
+  subpath     TEXT NOT NULL DEFAULT '',   -- '' = main transcript (SDK's undefined subpath maps here)
+  entry       JSONB NOT NULL,
+  created_at  TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
+);
+CREATE INDEX IF NOT EXISTS claude_session_entries_key_idx ON claude_session_entries (project_key, session_id, subpath, id);
+
+-- claude-sdk-sessionstore #9 (Part 2): the warm Claude-SDK backend persists its
+-- agent_sessions rows with backend='claude_sdk'. Widen the named CHECK to accept
+-- it. Idempotent: DROP the named constraint (the inline CREATE TABLE check above
+-- carries this explicit name, so DROP IF EXISTS targets it) + re-ADD the widened
+-- list. Re-runs/fresh deploys land on the same final constraint (the table-level
+-- CREATE already includes only the old two values on a fresh DB; this block then
+-- replaces it with the three-value list).
+ALTER TABLE agent_sessions DROP CONSTRAINT IF EXISTS agent_sessions_backend_chk;
+ALTER TABLE agent_sessions ADD CONSTRAINT agent_sessions_backend_chk
+  CHECK (backend IN ('opencode_server', 'acp_warm', 'claude_sdk'));
+
 -- LISTEN/NOTIFY fast path: every tasks INSERT (from any call site — routes,
 -- new_task tool, arena, MCP server) fires pg_notify('tasks_new') in the same
 -- transaction, so the dispatcher reacts immediately instead of waiting for the

apps/coder/src/services/__tests__/normalize-agent-status.test.ts

@@ -0,0 +1,83 @@
+import { describe, it, expect } from 'vitest';
+import { normalizeAgentEvent } from '../normalize-agent-status.js';
+
+describe('normalizeAgentEvent', () => {
+  describe('working bucket', () => {
+    const cases = [
+      'SessionStart',
+      'UserPromptSubmit',
+      'UserPromptSubmitted',
+      'PostToolUse',
+      'PostToolUseFailure',
+      'BeforeAgent',
+      'AfterTool',
+      'task_started',
+    ];
+    for (const name of cases) {
+      it(`maps ${name} → working`, () => {
+        expect(normalizeAgentEvent(name)).toBe('working');
+      });
+    }
+  });
+
+  describe('blocked bucket', () => {
+    const cases = [
+      'PreToolUse',
+      'Notification',
+      'PermissionRequest',
+      'exec_approval_request',
+      'apply_patch_approval_request',
+      'request_user_input',
+    ];
+    for (const name of cases) {
+      it(`maps ${name} → blocked`, () => {
+        expect(normalizeAgentEvent(name)).toBe('blocked');
+      });
+    }
+  });
+
+  describe('done bucket', () => {
+    const cases = [
+      'Stop',
+      'AfterAgent',
+      'SessionEnd',
+      'task_complete',
+      'agent-turn-complete',
+    ];
+    for (const name of cases) {
+      it(`maps ${name} → done`, () => {
+        expect(normalizeAgentEvent(name)).toBe('done');
+      });
+    }
+  });
+
+  describe('unknown / nullish → null', () => {
+    it('returns null for an unrecognized event', () => {
+      expect(normalizeAgentEvent('SomeRandomEvent')).toBeNull();
+    });
+    it('returns null for empty string', () => {
+      expect(normalizeAgentEvent('')).toBeNull();
+    });
+    it('returns null for undefined', () => {
+      expect(normalizeAgentEvent(undefined)).toBeNull();
+    });
+  });
+
+  describe('case- and separator-insensitive matching', () => {
+    it('matches snake_case spelling of a PascalCase event', () => {
+      expect(normalizeAgentEvent('session_start')).toBe('working');
+      expect(normalizeAgentEvent('post_tool_use')).toBe('working');
+      expect(normalizeAgentEvent('pre_tool_use')).toBe('blocked');
+    });
+    it('matches camelCase spelling', () => {
+      expect(normalizeAgentEvent('userPromptSubmitted')).toBe('working');
+      expect(normalizeAgentEvent('postToolUse')).toBe('working');
+      expect(normalizeAgentEvent('preToolUse')).toBe('blocked');
+      expect(normalizeAgentEvent('sessionEnd')).toBe('done');
+    });
+    it('matches arbitrary case', () => {
+      expect(normalizeAgentEvent('STOP')).toBe('done');
+      expect(normalizeAgentEvent('notification')).toBe('blocked');
+    });
+  });
+});

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

@@ -13,7 +13,7 @@ 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';
+export type AgentBackendKind = 'opencode_server' | 'acp_warm' | 'claude_sdk';
 
 /**
  * Normalized, transport-agnostic events a backend emits during a turn (§2).

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

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

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

@@ -0,0 +1,181 @@
+import { describe, it, expect } from 'vitest';
+import type { SDKMessage } from '@anthropic-ai/claude-agent-sdk';
+import { mapSdkMessage, createClaudeSdkMapState } from '../claude-sdk-map.js';
+import type { AgentEvent } from '../../agent-backend.js';
+
+/**
+ * Pure mapper for Claude-SDK messages → AgentEvents (claude-sdk-sessionstore #9 Part 2).
+ * Verifies the partial-stream → live-delta mapping, tool assembly across blocks, and
+ * the final-assistant dedup, with no live `claude` binary involved.
+ *
+ * Messages are cast through `unknown` to `SDKMessage`: the real SDK shapes carry many
+ * fields (uuid, parent_tool_use_id, …) irrelevant to the mapper, which reads only the
+ * `type`/`event`/`message.content` it discriminates on. The cast keeps the fixtures
+ * minimal while the production code path sees the full real types (the backend's
+ * typecheck against the real SDK is the type-safety proof).
+ */
+function msg(m: unknown): SDKMessage {
+  return m as SDKMessage;
+}
+
+/** A partial-stream message wrapping one BetaRawMessageStreamEvent. */
+function streamEvent(event: unknown): SDKMessage {
+  return msg({ type: 'stream_event', event, parent_tool_use_id: null, uuid: 'u', session_id: 's' });
+}
+
+describe('mapSdkMessage — partial stream deltas', () => {
+  it('maps a text_delta to a text event', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(
+      streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text: 'Hello' } }),
+      state,
+    );
+    expect(out).toEqual<AgentEvent[]>([{ type: 'text', text: 'Hello' }]);
+  });
+
+  it('maps a thinking_delta to a reasoning event', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(
+      streamEvent({
+        type: 'content_block_delta',
+        index: 0,
+        delta: { type: 'thinking_delta', thinking: 'pondering', estimated_tokens: null },
+      }),
+      state,
+    );
+    expect(out).toEqual<AgentEvent[]>([{ type: 'reasoning', text: 'pondering' }]);
+  });
+
+  it('drops empty text/thinking deltas', () => {
+    const state = createClaudeSdkMapState();
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text: '' } }), state),
+    ).toEqual([]);
+    expect(
+      mapSdkMessage(
+        streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'thinking_delta', thinking: '', estimated_tokens: null } }),
+        state,
+      ),
+    ).toEqual([]);
+  });
+
+  it('ignores message framing + signature/citation deltas', () => {
+    const state = createClaudeSdkMapState();
+    expect(mapSdkMessage(streamEvent({ type: 'message_start', message: {} }), state)).toEqual([]);
+    expect(mapSdkMessage(streamEvent({ type: 'message_stop' }), state)).toEqual([]);
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'signature_delta', signature: 'x' } }), state),
+    ).toEqual([]);
+  });
+});
+
+describe('mapSdkMessage — tool assembly across blocks', () => {
+  it('opens a tool_call on content_block_start, buffers input_json_delta, emits tool_update with parsed input on stop', () => {
+    const state = createClaudeSdkMapState();
+
+    const started = mapSdkMessage(
+      streamEvent({
+        type: 'content_block_start',
+        index: 1,
+        content_block: { type: 'tool_use', id: 'tool-1', name: 'view_file', input: {} },
+      }),
+      state,
+    );
+    expect(started).toEqual<AgentEvent[]>([
+      { type: 'tool_call', toolCall: { toolCallId: 'tool-1', title: 'view_file', kind: null, status: 'in_progress', rawInput: {}, rawOutput: undefined } },
+    ]);
+
+    // args stream in fragments under the same block index
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 1, delta: { type: 'input_json_delta', partial_json: '{"path":' } }), state),
+    ).toEqual([]);
+    expect(
+      mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 1, delta: { type: 'input_json_delta', partial_json: '"a.ts"}' } }), state),
+    ).toEqual([]);
+
+    const stopped = mapSdkMessage(streamEvent({ type: 'content_block_stop', index: 1 }), state);
+    expect(stopped).toHaveLength(1);
+    const ev = stopped[0]!;
+    expect(ev.type).toBe('tool_update');
+    if (ev.type === 'tool_update') {
+      expect(ev.toolCall.toolCallId).toBe('tool-1');
+      expect(ev.toolCall.title).toBe('view_file');
+      expect(ev.toolCall.rawInput).toEqual({ path: 'a.ts' });
+    }
+  });
+
+  it('content_block_stop for a non-tool block (no tracked index) emits nothing', () => {
+    const state = createClaudeSdkMapState();
+    // text block was streamed at index 0 but never tracked as a tool
+    mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text: 'hi' } }), state);
+    expect(mapSdkMessage(streamEvent({ type: 'content_block_stop', index: 0 }), state)).toEqual([]);
+  });
+
+  it('falls back to the prior input when the buffered tool JSON is invalid', () => {
+    const state = createClaudeSdkMapState();
+    mapSdkMessage(
+      streamEvent({ type: 'content_block_start', index: 2, content_block: { type: 'tool_use', id: 't2', name: 'grep', input: { q: 'seed' } } }),
+      state,
+    );
+    mapSdkMessage(streamEvent({ type: 'content_block_delta', index: 2, delta: { type: 'input_json_delta', partial_json: '{not json' } }), state);
+    const stopped = mapSdkMessage(streamEvent({ type: 'content_block_stop', index: 2 }), state);
+    const ev = stopped[0]!;
+    if (ev.type === 'tool_update') {
+      expect(ev.toolCall.rawInput).toEqual({ q: 'seed' });
+    } else {
+      throw new Error('expected tool_update');
+    }
+  });
+});
+
+describe('mapSdkMessage — final assistant message', () => {
+  function assistant(content: unknown[]): SDKMessage {
+    return msg({ type: 'assistant', message: { content }, parent_tool_use_id: null, uuid: 'u', session_id: 's' });
+  }
+
+  it('dedups text/thinking (already streamed) and emits a completed tool_update per tool_use block', () => {
+    const state = createClaudeSdkMapState();
+    const out = mapSdkMessage(
+      assistant([
+        { type: 'text', text: 'final answer', citations: null },
+        { type: 'thinking', thinking: 'reasoned', signature: 'sig' },
+        { type: 'tool_use', id: 'tool-9', name: 'find_files', input: { glob: '**/*.ts' } },
+      ]),
+      state,
+    );
+    expect(out).toEqual<AgentEvent[]>([
+      {
+        type: 'tool_update',
+        toolCall: { toolCallId: 'tool-9', title: 'find_files', kind: null, status: 'completed', rawInput: { glob: '**/*.ts' }, rawOutput: undefined },
+      },
+    ]);
+  });
+
+  it('preserves a title from a prior partial tool_call snapshot', () => {
+    const state = createClaudeSdkMapState();
+    mapSdkMessage(
+      streamEvent({ type: 'content_block_start', index: 0, content_block: { type: 'tool_use', id: 'tool-x', name: 'view_file', input: {} } }),
+      state,
+    );
+    const out = mapSdkMessage(assistant([{ type: 'tool_use', id: 'tool-x', name: 'view_file', input: { path: 'z' } }]), state);
+    const ev = out[0]!;
+    if (ev.type === 'tool_update') {
+      expect(ev.toolCall.status).toBe('completed');
+      expect(ev.toolCall.title).toBe('view_file');
+      expect(ev.toolCall.rawInput).toEqual({ path: 'z' });
+    } else {
+      throw new Error('expected tool_update');
+    }
+  });
+});
+
+describe('mapSdkMessage — non-content messages', () => {
+  it('returns [] for system/init, status, result, and other variants', () => {
+    const state = createClaudeSdkMapState();
+    expect(mapSdkMessage(msg({ type: 'system', subtype: 'init', session_id: 's', uuid: 'u' }), state)).toEqual([]);
+    expect(mapSdkMessage(msg({ type: 'system', subtype: 'status', status: null, session_id: 's', uuid: 'u' }), state)).toEqual([]);
+    expect(
+      mapSdkMessage(msg({ type: 'result', subtype: 'success', result: 'done', session_id: 's', uuid: 'u' }), state),
+    ).toEqual([]);
+  });
+});

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

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

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

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

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

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

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

@@ -0,0 +1,192 @@
+/**
+ * claude-sdk-sessionstore #9 (Part 2) — PURE Claude-SDK message → AgentEvent mapper.
+ *
+ * `ClaudeSdkBackend` drives one `query()` per (chat, agent) session and feeds each
+ * `SDKMessage` it yields through this function, forwarding the returned
+ * `AgentEvent[]` to the dispatcher's `onEvent` (which maps them to WS frames +
+ * persists). Kept PURE (one message + a caller-owned accumulator → events) so it's
+ * unit-testable without a live `claude` binary — the whole point of Part 2's
+ * typecheck-and-unit-test gate (the live pump needs a host smoke).
+ *
+ * SDK shapes (verified against @anthropic-ai/claude-agent-sdk@0.3.159 sdk.d.ts +
+ * @anthropic-ai/sdk beta messages d.ts):
+ *   - `SDKPartialAssistantMessage` (`type:'stream_event'`) carries a
+ *     `BetaRawMessageStreamEvent` — the LIVE delta stream (only emitted when
+ *     `options.includePartialMessages` is set, which the backend sets). We map:
+ *       · content_block_delta + text_delta      → { text }
+ *       · content_block_delta + thinking_delta   → { reasoning }
+ *       · content_block_start  + tool_use block  → { tool_call } (in_progress)
+ *       · content_block_delta + input_json_delta → buffered into the tool's args
+ *         (no event; the assembled input rides the terminal tool_update)
+ *   - `SDKAssistantMessage` (`type:'assistant'`) carries the FINAL `message.content`
+ *     blocks. Text/thinking there are post-hoc repeats of what the partials already
+ *     streamed, so we DROP them (dedup) and only emit a terminal `tool_update`
+ *     (status completed) per `tool_use` block, with its now-complete `input`.
+ *   - All other `SDKMessage` variants (system/init, status, result, hooks, task
+ *     notifications, …) carry no renderable turn content → return [].
+ *
+ * Tool assembly spans messages: a tool_use block opens in a partial
+ * `content_block_start`, its args stream as `input_json_delta` frames keyed by the
+ * block `index`, and the final assistant message restates the complete block. The
+ * caller owns a `ClaudeSdkMapState` (snapshot map + per-index tool tracking) that
+ * threads this across calls, mirroring the `Map<string, AcpToolSnapshot>` the other
+ * backends pass into `mapSessionUpdate`. The result frames carry the SAME
+ * `AcpToolSnapshot` shape, so `persistExternalAgentTurn` / `snapshotToWireToolCall`
+ * are reused unchanged.
+ */
+import type { SDKMessage } from '@anthropic-ai/claude-agent-sdk';
+import type { AgentEvent } from '../agent-backend.js';
+import type { AcpToolSnapshot } from '../acp-tool-snapshot.js';
+
+/**
+ * The underlying `@anthropic-ai/sdk` Beta message types (`BetaRawMessageStreamEvent`,
+ * `BetaContentBlock`) are a TRANSITIVE dep of `@anthropic-ai/claude-agent-sdk` — not
+ * a direct dependency of apps/coder — so a `@anthropic-ai/sdk/...` import does NOT
+ * resolve here under pnpm's strict node_modules. We instead DERIVE both shapes from
+ * the SDK's own exported message types, which is also more correct (it tracks the
+ * exact `event` / `content` shapes the SDK yields, not a hand-picked import path).
+ */
+type StreamEvent = Extract<SDKMessage, { type: 'stream_event' }>['event'];
+type AssistantContent = Extract<SDKMessage, { type: 'assistant' }>['message']['content'];
+type ContentBlock = AssistantContent extends readonly (infer B)[] ? B : never;
+
+/**
+ * Caller-owned accumulator threaded across `mapSdkMessage` calls within ONE turn.
+ * The backend creates a fresh one per turn and clears it at turn end.
+ */
+export interface ClaudeSdkMapState {
+  /** Stable tool-call snapshots by tool_use id, merged across start/delta/stop. */
+  snapshots: Map<string, AcpToolSnapshot>;
+  /**
+   * Partial-stream block index → in-flight tool assembly. Anthropic's stream keys
+   * blocks by a numeric `index`; tool_use args arrive as `input_json_delta`s under
+   * that index with no id, so we map index→id to route them and buffer the raw
+   * JSON fragments until the block closes (or the final assistant message lands).
+   */
+  toolByIndex: Map<number, { id: string; name: string; jsonBuf: string }>;
+}
+
+/** Construct a fresh per-turn accumulator. */
+export function createClaudeSdkMapState(): ClaudeSdkMapState {
+  return { snapshots: new Map(), toolByIndex: new Map() };
+}
+
+/**
+ * Map one `SDKMessage` → zero or more `AgentEvent`s, mutating `state` for
+ * cross-message tool assembly + dedup. Pure w.r.t. its inputs otherwise.
+ */
+export function mapSdkMessage(msg: SDKMessage, state: ClaudeSdkMapState): AgentEvent[] {
+  switch (msg.type) {
+    case 'stream_event':
+      return mapStreamEvent(msg.event, state);
+    case 'assistant':
+      return mapFinalAssistant(msg.message.content, state);
+    default:
+      // system/init, status, result, hooks, task_*, etc. — no turn content here.
+      // (The backend reads session_id off the init message and usage/cost off the
+      // result message directly; neither produces a renderable AgentEvent.)
+      return [];
+  }
+}
+
+/** Live partial-stream delta → AgentEvent(s). */
+function mapStreamEvent(event: StreamEvent, state: ClaudeSdkMapState): AgentEvent[] {
+  switch (event.type) {
+    case 'content_block_start': {
+      const block = event.content_block;
+      if (block.type === 'tool_use') {
+        const snap: AcpToolSnapshot = {
+          toolCallId: block.id,
+          title: block.name,
+          kind: null,
+          status: 'in_progress',
+          rawInput: block.input ?? undefined,
+          rawOutput: undefined,
+        };
+        state.snapshots.set(block.id, snap);
+        state.toolByIndex.set(event.index, { id: block.id, name: block.name, jsonBuf: '' });
+        return [{ type: 'tool_call', toolCall: snap }];
+      }
+      return [];
+    }
+    case 'content_block_delta': {
+      const delta = event.delta;
+      if (delta.type === 'text_delta') {
+        return delta.text ? [{ type: 'text', text: delta.text }] : [];
+      }
+      if (delta.type === 'thinking_delta') {
+        return delta.thinking ? [{ type: 'reasoning', text: delta.thinking }] : [];
+      }
+      if (delta.type === 'input_json_delta') {
+        // Buffer the tool's streamed args under its block index; no event yet —
+        // the assembled input rides the terminal tool_update (or the final block).
+        const t = state.toolByIndex.get(event.index);
+        if (t) t.jsonBuf += delta.partial_json ?? '';
+        return [];
+      }
+      // signature_delta / citations_delta / compaction_delta — nothing to render.
+      return [];
+    }
+    case 'content_block_stop': {
+      // Close out a streamed tool block: parse its buffered JSON args and emit a
+      // tool_update carrying the assembled input. The final assistant message will
+      // restate the same block, but its snapshot is dedup-merged (same id) so this
+      // is harmless — we emit here so a tool's input renders even if the assistant
+      // message is delayed/dropped.
+      const t = state.toolByIndex.get(event.index);
+      if (!t) return [];
+      state.toolByIndex.delete(event.index);
+      const prev = state.snapshots.get(t.id);
+      const snap: AcpToolSnapshot = {
+        toolCallId: t.id,
+        title: prev?.title ?? t.name,
+        kind: null,
+        status: 'in_progress',
+        rawInput: parseJsonOr(t.jsonBuf, prev?.rawInput),
+        rawOutput: undefined,
+      };
+      state.snapshots.set(t.id, snap);
+      return [{ type: 'tool_update', toolCall: snap }];
+    }
+    default:
+      // message_start / message_delta / message_stop — turn framing, no content.
+      return [];
+  }
+}
+
+/**
+ * Final assistant message content blocks. Text/thinking are post-hoc repeats of
+ * the partial stream → dropped (dedup). Only tool_use blocks emit a terminal
+ * tool_update carrying the complete `input`.
+ */
+function mapFinalAssistant(content: ContentBlock[], state: ClaudeSdkMapState): AgentEvent[] {
+  const out: AgentEvent[] = [];
+  for (const block of content) {
+    if (block.type === 'tool_use') {
+      const prev = state.snapshots.get(block.id);
+      const snap: AcpToolSnapshot = {
+        toolCallId: block.id,
+        title: prev?.title ?? block.name,
+        kind: null,
+        status: 'completed',
+        rawInput: block.input ?? prev?.rawInput,
+        rawOutput: undefined,
+      };
+      state.snapshots.set(block.id, snap);
+      out.push({ type: 'tool_update', toolCall: snap });
+    }
+    // text / thinking / redacted_thinking blocks: already streamed via partials.
+  }
+  return out;
+}
+
+/** Parse a buffered JSON string; fall back to a prior value on empty/invalid. */
+function parseJsonOr(buf: string, fallback: unknown): unknown {
+  const s = buf.trim();
+  if (!s) return fallback;
+  try {
+    return JSON.parse(s);
+  } catch {
+    return fallback;
+  }
+}

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

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

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

@@ -0,0 +1,364 @@
+/**
+ * claude-sdk-sessionstore #9 (Part 2) — ClaudeSdkBackend.
+ *
+ * A warm, resumable backend for the `claude` agent built on the Claude Agent SDK
+ * (`@anthropic-ai/claude-agent-sdk`), implementing the Phase-0 `AgentBackend`
+ * contract (same shape as `WarmAcpBackend` / `OpenCodeServerBackend`). One
+ * persistent `query()` per (chat, agent) session, driven in STREAMING-INPUT mode:
+ * the `prompt` is a pushable `AsyncIterable<SDKUserMessage>` that stays open across
+ * turns, so the SDK subprocess + conversation stay warm between `prompt()` calls
+ * until `closeSession`/`dispose`.
+ *
+ * ⚠ LIVE PUMP IS HOST-ONLY. The actual streaming turn needs the real `claude`
+ * binary + ANTHROPIC auth on a host — it CANNOT run in the dev container. This file
+ * is written against the REAL SDK types so it TYPECHECKS, and the PURE pieces (the
+ * `mapSdkMessage` mapper + the `createPushable` queue) are unit-tested. Routing to
+ * this backend is gated behind `CLAUDE_SDK_BACKEND` (default OFF) so production
+ * claude stays on the working PTY path until a host smoke validates the pump +
+ * cross-turn resume.
+ *
+ * Lifecycle (mirrors warm-acp.ts / opencode-server.ts):
+ *   - `ensureSession`: resolve the resume id from `agent_sessions(chat_id,'claude')`
+ *     and (re)build the single `query()` if not already live. The SDK's own
+ *     `sessionStore` (Part 1 PostgresSessionStore) materializes the transcript on
+ *     resume; `options.resume` carries the provider session id.
+ *   - `prompt`: push ONE user message onto the open queue, iterate the generator,
+ *     map each `SDKMessage` → `AgentEvent`s via `mapSdkMessage`, forward to
+ *     `ctx.onEvent`, and resolve when the turn's `result` message lands. Capture the
+ *     `session_id` from the `init` message and persist it to `agent_sessions`;
+ *     accumulate `result.usage` / `total_cost_usd` onto the row (mirrors opencode U.6).
+ *   - `closeSession` / `dispose`: close the queue + dispose the query generator.
+ *   - A thrown error or `result.subtype==='error*'` marks `agent_sessions.status='crashed'`.
+ *
+ * Turn serialization: like warm-acp, exactly one turn is in flight at a time on a
+ * given backend (the dispatcher's per-session `inflight` map enforces this upstream;
+ * `isBusy()` reports it so the pool never evicts mid-turn).
+ */
+import { query, type Query, type SDKMessage, type SDKUserMessage, type Options } from '@anthropic-ai/claude-agent-sdk';
+import type { FastifyBaseLogger } from 'fastify';
+import type { Sql } from '../../db.js';
+import { PostgresSessionStore } from './claude-session-store.js';
+import { createPushable, type Pushable } from './pushable-iterable.js';
+import { mapSdkMessage, createClaudeSdkMapState, type ClaudeSdkMapState } from './claude-sdk-map.js';
+import type {
+  AgentBackend,
+  AgentSessionHandle,
+  EnsureSessionOpts,
+  PromptCtx,
+  TurnResult,
+} from '../agent-backend.js';
+
+export interface ClaudeSdkBackendDeps {
+  sql: Sql;
+  log: FastifyBaseLogger;
+  /** The (chat, agent) this backend serves — its pool identity + DB key. */
+  chatId: string;
+  /** Always 'claude' today; kept explicit so the pool key + DB writes stay honest. */
+  agent: string;
+  /** Resolved `claude` binary path (available_agents.install_path); null → SDK default. */
+  installPath: string | null;
+}
+
+export class ClaudeSdkBackend implements AgentBackend {
+  readonly backend = 'claude_sdk' as const;
+
+  private readonly sql: Sql;
+  private readonly log: FastifyBaseLogger;
+  private readonly chatId: string;
+  private readonly agent: string;
+  private readonly installPath: string | null;
+  private readonly sessionStore: PostgresSessionStore;
+
+  /** The single persistent query() generator; null until the first turn builds it. */
+  private query: Query | null = null;
+  /** The open input queue feeding the generator one SDKUserMessage per turn. */
+  private input: Pushable<SDKUserMessage> | null = null;
+  /** The provider's own session id (resume token), captured from the init message. */
+  private agentSessionId: string | null = null;
+  /** Resolved model the live query() was built with; a change forces a rebuild. */
+  private builtModel: string | null = null;
+  /** True between prompt() start and settle. */
+  private busy = false;
+  private up = false;
+
+  constructor(deps: ClaudeSdkBackendDeps) {
+    this.sql = deps.sql;
+    this.log = deps.log;
+    this.chatId = deps.chatId;
+    this.agent = deps.agent;
+    this.installPath = deps.installPath;
+    this.sessionStore = new PostgresSessionStore(deps.sql);
+  }
+
+  /** §2: liveness for the health endpoint + dispatcher fallback decision. */
+  health(): 'up' | 'down' {
+    return this.up ? 'up' : 'down';
+  }
+
+  /** Phase 3: busy iff a turn is in flight (pool never evicts a busy backend). */
+  isBusy(): boolean {
+    return this.busy;
+  }
+
+  // ─── ensureSession: resolve resume id + (re)build the warm query ──────────────
+
+  async ensureSession(sessionId: string, opts: EnsureSessionOpts): Promise<AgentSessionHandle> {
+    // Resolve the resume token from the (chat_id, agent) row. A crashed row is not
+    // resumed (the SDK would fail to load a dead session); we create fresh.
+    const [row] = await this.sql<{ agent_session_id: string | null; status: string }[]>`
+      SELECT agent_session_id, status FROM agent_sessions
+      WHERE chat_id = ${opts.chatId} AND agent = ${opts.agent}
+    `;
+    const resumeId = row && row.status !== 'crashed' ? row.agent_session_id : null;
+
+    // (Re)build the warm query if there is none, or the model changed (the SDK can
+    // change model mid-session via setModel, but a fresh build is simplest + matches
+    // opencode's config-drift → fresh-session rule). The query stays alive across
+    // turns; only closeSession/dispose tears it down.
+    if (!this.query || this.builtModel !== opts.model) {
+      await this.teardownQuery();
+      this.buildQuery(opts.worktreePath, opts.model, resumeId);
+    }
+
+    // Seed the in-memory resume id from the DB so a handle built before the first
+    // turn's init message still carries the last-known token. The init message
+    // overwrites it with the authoritative current id during the turn.
+    if (this.agentSessionId == null) this.agentSessionId = resumeId;
+
+    // Upsert the agent_sessions row (backend='claude_sdk'). agent_session_id may be
+    // null until the first turn captures it from the init message; prompt() updates it.
+    await this.sql`
+      INSERT INTO agent_sessions
+        (chat_id, session_id, worktree_id, agent, backend, agent_session_id, server_port, status, last_active_at)
+      VALUES
+        (${opts.chatId}, ${sessionId}, ${opts.worktreeId}, ${opts.agent}, 'claude_sdk', ${this.agentSessionId}, NULL, 'active', clock_timestamp())
+      ON CONFLICT (chat_id, agent) DO UPDATE SET
+        session_id = EXCLUDED.session_id,
+        worktree_id = EXCLUDED.worktree_id,
+        backend = 'claude_sdk',
+        agent_session_id = COALESCE(EXCLUDED.agent_session_id, agent_sessions.agent_session_id),
+        server_port = NULL,
+        status = 'active',
+        last_active_at = clock_timestamp()
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: opts.chatId, agent: opts.agent }, 'claude-sdk: agent_sessions upsert failed (non-fatal)');
+    });
+
+    return {
+      sessionId,
+      agent: opts.agent,
+      backend: 'claude_sdk',
+      chatId: opts.chatId,
+      worktreeId: opts.worktreeId,
+      agentSessionId: this.agentSessionId,
+      serverPort: null,
+    };
+  }
+
+  /** Build the persistent query() in streaming-input mode. Lazy — no subprocess
+   *  work happens until the generator is first iterated in prompt(). */
+  private buildQuery(worktreePath: string, model: string, resumeId: string | null): void {
+    const input = createPushable<SDKUserMessage>();
+    const options: Options = {
+      sessionStore: this.sessionStore,
+      cwd: worktreePath,
+      // Stream partial assistant messages so text/thinking/tool deltas arrive live
+      // (the mapper reads them; without this only terminal messages land).
+      includePartialMessages: true,
+      ...(model ? { model } : {}),
+      ...(resumeId ? { resume: resumeId } : {}),
+      ...(this.installPath ? { pathToClaudeCodeExecutable: this.installPath } : {}),
+      // ANTHROPIC auth/env must reach the child; inherit the process env (host concern).
+      env: process.env as Record<string, string>,
+    };
+    this.input = input;
+    this.query = query({ prompt: input.iterable, options });
+    this.builtModel = model;
+    this.up = true;
+    this.log.info({ chatId: this.chatId, agent: this.agent, model, resume: resumeId ?? null }, 'claude-sdk: warm query built');
+  }
+
+  // ─── prompt: push one user message + drain the generator until result ─────────
+
+  async prompt(handle: AgentSessionHandle, input: string, ctx: PromptCtx): Promise<TurnResult> {
+    if (!this.query || !this.input) {
+      // ensureSession should have built it; rebuild defensively (e.g. evicted/raced).
+      this.buildQuery(ctx.worktreePath, ctx.model, handle.agentSessionId);
+    }
+    const gen = this.query!;
+    const queue = this.input!;
+
+    if (ctx.signal.aborted) return { ok: false, error: 'aborted' };
+
+    this.busy = true;
+    const state: ClaudeSdkMapState = createClaudeSdkMapState();
+    // Per-turn abort: interrupt the in-flight query on the SAME generator (never
+    // tear down the warm query — that's the pool's lifetime). The generator then
+    // emits its terminal result and the drain loop exits.
+    let aborted = false;
+    const onAbort = () => {
+      if (aborted) return;
+      aborted = true;
+      void gen.interrupt().catch(() => {});
+    };
+    ctx.signal.addEventListener('abort', onAbort, { once: true });
+
+    // Push the turn's user message onto the open queue. session_id is optional on
+    // the wire; the SDK manages it via resume + the init message.
+    const userMsg: SDKUserMessage = {
+      type: 'user',
+      message: { role: 'user', content: input },
+      parent_tool_use_id: null,
+      ...(handle.agentSessionId ? { session_id: handle.agentSessionId } : {}),
+    };
+    queue.push(userMsg);
+
+    try {
+      for await (const msg of gen) {
+        // Capture the provider session id from the init message (authoritative).
+        if (msg.type === 'system' && msg.subtype === 'init' && msg.session_id) {
+          if (this.agentSessionId !== msg.session_id) {
+            this.agentSessionId = msg.session_id;
+            await this.persistAgentSessionId(msg.session_id);
+          }
+        }
+        // The result message ends THIS turn (it does not close the generator —
+        // streaming-input keeps it alive for the next pushed message).
+        if (msg.type === 'result') {
+          await this.accumulateUsage(msg);
+          const ok = msg.subtype === 'success' && !aborted;
+          if (!ok) {
+            // error_during_execution / error_max_turns / aborted → crashed row.
+            await this.markCrashed();
+          } else {
+            await this.markIdle();
+          }
+          if (aborted) return { ok: false, error: 'aborted' };
+          return ok
+            ? { ok: true }
+            : { ok: false, error: resultErrorMessage(msg) };
+        }
+        // Map renderable content → AgentEvents for the dispatcher's onEvent.
+        for (const ev of mapSdkMessage(msg, state)) {
+          ctx.onEvent(ev);
+        }
+      }
+      // Generator ended without a result message (e.g. it was disposed) — treat as
+      // a non-fatal incomplete turn so the dispatcher still finalizes the row.
+      if (aborted) return { ok: false, error: 'aborted' };
+      return { ok: false, error: 'claude-sdk: query ended before result' };
+    } catch (err) {
+      if (aborted) return { ok: false, error: 'aborted' };
+      await this.markCrashed();
+      return { ok: false, error: errMsg(err) };
+    } finally {
+      ctx.signal.removeEventListener('abort', onAbort);
+      this.busy = false;
+    }
+  }
+
+  // ─── persistence helpers ──────────────────────────────────────────────────────
+
+  private async persistAgentSessionId(id: string): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions
+      SET agent_session_id = ${id}, last_active_at = clock_timestamp()
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: this.chatId }, 'claude-sdk: failed to persist agent_session_id (non-fatal)');
+    });
+  }
+
+  /**
+   * Accumulate the turn's usage/cost onto the (chat_id, agent) row — mirrors the
+   * opencode U.6 running-total pattern. The SDK reports usage once per turn on the
+   * result message (not per step), so this fires once per prompt(). Cache read/write
+   * input tokens fold into `input_tokens`; usage telemetry never fails a turn.
+   */
+  private async accumulateUsage(result: Extract<SDKMessage, { type: 'result' }>): Promise<void> {
+    const u = result.usage;
+    const input = num(u?.input_tokens) + num(u?.cache_read_input_tokens) + num(u?.cache_creation_input_tokens);
+    const output = num(u?.output_tokens);
+    const cost = numF(result.total_cost_usd);
+    if (input === 0 && output === 0 && cost === 0) return;
+    await this.sql`
+      UPDATE agent_sessions SET
+        input_tokens = input_tokens + ${input},
+        output_tokens = output_tokens + ${output},
+        cost = cost + ${cost}
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch((err) => {
+      this.log.warn({ err: errMsg(err), chatId: this.chatId }, 'claude-sdk: failed to persist usage (non-fatal)');
+    });
+  }
+
+  private async markIdle(): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions SET status = 'idle', last_active_at = clock_timestamp()
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch(() => {});
+  }
+
+  private async markCrashed(): Promise<void> {
+    await this.sql`
+      UPDATE agent_sessions SET status = 'crashed'
+      WHERE chat_id = ${this.chatId} AND agent = ${this.agent}
+    `.catch(() => {});
+  }
+
+  // ─── teardown ────────────────────────────────────────────────────────────────
+
+  async closeSession(handle: AgentSessionHandle): Promise<void> {
+    await this.teardownQuery();
+    await this.sql`
+      UPDATE agent_sessions SET status = 'closed'
+      WHERE chat_id = ${handle.chatId} AND agent = ${handle.agent}
+    `.catch(() => {});
+  }
+
+  async dispose(): Promise<void> {
+    await this.teardownQuery();
+  }
+
+  /** Close the input queue + dispose the generator. Idempotent. */
+  private async teardownQuery(): Promise<void> {
+    this.up = false;
+    this.busy = false;
+    const q = this.query;
+    const queue = this.input;
+    this.query = null;
+    this.input = null;
+    this.builtModel = null;
+    queue?.close();
+    if (q) {
+      // return() ends the AsyncGenerator and lets the SDK clean up its subprocess.
+      await q.return(undefined).catch(() => {});
+    }
+  }
+}
+
+// ─── helpers ──────────────────────────────────────────────────────────────────
+
+/** Coerce to a non-negative finite integer (tokens). */
+function num(v: unknown): number {
+  const x = typeof v === 'number' ? v : Number(v);
+  return Number.isFinite(x) && x > 0 ? Math.round(x) : 0;
+}
+
+/** Coerce to a non-negative finite float (cost USD). */
+function numF(v: unknown): number {
+  const x = typeof v === 'number' ? v : Number(v);
+  return Number.isFinite(x) && x > 0 ? x : 0;
+}
+
+/** Build a human-readable error from an SDK error-result message. */
+function resultErrorMessage(result: Extract<SDKMessage, { type: 'result' }>): string {
+  if (result.subtype === 'success') return 'ok';
+  const errs = (result as { errors?: string[] }).errors;
+  if (Array.isArray(errs) && errs.length > 0) return `${result.subtype}: ${errs.join('; ')}`;
+  return result.subtype;
+}
+
+function errMsg(e: unknown): string {
+  return e instanceof Error ? e.message : String(e);
+}

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

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

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

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

apps/coder/src/services/dispatcher.ts

@@ -16,8 +16,12 @@ import { snapshotToWireToolCall, type AcpToolSnapshot } from './acp-tool-snapsho
 import { agentPool, OPENCODE_POOL_KEY } from './agent-pool.js';
 import { OpenCodeServerBackend } from './backends/opencode-server.js';
 import { WarmAcpBackend } from './backends/warm-acp.js';
+import { ClaudeSdkBackend } from './backends/claude-sdk.js';
 import { shouldUseWarmBackend } from './backends/warm-acp-routing.js';
+import { shouldUseClaudeSdk } from './backends/claude-sdk-routing.js';
 import type { AgentBackend, AgentEvent } from './agent-backend.js';
+import { publishAgentStatus } from './agent-status-publish.js';
+import type { AgentStatus } from './normalize-agent-status.js';
 
 interface InferenceRunner {
   enqueue: (sessionId: string, chatId: string, assistantId: string, user: string) => void;
@@ -64,6 +68,21 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
     return task.session_id ?? `task:${task.id}`;
   }
 
+  // agent-status-normalize (#10): publish a normalized per-(chat,agent) status on
+  // the session channel. Every external-agent path (warm-acp / opencode / claude-sdk /
+  // pty one-shot) reports `working` at turn start, `idle` on clean completion, and
+  // `error` on the failure path through this single helper so the four paths stay
+  // DRY and consistent. Best-effort — publishAgentStatus never throws.
+  function emitAgentStatus(
+    sessionId: string,
+    chatId: string,
+    agent: string,
+    status: AgentStatus,
+    reason: string,
+  ): void {
+    publishAgentStatus(broker.publishFrame, sessionId, chatId, agent, status, reason);
+  }
+
   async function poll(): Promise<void> {
     // `polling` serializes poll() execution itself (timer + NOTIFY can fire
     // concurrently) so we never double-select a task. It does NOT serialize task
@@ -131,6 +150,12 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         // existing one-shot worktree-per-task ACP/PTY path untouched.
         if (task.agent === 'opencode') {
           await runOpenCodeServerTask(task, agentRow.install_path);
+        } else if (shouldUseClaudeSdk(task)) {
+          // claude-sdk-sessionstore #9 (Part 2): env-flagged (CLAUDE_SDK_BACKEND, default
+          // OFF) warm Claude-SDK backend for chat-tab claude tasks. When the flag is off
+          // (production default) this predicate returns false and claude falls through to
+          // the UNCHANGED one-shot PTY runExternalAgent path below.
+          await runClaudeSdkTask(task, agentRow.install_path);
         } else if (shouldUseWarmBackend(task)) {
           await runWarmAcpTask(task, agentRow.install_path);
         } else {
@@ -290,6 +315,11 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
     // Create an abort controller for this task
     const ac = new AbortController();
 
+    // #10: hoisted above the try so the catch block can report `error` status with
+    // the (chat, agent) key. Empty until resolved below; guarded before use.
+    let sessionId = '';
+    let chatId = '';
+
     try {
       // Mark running
       await sql`
@@ -298,9 +328,6 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         WHERE id = ${taskId}
       `;
 
-      let sessionId: string;
-      let chatId: string;
-
       if (task.session_id) {
         sessionId = task.session_id;
         const chats = await sql<{ id: string }[]>`
@@ -376,6 +403,9 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         role: 'assistant',
       } as WsFrame);
 
+      // #10: external-agent turn begins.
+      emitAgentStatus(sessionId, chatId, agent, 'working', 'turn_start');
+
       const manifestCommands = getManifestCommands(agent);
       if (manifestCommands.length > 0) {
         setTaskCommands(taskId, manifestCommands);
@@ -550,6 +580,8 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         WHERE id = ${taskId}
       `;
       log.info({ taskId, agent, costTokens: extCostTokens }, 'dispatcher: task completed (external)');
+      // #10: external-agent turn completed cleanly.
+      emitAgentStatus(sessionId, chatId, agent, 'idle', 'turn_complete');
       clearTaskCommands(taskId);
 
     } catch (err) {
@@ -562,6 +594,11 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         WHERE id = ${taskId}
       `.catch(() => {});
 
+      // #10: external-agent turn failed/crashed. chatId may be unbound if the throw
+      // preceded its assignment — guard so the status publish never masks the real
+      // error.
+      if (chatId) emitAgentStatus(sessionId, chatId, agent, 'error', 'failed');
+
       // Best-effort cleanup
       await cleanupWorktree(projectPath, taskId);
       clearTaskCommands(taskId);
@@ -616,6 +653,10 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
 
     const ac = new AbortController();
 
+    // #10: hoisted so the catch can report `error` with the (chat, agent) key.
+    let sessionId = '';
+    let chatId = '';
+
     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
@@ -632,8 +673,6 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
       // 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;
@@ -706,6 +745,9 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         role: 'assistant',
       } as WsFrame);
 
+      // #10: opencode-server turn begins.
+      emitAgentStatus(sessionId, chatId, agent, 'working', 'turn_start');
+
       const manifestCommands = getManifestCommands(agent);
       if (manifestCommands.length > 0) {
         setTaskCommands(taskId, manifestCommands);
@@ -865,6 +907,14 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         WHERE id = ${taskId}
       `;
       log.info({ taskId, agent, finalState, costTokens: extCostTokens }, 'dispatcher: task finished (opencode server)');
+      // #10: clean completion → idle; backend-reported failure → error.
+      emitAgentStatus(
+        sessionId,
+        chatId,
+        agent,
+        result.ok ? 'idle' : 'error',
+        result.ok ? 'turn_complete' : 'failed',
+      );
       clearTaskCommands(taskId);
     } catch (err) {
       const errMsg = err instanceof Error ? err.message : String(err);
@@ -874,6 +924,8 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         SET state = 'failed', ended_at = clock_timestamp(), output_summary = ${errMsg.slice(0, 500)}
         WHERE id = ${taskId}
       `.catch(() => {});
+      // #10: turn crashed.
+      if (chatId) emitAgentStatus(sessionId, chatId, agent, 'error', 'crashed');
       clearTaskCommands(taskId);
       // No worktree cleanup (persistent); backend stays warm for the next turn.
     }
@@ -974,6 +1026,9 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         role: 'assistant',
       } as WsFrame);
 
+      // #10: warm-ACP turn begins.
+      emitAgentStatus(sessionId, chatId, agent, 'working', 'turn_start');
+
       const manifestCommands = getManifestCommands(agent);
       if (manifestCommands.length > 0) {
         setTaskCommands(taskId, manifestCommands);
@@ -1115,6 +1170,14 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         WHERE id = ${taskId}
       `;
       log.info({ taskId, agent, finalState }, 'dispatcher: task finished (warm ACP)');
+      // #10: clean completion → idle; backend-reported failure → error.
+      emitAgentStatus(
+        sessionId,
+        chatId,
+        agent,
+        result.ok ? 'idle' : 'error',
+        result.ok ? 'turn_complete' : 'failed',
+      );
       clearTaskCommands(taskId);
     } catch (err) {
       const errMsg = err instanceof Error ? err.message : String(err);
@@ -1124,6 +1187,262 @@ export function createDispatcher(deps: Deps): { start(): void; stop(): Promise<v
         SET state = 'failed', ended_at = clock_timestamp(), output_summary = ${errMsg.slice(0, 500)}
         WHERE id = ${taskId}
       `.catch(() => {});
+      // #10: turn crashed.
+      emitAgentStatus(sessionId, chatId, agent, 'error', 'crashed');
+      clearTaskCommands(taskId);
+      // No worktree cleanup (persistent); backend stays warm for the next turn.
+    }
+  }
+
+  // ─── Path B (claude SDK): warm Claude-SDK backend (v2.6 #9 Part 2) ───────────
+
+  // Claude-SDK backends are per (chat, agent) — each owns ONE persistent query()
+  // generator driven in streaming-input mode. Pool key = chatId (secondary = agent),
+  // mirroring agent_sessions' (chat_id, agent) PK + the warm-ACP pooling.
+  function getClaudeSdkBackend(chatId: string, agent: string, installPath: string | null): ClaudeSdkBackend {
+    let backend = agentPool.get(chatId, agent);
+    if (!backend) {
+      backend = new ClaudeSdkBackend({ sql, log, chatId, agent, installPath });
+      agentPool.register(chatId, agent, backend);
+    }
+    return backend as ClaudeSdkBackend;
+  }
+
+  async function runClaudeSdkTask(
+    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!;
+    // shouldUseClaudeSdk 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 — claude SDK)');
+
+    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 = ${taskId}
+      `;
+
+      // Persistent, session-keyed worktree (shared across turns + agents; NOT torn
+      // down per turn — Phase 3 reaps it). Same as the opencode/warm-ACP paths so a
+      // chat that switches agents shares one worktree.
+      const { worktreeId, worktreePath, baseCommit } = await ensureSessionWorktree(sql, projectPath, sessionId, {
+        signal: ac.signal,
+      });
+      log.info({ taskId, worktreePath }, 'dispatcher: session worktree ready (claude SDK)');
+
+      const [assistantMsg] = await sql<{ id: string }[]>`
+        INSERT INTO messages (session_id, chat_id, role, content, status, created_at)
+        VALUES (${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).
+      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);
+
+      // #10: claude-SDK turn begins.
+      emitAgentStatus(sessionId, chatId, agent, 'working', 'turn_start');
+
+      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 warm-ACP /
+      // opencode paths emit. This boundary attaches message_id/chat_id.
+      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 = getClaudeSdkBackend(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 ?? 'claude SDK 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/ACP.
+      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 (claude SDK)');
+      } else {
+        log.info({ taskId }, 'dispatcher: no changes detected in session worktree (claude SDK)');
+      }
+
+      // 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 (claude SDK)');
+      // #10: clean completion → idle; backend-reported failure → error.
+      emitAgentStatus(
+        sessionId,
+        chatId,
+        agent,
+        result.ok ? 'idle' : 'error',
+        result.ok ? 'turn_complete' : 'failed',
+      );
+      clearTaskCommands(taskId);
+    } catch (err) {
+      const errMsg = err instanceof Error ? err.message : String(err);
+      log.error({ taskId, agent, err: errMsg }, 'dispatcher: claude SDK error');
+      await sql`
+        UPDATE tasks
+        SET state = 'failed', ended_at = clock_timestamp(), output_summary = ${errMsg.slice(0, 500)}
+        WHERE id = ${taskId}
+      `.catch(() => {});
+      // #10: turn crashed.
+      emitAgentStatus(sessionId, chatId, agent, 'error', 'crashed');
       clearTaskCommands(taskId);
       // No worktree cleanup (persistent); backend stays warm for the next turn.
     }

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

@@ -0,0 +1,92 @@
+/**
+ * normalize-agent-status (#10) — clean-room vendor-event → bucket mapping.
+ *
+ * Different coding agents (claude, opencode, codex/gemini, goose, qwen) emit
+ * lifecycle hook events under inconsistent names: PascalCase (`SessionStart`),
+ * snake_case (`session_start`), camelCase (`sessionStart`), and a handful of
+ * provider-specific approval events (`exec_approval_request`). This module
+ * collapses every known event name into one of three coarse signals:
+ *
+ *   working  — the agent is actively progressing a turn
+ *   blocked  — the agent is waiting on a human (permission / approval / question)
+ *   done     — the turn / session ended cleanly
+ *
+ * `null` is returned for anything unrecognized so callers can ignore noise.
+ *
+ * Built now for the scoped status-publish, but specifically shaped for reuse by
+ * the documented config-injection follow-on: a future notify-hook injected into
+ * each agent's native config will POST the RAW vendor event name to a BooCoder
+ * endpoint, which runs this helper to derive the normalized status. The names
+ * below are facts about each agent's hook surface — not copied vendor code.
+ */
+
+export type AgentStatus = 'working' | 'blocked' | 'idle' | 'error';
+
+/** The coarse signal a raw vendor event collapses to. */
+export type AgentEventBucket = 'working' | 'blocked' | 'done';
+
+// Each bucket lists the canonical vendor event names. Lookup is
+// case-insensitive AND separator-insensitive (snake_case / camelCase /
+// PascalCase all fold to the same key), so we normalize the raw input the same
+// way before matching rather than enumerating every spelling here.
+const WORKING_EVENTS = [
+  'SessionStart',
+  'UserPromptSubmit',
+  'UserPromptSubmitted',
+  'PostToolUse',
+  'PostToolUseFailure',
+  'BeforeAgent',
+  'AfterTool',
+  'task_started',
+] as const;
+
+const BLOCKED_EVENTS = [
+  'PreToolUse',
+  'Notification',
+  'PermissionRequest',
+  'exec_approval_request',
+  'apply_patch_approval_request',
+  'request_user_input',
+] as const;
+
+const DONE_EVENTS = [
+  'Stop',
+  'AfterAgent',
+  'SessionEnd',
+  'task_complete',
+  'agent-turn-complete',
+] as const;
+
+/**
+ * Fold a raw event name to a separator/case-insensitive key:
+ * strip every non-alphanumeric character and lowercase. So `post_tool_use`,
+ * `postToolUse`, `PostToolUse`, and `POST-TOOL-USE` all map to `posttooluse`.
+ */
+function foldKey(raw: string): string {
+  return raw.replace(/[^a-z0-9]/gi, '').toLowerCase();
+}
+
+function buildLookup(
+  groups: ReadonlyArray<readonly [AgentEventBucket, readonly string[]]>,
+): Map<string, AgentEventBucket> {
+  const map = new Map<string, AgentEventBucket>();
+  for (const [bucket, names] of groups) {
+    for (const name of names) map.set(foldKey(name), bucket);
+  }
+  return map;
+}
+
+const EVENT_LOOKUP = buildLookup([
+  ['working', WORKING_EVENTS],
+  ['blocked', BLOCKED_EVENTS],
+  ['done', DONE_EVENTS],
+]);
+
+/**
+ * Map a raw vendor hook-event name to its normalized bucket, or `null` when the
+ * name is unknown / undefined. Case- and separator-insensitive.
+ */
+export function normalizeAgentEvent(raw: string | undefined): AgentEventBucket | null {
+  if (!raw) return null;
+  return EVENT_LOOKUP.get(foldKey(raw)) ?? null;
+}

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

@@ -38,6 +38,12 @@ export const PROVIDERS: ProviderDef[] = [
   },
   {
     name: 'claude',
+    // transport stays 'pty' — the DEFAULT dispatch path (one-shot `claude
+    // --output-format stream-json`). claude-sdk-sessionstore #9 (Part 2) adds a warm
+    // Claude-Agent-SDK backend (services/backends/claude-sdk.ts) routed ONLY when the
+    // `CLAUDE_SDK_BACKEND` env flag is truthy AND the task is a chat tab; with the flag
+    // off (production default) claude always uses this PTY path, so the transport label
+    // is left unchanged. Flip the env var on a host (after a live smoke) to opt in.
     label: 'Claude Code',
     transport: 'pty',
     modelSource: 'static',

apps/coder/vitest.config.ts

@@ -5,5 +5,11 @@ export default defineConfig({
     environment: 'node',
     globals: false,
     include: ['src/**/__tests__/**/*.test.ts'],
+    // DB-integration suites (checkpoints, claude-session-store, reconnect, etc.)
+    // each apply the full schema in beforeAll against the one shared dev DB; running
+    // test files in parallel makes those concurrent DDL applies deadlock under
+    // DATABASE_URL. Serialize file execution — the suites are fast, so the cost is
+    // negligible and the default (no-DATABASE_URL) run is unaffected.
+    fileParallelism: false,
   },
 });

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

@@ -7,6 +7,8 @@ import {
   select,
   buildPrompt,
   buildHeadPayload,
+  deriveFilesRead,
+  buildFilesReadContext,
   type CompactionMessage,
 } from '../compaction.js';
 import { SUMMARY_TEMPLATE } from '../compaction-prompt.js';
@@ -321,3 +323,105 @@ describe('buildHeadPayload reasoning render', () => {
     expect(out[1]!.content).not.toContain('<reasoning>');
   });
 });
+
+// ---- buildHeadPayload sentinel stripping (#12) -------------------------------
+
+describe('buildHeadPayload strips all UI sentinels', () => {
+  it('drops cap_hit, doom_loop, and mistake_recovery system rows', () => {
+    const out = buildHeadPayload([
+      mkMsg('user', 'do the thing'),
+      mkMsg('system', 'budget reached', { metadata: { kind: 'cap_hit' } }),
+      mkMsg('system', 'looping', { metadata: { kind: 'doom_loop' } }),
+      mkMsg('system', 'repeated errors', { metadata: { kind: 'mistake_recovery' } }),
+      mkMsg('assistant', 'answer'),
+    ]);
+    // Only the user + assistant rows survive; all three sentinels stripped.
+    expect(out).toHaveLength(2);
+    expect(out[0]!.role).toBe('user');
+    expect(out[1]!.role).toBe('assistant');
+  });
+
+  it('keeps a non-sentinel system row (e.g. compact bridge) untouched', () => {
+    const out = buildHeadPayload([
+      mkMsg('system', 'legacy compact', { kind: 'compact', metadata: null }),
+      mkMsg('user', 'q'),
+    ]);
+    expect(out[0]!.role).toBe('system');
+    expect(out[0]!.content).toBe('legacy compact');
+  });
+});
+
+// ---- file-provenance ledger (#12, Part B) -----------------------------------
+
+describe('deriveFilesRead', () => {
+  it('returns [] when the head has no read-tool calls', () => {
+    expect(deriveFilesRead([mkMsg('user', 'hi'), mkMsg('assistant', 'hello')])).toEqual([]);
+  });
+
+  it('extracts the path arg from view_file / list_dir / grep / find_files', () => {
+    const head = [
+      mkMsg('assistant', '', {
+        tool_calls: [
+          { id: 'c1', name: 'view_file', args: { path: 'src/index.ts' } },
+          { id: 'c2', name: 'list_dir', args: { path: 'src' } },
+          { id: 'c3', name: 'grep', args: { pattern: 'TODO', path: 'apps' } },
+          { id: 'c4', name: 'find_files', args: { pattern: '**/*.ts', path: 'lib' } },
+        ],
+      }),
+    ];
+    expect(deriveFilesRead(head)).toEqual(['apps', 'lib', 'src', 'src/index.ts']);
+  });
+
+  it('dedupes and sorts paths across multiple assistant turns', () => {
+    const head = [
+      mkMsg('assistant', '', { tool_calls: [{ id: 'c1', name: 'view_file', args: { path: 'b.ts' } }] }),
+      mkMsg('assistant', '', { tool_calls: [{ id: 'c2', name: 'view_file', args: { path: 'a.ts' } }] }),
+      mkMsg('assistant', '', { tool_calls: [{ id: 'c3', name: 'view_file', args: { path: 'b.ts' } }] }),
+    ];
+    expect(deriveFilesRead(head)).toEqual(['a.ts', 'b.ts']);
+  });
+
+  it('ignores non-read tools and grep calls without a path arg', () => {
+    const head = [
+      mkMsg('assistant', '', {
+        tool_calls: [
+          { id: 'c1', name: 'web_search', args: { query: 'x' } },
+          { id: 'c2', name: 'grep', args: { pattern: 'foo' } }, // no path → root, skipped
+          { id: 'c3', name: 'view_file', args: { path: 'kept.ts' } },
+        ],
+      }),
+    ];
+    expect(deriveFilesRead(head)).toEqual(['kept.ts']);
+  });
+
+  it('ignores read-tool calls on non-assistant rows', () => {
+    const head = [
+      mkMsg('user', '', { tool_calls: [{ id: 'c1', name: 'view_file', args: { path: 'nope.ts' } }] }),
+    ];
+    expect(deriveFilesRead(head)).toEqual([]);
+  });
+});
+
+describe('buildFilesReadContext', () => {
+  it('returns null when nothing was read (no empty section injected)', () => {
+    expect(buildFilesReadContext([mkMsg('user', 'hi')])).toBeNull();
+  });
+
+  it('formats a ## Files Read block with sorted bullet paths', () => {
+    const head = [
+      mkMsg('assistant', '', {
+        tool_calls: [
+          { id: 'c1', name: 'view_file', args: { path: 'z.ts' } },
+          { id: 'c2', name: 'view_file', args: { path: 'a.ts' } },
+        ],
+      }),
+    ];
+    expect(buildFilesReadContext(head)).toBe('## Files Read\n- a.ts\n- z.ts');
+  });
+});
+
+describe('SUMMARY_TEMPLATE includes the Files Read section (#12)', () => {
+  it('declares a ## Files Read section the model must maintain', () => {
+    expect(SUMMARY_TEMPLATE).toContain('## Files Read');
+  });
+});

apps/server/src/services/__tests__/mistake-tracker.test.ts

@@ -0,0 +1,164 @@
+import { describe, it, expect } from 'vitest';
+import {
+  MISTAKE_THRESHOLD,
+  freshMistakeState,
+  recordStep,
+  detectMistakePattern,
+  MISTAKE_RECOVERY_NOTE,
+  type FailureKind,
+} from '../inference/mistake-tracker.js';
+
+// ---- helpers ----------------------------------------------------------------
+// Replays a sequence of outcomes against a fresh state, returning the final
+// state so assertions can read .run / .nudges. The caller mimics turn.ts: after
+// each recordStep we consult detectMistakePattern and, if it returns 'nudge',
+// bump nudges + reset run (the loop's nudge-handling side effect).
+
+function replay(
+  outcomes: (FailureKind | 'success')[],
+  { applyNudge = false }: { applyNudge?: boolean } = {},
+) {
+  const state = freshMistakeState();
+  const decisions: (ReturnType<typeof detectMistakePattern>)[] = [];
+  for (const o of outcomes) {
+    recordStep(state, o);
+    const decision = detectMistakePattern(state);
+    decisions.push(decision);
+    if (applyNudge && decision === 'nudge') {
+      // Mirror turn.ts's nudge side effect: bump the counter, reset the streak.
+      state.nudges += 1;
+      state.run = [];
+    }
+  }
+  return { state, decisions };
+}
+
+// ---- fresh state ------------------------------------------------------------
+
+describe('freshMistakeState', () => {
+  it('starts with an empty run and zero nudges', () => {
+    const s = freshMistakeState();
+    expect(s.run).toEqual([]);
+    expect(s.nudges).toBe(0);
+  });
+});
+
+// ---- below threshold --------------------------------------------------------
+
+describe('detectMistakePattern — below threshold', () => {
+  it('returns null on a fresh state', () => {
+    expect(detectMistakePattern(freshMistakeState())).toBeNull();
+  });
+
+  it('returns null after fewer than MISTAKE_THRESHOLD failures', () => {
+    const { decisions } = replay(['zod_reject', 'exec_error']);
+    expect(decisions).toEqual([null, null]);
+  });
+});
+
+// ---- success reset ----------------------------------------------------------
+
+describe('recordStep — success resets', () => {
+  it("'success' clears both the run streak and the nudge counter", () => {
+    const state = freshMistakeState();
+    recordStep(state, 'zod_reject');
+    recordStep(state, 'exec_error');
+    state.nudges = 2; // simulate prior nudges
+    recordStep(state, 'success');
+    expect(state.run).toEqual([]);
+    expect(state.nudges).toBe(0);
+  });
+
+  it('a success mid-streak prevents the threshold from tripping', () => {
+    // fail, fail, success, fail, fail → streak never reaches 3.
+    const { decisions } = replay([
+      'zod_reject',
+      'exec_error',
+      'success',
+      'tool_not_found',
+      'permission_denied',
+    ]);
+    expect(decisions.every((d) => d === null)).toBe(true);
+  });
+});
+
+// ---- 3-streak nudge ---------------------------------------------------------
+
+describe('detectMistakePattern — nudge on 3-streak', () => {
+  it("returns 'nudge' the first time the streak reaches MISTAKE_THRESHOLD", () => {
+    const { decisions } = replay(['zod_reject', 'exec_error', 'tool_not_found']);
+    expect(decisions).toEqual([null, null, 'nudge']);
+  });
+
+  it("fires 'nudge' for a streak of identical kinds too (kind-agnostic)", () => {
+    const { decisions } = replay(['exec_error', 'exec_error', 'exec_error']);
+    expect(decisions[2]).toBe('nudge');
+  });
+});
+
+// ---- re-trip escalate -------------------------------------------------------
+
+describe('detectMistakePattern — escalate on re-trip', () => {
+  it("escalates when the streak re-trips after a nudge with no intervening success", () => {
+    // 3 fails → nudge (run reset, nudges=1), then 3 more fails → escalate.
+    const { decisions } = replay(
+      [
+        'zod_reject',
+        'exec_error',
+        'tool_not_found',
+        'permission_denied',
+        'exec_error',
+        'zod_reject',
+      ],
+      { applyNudge: true },
+    );
+    expect(decisions[2]).toBe('nudge');
+    expect(decisions[5]).toBe('escalate');
+  });
+
+  it("does NOT escalate if a success lands between the nudge and the next streak", () => {
+    const { decisions } = replay(
+      [
+        'zod_reject',
+        'exec_error',
+        'tool_not_found', // nudge here
+        'success', // clears nudges back to 0
+        'exec_error',
+        'zod_reject',
+        'tool_not_found', // 3-streak again → nudge, NOT escalate
+      ],
+      { applyNudge: true },
+    );
+    expect(decisions[2]).toBe('nudge');
+    expect(decisions[6]).toBe('nudge');
+    expect(decisions).not.toContain('escalate');
+  });
+});
+
+// ---- mixed kinds ------------------------------------------------------------
+
+describe('detectMistakePattern — mixed failure kinds', () => {
+  it('counts a streak of all five distinct kinds toward the threshold', () => {
+    const { state, decisions } = replay([
+      'zod_reject',
+      'tool_not_found',
+      'exec_error',
+    ]);
+    expect(decisions[2]).toBe('nudge');
+    expect(state.run).toEqual(['zod_reject', 'tool_not_found', 'exec_error']);
+  });
+});
+
+// ---- contract ---------------------------------------------------------------
+
+describe('MISTAKE_THRESHOLD + MISTAKE_RECOVERY_NOTE', () => {
+  it('threshold is a positive integer (tests assume 3)', () => {
+    expect(MISTAKE_THRESHOLD).toBeGreaterThan(0);
+    expect(Number.isInteger(MISTAKE_THRESHOLD)).toBe(true);
+  });
+
+  it('recovery note is a non-empty model-facing string', () => {
+    expect(typeof MISTAKE_RECOVERY_NOTE).toBe('string');
+    expect(MISTAKE_RECOVERY_NOTE.length).toBeGreaterThan(0);
+  });
+});

apps/server/src/services/compaction-prompt.ts

@@ -31,10 +31,16 @@ export const SUMMARY_TEMPLATE = `Output exactly the Markdown structure shown ins
 
 ## Relevant Files
 - [file or directory path: why it matters, or "(none)"]
+
+## Files Read
+- [file or directory path that has been read/searched this session, or "(none)"]
 </template>
 
 Rules:
 - Keep every section, even when empty.
 - Use terse bullets, not prose paragraphs.
 - Preserve exact file paths, commands, error strings, and identifiers when known.
+- For ## Files Read: this is a cumulative provenance ledger. MERGE the paths
+  listed in any "## Files Read" block provided below with those already in the
+  previous summary — never drop a previously-recorded path. Sort and dedupe.
 - Do not mention the summary process or that context was compacted.`;

apps/server/src/services/compaction.ts

@@ -181,6 +181,54 @@ export function select(
   };
 }
 
+// === file-provenance ledger (#12, Part B) ===
+
+// Read tools whose path/target arg names a file or directory that was read.
+// BooChat (apps/server) is read-only — there are no write tools, so the ledger
+// only ever has a "Files Read" side (apps/coder can add "Modified" later).
+const READ_TOOL_ARG: Record<string, string> = {
+  view_file: 'path',
+  list_dir: 'path',
+  grep: 'path',
+  find_files: 'path',
+};
+
+// Derive a deterministic, deduped, sorted list of file/dir paths read by the
+// HEAD messages being summarized. Pure — scans assistant tool_calls only; the
+// boundary (which messages are "head") is decided by select() at the call site.
+// We derive at compaction time rather than via a live accumulator because
+// TurnArgs resets per turn and would miss reads on non-compacting turns; the
+// head messages are the authoritative record of what was read in the window
+// being summarized. The result propagates forward as summary text across
+// compactions (the LLM merges it into ## Files Read), so a path read long ago
+// survives even after its originating messages are compacted out.
+export function deriveFilesRead(head: CompactionMessage[]): string[] {
+  const paths = new Set<string>();
+  for (const m of head) {
+    if (m.role !== 'assistant') continue;
+    if (!m.tool_calls) continue;
+    for (const tc of m.tool_calls) {
+      const argName = READ_TOOL_ARG[tc.name];
+      if (!argName) continue;
+      const raw = (tc.args as Record<string, unknown> | null)?.[argName];
+      if (typeof raw === 'string' && raw.trim().length > 0) {
+        paths.add(raw.trim());
+      }
+    }
+  }
+  return [...paths].sort();
+}
+
+// Format the derived paths as a deterministic ## Files Read block for injection
+// into buildPrompt's context array. Returns null when nothing was read (so we
+// don't inject an empty section). The summarizer merges this into the rolling
+// summary's ## Files Read section per the SUMMARY_TEMPLATE instructions.
+export function buildFilesReadContext(head: CompactionMessage[]): string | null {
+  const paths = deriveFilesRead(head);
+  if (paths.length === 0) return null;
+  return ['## Files Read', ...paths.map((p) => `- ${p}`)].join('\n');
+}
+
 // === prompt assembly ===
 
 // Build the final user message that asks the model to (re)produce the
@@ -220,15 +268,26 @@ export interface OpenAiMessage {
   tool_call_id?: string;
 }
 
-function isCapHitSentinel(m: CompactionMessage): boolean {
+// #12: mirror inference/sentinels.ts:isAnySentinel over the CompactionMessage
-  return m.role === 'system' && m.metadata != null && m.metadata.kind === 'cap_hit';
+// shape (which carries metadata as { kind?: string } | null, not the full
+// Message type isAnySentinel expects). All UI-only sentinels are stripped from
+// the head payload — they never go to the summarizer LLM. Keep the kind list in
+// sync with isAnySentinel in sentinels.ts.
+const SENTINEL_KINDS = new Set(['cap_hit', 'doom_loop', 'mistake_recovery']);
+function isAnySentinel(m: CompactionMessage): boolean {
+  return (
+    m.role === 'system' &&
+    m.metadata != null &&
+    typeof m.metadata.kind === 'string' &&
+    SENTINEL_KINDS.has(m.metadata.kind)
+  );
 }
 
 // v1.13.6: exported for unit-test access (reasoning render coverage).
 export function buildHeadPayload(head: CompactionMessage[]): OpenAiMessage[] {
   const out: OpenAiMessage[] = [];
   for (const m of head) {
-    if (isCapHitSentinel(m)) continue;
+    if (isAnySentinel(m)) continue;
     if (m.role === 'assistant' && (m.status === 'streaming' || m.status === 'cancelled')) continue;
     if (m.kind === 'compact') {
       // Legacy compact row — pass through as system context. The new
@@ -417,7 +476,14 @@ export async function process(input: ProcessInput): Promise<void> {
   // user message carrying buildPrompt(previousSummary, []). No system prompt
   // — matches opencode (`system: []`); the template + anchor are sufficient.
   const headPayload = buildHeadPayload(sel.head);
-  const finalUser: OpenAiMessage = { role: 'user', content: buildPrompt(previousSummary, []) };
+  // #12 Part B: derive the file-provenance ledger from the head's read-tool
+  // calls and inject it as a deterministic ## Files Read context block so the
+  // summarizer merges it into the rolling summary. Empty → no injection.
+  const filesReadCtx = buildFilesReadContext(sel.head);
+  const finalUser: OpenAiMessage = {
+    role: 'user',
+    content: buildPrompt(previousSummary, filesReadCtx ? [filesReadCtx] : []),
+  };
   const payload = [...headPayload, finalUser];
 
   log.info(

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

@@ -19,6 +19,14 @@ export type {
 } from './turn.js';
 export type { ToolPhaseResult } from './tool-phase.js';
 export { detectDoomLoop, DOOM_LOOP_THRESHOLD } from './sentinels.js';
+export {
+  detectMistakePattern,
+  freshMistakeState,
+  recordStep,
+  MISTAKE_THRESHOLD,
+  MISTAKE_RECOVERY_NOTE,
+} from './mistake-tracker.js';
+export type { FailureKind, MistakeState } from './mistake-tracker.js';
 export { buildMessagesPayload } from './payload.js';
 export { generateToolUseSummary } from './tool-summaries.js';
 export type { ToolInfo } from './tool-summaries.js';

apps/server/src/services/inference/mistake-tracker.ts

@@ -0,0 +1,69 @@
+// v#12 MistakeTracker: heterogeneous-failure recovery. Complements the
+// doom-loop guard (sentinels.ts:detectDoomLoop, which only catches *identical*
+// repeats) by catching a run of consecutive tool FAILURES the model isn't
+// recovering from — even when each failure is a *different* error. Algorithm
+// reimplemented from cline's mistake-counting pattern (NOT vendored).
+//
+// Pure module — mirrors sentinels.ts:detectDoomLoop. No DB, no I/O. The state
+// lives loop-local in TurnArgs (reset per runInference, like recentToolCalls).
+
+// The failure taxonomy already distinguished in tool-phase.ts:executeToolCall.
+// 'api_error' is reserved for upstream-model failures surfaced as tool outcomes
+// (no current emit site on apps/server, but the union mirrors the design doc
+// so a future caller can record it without a type change).
+export type FailureKind =
+  | 'zod_reject'
+  | 'tool_not_found'
+  | 'exec_error'
+  | 'api_error'
+  | 'permission_denied';
+
+// Smallest streak that doesn't false-positive on a model that retries once
+// after a transient error. Matches DOOM_LOOP_THRESHOLD's rationale.
+export const MISTAKE_THRESHOLD = 3;
+
+export interface MistakeState {
+  // The current consecutive-failure streak (any successful tool step clears it).
+  run: FailureKind[];
+  // How many recovery nudges have fired without an intervening success. Used to
+  // escalate (stop the turn) on the second trip rather than nudging forever.
+  nudges: number;
+}
+
+export function freshMistakeState(): MistakeState {
+  return { run: [], nudges: 0 };
+}
+
+// Record one tool step's outcome. A 'success' clears BOTH the streak and the
+// nudge counter (the model recovered). A FailureKind pushes onto the streak.
+export function recordStep(
+  state: MistakeState,
+  outcome: FailureKind | 'success',
+): void {
+  if (outcome === 'success') {
+    state.run = [];
+    state.nudges = 0;
+    return;
+  }
+  state.run.push(outcome);
+}
+
+// Decide whether to intervene given the current streak. When the streak has
+// reached MISTAKE_THRESHOLD: 'nudge' the first time (no nudge fired yet),
+// 'escalate' if it trips again while a nudge is already outstanding (no
+// intervening success cleared `nudges`). Below threshold → null.
+//
+// Pure — the caller is responsible for mutating `nudges`/`run` after acting on
+// the decision (mirrors how turn.ts consumes detectDoomLoop's result).
+export function detectMistakePattern(
+  state: MistakeState,
+): 'nudge' | 'escalate' | null {
+  if (state.run.length < MISTAKE_THRESHOLD) return null;
+  return state.nudges === 0 ? 'nudge' : 'escalate';
+}
+
+// Model-facing guidance injected (transiently, for the next step only) when a
+// nudge fires. Short + declarative for the same reliability reason as the
+// cap-hit / doom-loop notes.
+export const MISTAKE_RECOVERY_NOTE =
+  "You've hit several different errors in a row. Stop retrying variations — re-read the tool schemas, verify file paths and arguments exist before calling, and try a fundamentally different approach.";

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

@@ -717,3 +717,57 @@ async function insertDoomLoopSentinel(
     metadata,
   });
 }
+
+// #12 MistakeTracker: heterogeneous-failure recovery sentinel. Mirrors
+// insertDoomLoopSentinel structurally — a role='system', status='complete' row
+// firing the standard message_started → delta → message_complete frame
+// sequence. Two variants distinguished by `escalated`:
+//   - escalated:false → a nudge fired; recovery guidance was injected into the
+//     model's next step and the loop continued. can_continue is true (the turn
+//     is still live).
+//   - escalated:true  → the nudge didn't break the failure run; the turn was
+//     stopped (cap-hit-style). can_continue is true so the UI can still offer a
+//     Continue affordance — a fresh user turn resets the tracker.
+export async function insertMistakeRecoverySentinel(
+  ctx: InferenceContext,
+  sessionId: string,
+  chatId: string,
+  opts: { failureKinds: string[]; count: number; escalated: boolean; canContinue: boolean },
+): Promise<void> {
+  const metadata: MessageMetadata = {
+    kind: 'mistake_recovery',
+    failure_kinds: opts.failureKinds,
+    count: opts.count,
+    escalated: opts.escalated,
+    can_continue: opts.canContinue,
+  };
+  const content = opts.escalated
+    ? `Repeated different errors persisted after a recovery nudge (${opts.count} in a row). Stopping the tool-call loop.`
+    : `Hit ${opts.count} different errors in a row. Injected recovery guidance and continuing.`;
+
+  const [row] = await ctx.sql<{ id: string }[]>`
+    INSERT INTO messages (session_id, chat_id, role, content, status, created_at, metadata)
+    VALUES (${sessionId}, ${chatId}, 'system', ${content}, 'complete', clock_timestamp(), ${ctx.sql.json(metadata as never)})
+    RETURNING id
+  `;
+
+  // Standard frame sequence — same as cap-hit / doom-loop sentinels.
+  ctx.publish(sessionId, {
+    type: 'message_started',
+    message_id: row!.id,
+    chat_id: chatId,
+    role: 'system',
+  });
+  ctx.publish(sessionId, {
+    type: 'delta',
+    message_id: row!.id,
+    chat_id: chatId,
+    content,
+  });
+  ctx.publish(sessionId, {
+    type: 'message_complete',
+    message_id: row!.id,
+    chat_id: chatId,
+    metadata,
+  });
+}

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

@@ -48,6 +48,18 @@ export function isDoomLoopSentinel(m: Message): boolean {
   );
 }
 
-export function isAnySentinel(m: Message): boolean {
+// #12: mistake-recovery sentinel. Same UI-only semantics as cap-hit /
-  return isCapHitSentinel(m) || isDoomLoopSentinel(m);
+// doom-loop — never sent to the LLM (filtered via the isAnySentinel check
+// below, which buildMessagesPayload + buildHeadPayload both consult).
+export function isMistakeRecoverySentinel(m: Message): boolean {
+  return (
+    m.role === 'system' &&
+    m.metadata !== null &&
+    typeof m.metadata === 'object' &&
+    (m.metadata as { kind?: unknown }).kind === 'mistake_recovery'
+  );
+}
+
+export function isAnySentinel(m: Message): boolean {
+  return isCapHitSentinel(m) || isDoomLoopSentinel(m) || isMistakeRecoverySentinel(m);
 }

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

@@ -17,6 +17,7 @@ import { formatUnknownToolError } from './tool-suggestions.js';
 // prompted about paths we couldn't grant anyway (e.g. /etc/passwd).
 import { resolveGrantRoot } from '../grant_resolver.js';
 import { stripToolMarkup } from './tool-call-parser.js';
+import type { FailureKind } from './mistake-tracker.js';
 import type {
   InferenceContext,
   StreamResult,
@@ -33,13 +34,18 @@ async function executeToolCall(
   toolCall: ToolCall,
   extraRoots: readonly string[],
   toolCtx?: ToolExecCtx,
-): Promise<{ output: unknown; truncated: boolean; error?: string }> {
+): Promise<{ output: unknown; truncated: boolean; error?: string; outcome: FailureKind | 'success' }> {
+  // v#12 MistakeTracker: every return path carries an `outcome` so the turn
+  // loop can detect a run of heterogeneous failures. The failure taxonomy
+  // mirrors mistake-tracker.ts:FailureKind. Does NOT alter the existing
+  // output/truncated/error shape — outcome is purely additive.
   const tool = TOOLS_BY_NAME[toolCall.name];
   if (!tool) {
     return {
       output: null,
       truncated: false,
       error: formatUnknownToolError(toolCall.name, Object.keys(TOOLS_BY_NAME)),
+      outcome: 'tool_not_found',
     };
   }
   const parsed = tool.inputSchema.safeParse(toolCall.args);
@@ -64,6 +70,7 @@ async function executeToolCall(
       output: null,
       truncated: false,
       error: `tool '${toolCall.name}' rejected — ${hint}`,
+      outcome: 'zod_reject',
     };
   }
   try {
@@ -72,15 +79,16 @@ async function executeToolCall(
       typeof output === 'object' && output !== null && 'truncated' in output
         ? Boolean((output as { truncated: unknown }).truncated)
         : false;
-    return { output, truncated };
+    return { output, truncated, outcome: 'success' };
   } catch (err) {
     if (err instanceof PathScopeError) {
-      return { output: null, truncated: false, error: err.message };
+      return { output: null, truncated: false, error: err.message, outcome: 'permission_denied' };
     }
     return {
       output: null,
       truncated: false,
       error: err instanceof Error ? err.message : String(err),
+      outcome: 'exec_error',
     };
   }
 }
@@ -93,6 +101,12 @@ export interface ToolPhaseResult {
   toolCallCount: number;
   toolCalls: ToolCall[];
   nextAssistantId: string | null;
+  // v#12 MistakeTracker: one outcome per executed tool call, in no particular
+  // order (filled inside the Promise.all callbacks). The turn loop folds these
+  // into TurnArgs.mistakeTracker via recordStep. Pause/auto-grant control-flow
+  // tools record 'success' (they aren't model mistakes); the genuine error
+  // paths record their FailureKind.
+  outcomes: (FailureKind | 'success')[];
 }
 
 export async function executeToolPhase(
@@ -187,6 +201,10 @@ export async function executeToolPhase(
   // for the synthesis input. Race-free under Promise.all because each
   // callback pushes its own captured value.
   const synthEntries: Array<{ tc: ToolCall; output: unknown; error?: string }> = [];
+  // v#12 MistakeTracker: collect each tool's outcome. Concurrent pushes under
+  // Promise.all are safe (each callback appends its own value; order is not
+  // significant to recordStep which folds them sequentially).
+  const outcomes: (FailureKind | 'success')[] = [];
   await Promise.all(
     toolCalls.map(async (tc) => {
       const [toolRow] = await ctx.sql<{ id: string }[]>`
@@ -197,6 +215,7 @@ export async function executeToolPhase(
       const toolMessageId = toolRow!.id;
       if (tc.name === 'ask_user_input') {
         pausingForUserInput = true;
+        outcomes.push('success');
         const sentinel = { tool_call_id: tc.id, output: null, truncated: false };
         // v1.13.20: parts-only. The answer-endpoint UPDATE later
         // (messages.ts) will delete and re-insert this part when the user
@@ -227,7 +246,10 @@ export async function executeToolPhase(
         );
         if (!resolution.ok) {
           // Auto-deny without pausing. The model sees the reason on its
-          // next turn and decides what to do.
+          // next turn and decides what to do. Counts as a permission_denied
+          // failure for the mistake tracker (the model asked for a path it
+          // can't have — a recoverable mistake it should learn from).
+          outcomes.push('permission_denied');
           const stored = {
             tool_call_id: tc.id,
             output: `denied: ${resolution.reason}`,
@@ -255,6 +277,7 @@ export async function executeToolPhase(
         // pause. The grant endpoint re-derives the root at decision time
         // (state may have changed in the meantime) so we don't stash it here.
         pausingForUserInput = true;
+        outcomes.push('success');
         const sentinel = { tool_call_id: tc.id, output: null, truncated: false };
         // v1.13.20: parts-only write.
         await insertParts(
@@ -267,6 +290,10 @@ export async function executeToolPhase(
         return;
       }
       if (agent && !matchToolGlob(tc.name, agent.tools)) {
+        // Agent-scope denial — the model called a tool outside its whitelist.
+        // permission_denied for the mistake tracker (the model should pick a
+        // tool it's actually allowed to use).
+        outcomes.push('permission_denied');
         const stored = {
           tool_call_id: tc.id,
           output: null,
@@ -295,6 +322,10 @@ export async function executeToolPhase(
         sql: ctx.sql,
         sessionId,
       });
+      // v#12 MistakeTracker: record the real execution outcome (success or a
+      // FailureKind). This is the primary signal for heterogeneous-failure
+      // detection.
+      outcomes.push(tres.outcome);
       if (SYNTHESIS_TOOLS.has(tc.name)) {
         synthEntries.push({ tc, output: tres.output, ...(tres.error ? { error: tres.error } : {}) });
       }
@@ -340,6 +371,7 @@ export async function executeToolPhase(
       toolCallCount: toolCalls.length,
       toolCalls,
       nextAssistantId: null,
+      outcomes,
     };
   }
 
@@ -378,6 +410,7 @@ export async function executeToolPhase(
         toolCallCount: toolCalls.length,
         toolCalls,
         nextAssistantId: null,
+        outcomes,
       };
     }
     // ran === false → synthesis failed (timeout / model error) → fall through
@@ -397,5 +430,6 @@ export async function executeToolPhase(
     toolCallCount: toolCalls.length,
     toolCalls,
     nextAssistantId: nextAssistant!.id,
+    outcomes,
   };
 }

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

@@ -22,6 +22,13 @@ import { resolveToolBudget } from './budget.js';
 import {
   detectDoomLoop,
 } from './sentinels.js';
+import {
+  detectMistakePattern,
+  freshMistakeState,
+  recordStep,
+  MISTAKE_RECOVERY_NOTE,
+  type MistakeState,
+} from './mistake-tracker.js';
 import {
   buildMessagesPayload,
   loadContext,
@@ -39,6 +46,7 @@ import {
   runCapHitSummary,
   runDoomLoopSummary,
   runStepCapSummary,
+  insertMistakeRecoverySentinel,
 } from './sentinel-summaries.js';
 
 // v1.14.0: hard ceiling on the number of stream-and-tool iterations per
@@ -144,6 +152,16 @@ export interface TurnArgs {
   // boundaries by runInference, same as toolsUsed. Doom-loop check at the
   // top of runAssistantTurn slices the last DOOM_LOOP_THRESHOLD entries.
   recentToolCalls: ToolCall[];
+  // v#12 MistakeTracker: heterogeneous-failure recovery state. Loop-local,
+  // reset per runInference (user-message boundary) like recentToolCalls. Folds
+  // tool-phase outcomes via recordStep each iteration; detectMistakePattern
+  // gates the nudge/escalate decision.
+  mistakeTracker: MistakeState;
+  // v#12: transient model-facing recovery note set when a nudge fires. Consumed
+  // (appended as a role:'system' message + cleared) on the NEXT payload build.
+  // Never persisted — mirrors how the cap-hit/doom-loop notes live only inside
+  // the summary call's messages array.
+  pendingRecoveryNote?: string;
   signal: AbortSignal | undefined;
 }
 
@@ -188,6 +206,12 @@ export async function runAssistantTurn(
   let toolsUsed = args.toolsUsed;
   let recentToolCalls = args.recentToolCalls;
   let assistantMessageId = args.assistantMessageId;
+  // v#12 MistakeTracker: the tracker state is carried on `args` (mutated in
+  // place by recordStep). pendingRecoveryNote is a loop-local because it is a
+  // single-step transient — set when a nudge fires, consumed (injected into the
+  // next payload) and cleared on the following iteration.
+  const mistakeTracker = args.mistakeTracker;
+  let pendingRecoveryNote: string | undefined = args.pendingRecoveryNote;
 
   while (stepNumber < effectiveCap) {
     // ---- doom-loop check (moved from top-of-function) ----
@@ -196,7 +220,7 @@ export async function runAssistantTurn(
       // Need fresh history for the summary.
       const loaded = await loadContext(ctx.sql, sessionId, chatId);
       if (loaded) {
-        const iterArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, signal };
+        const iterArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, mistakeTracker, signal };
         await runDoomLoopSummary(ctx, iterArgs, loaded.session, loaded.project, loaded.history, agent, loop);
       }
       break;
@@ -206,7 +230,7 @@ export async function runAssistantTurn(
     if (toolsUsed >= budget) {
       const loaded = await loadContext(ctx.sql, sessionId, chatId);
       if (loaded) {
-        const iterArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, signal };
+        const iterArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, mistakeTracker, signal };
         await runCapHitSummary(ctx, iterArgs, loaded.session, loaded.project, loaded.history, agent, budget);
       }
       break;
@@ -265,7 +289,16 @@ export async function runAssistantTurn(
       }
     }
 
-    const iterArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, signal };
+    // v#12 MistakeTracker: if the prior iteration's nudge fired, append the
+    // transient recovery note to THIS payload (consumed exactly once, then
+    // cleared). Never persisted — same lifecycle as the cap-hit/doom-loop
+    // summary notes, which live only inside the in-memory messages array.
+    if (pendingRecoveryNote) {
+      messages.push({ role: 'system', content: pendingRecoveryNote });
+      pendingRecoveryNote = undefined;
+    }
+
+    const iterArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, mistakeTracker, signal };
     const state: StreamPhaseState = { accumulated: '', startedAt: null };
     let result: StreamResult;
     try {
@@ -305,10 +338,78 @@ export async function runAssistantTurn(
     recentToolCalls = [...recentToolCalls, ...toolPhaseResult.toolCalls];
     stepNumber++;
 
+    // v#12 MistakeTracker: fold this iteration's tool outcomes into the
+    // tracker, in order. recordStep mutates `mistakeTracker` in place (it is
+    // the same object referenced by args). A 'success' clears the streak.
+    for (const o of toolPhaseResult.outcomes) {
+      recordStep(mistakeTracker, o);
+    }
+
     if (toolPhaseResult.action !== 'continue') {
-      // 'paused' (user input) or 'synthesis_done' — stop the loop.
+      // 'paused' (user input) or 'synthesis_done' — stop the loop. The turn is
+      // already ending, so neither a nudge nor an escalate would change the
+      // control flow; we skip the mistake decision here.
       break;
     }
+
+    // v#12 MistakeTracker: heterogeneous-failure decision. Only evaluated on
+    // the 'continue' path (the only case where the loop would otherwise
+    // proceed to another step). Complements the doom-loop check above, which
+    // only catches *identical* repeats.
+    const mistake = detectMistakePattern(mistakeTracker);
+    if (mistake === 'nudge') {
+      // Soft intervention: inject model-facing recovery guidance into the NEXT
+      // step's payload, drop a UI sentinel, bump nudges, reset the streak, and
+      // continue. The note is consumed (and cleared) at the top of the next
+      // iteration's payload build.
+      pendingRecoveryNote = MISTAKE_RECOVERY_NOTE;
+      const failureKinds = [...mistakeTracker.run];
+      await insertMistakeRecoverySentinel(ctx, sessionId, chatId, {
+        failureKinds,
+        count: failureKinds.length,
+        escalated: false,
+        canContinue: true,
+      });
+      mistakeTracker.nudges += 1;
+      mistakeTracker.run = [];
+      ctx.log.info(
+        { sessionId, chatId, step: stepNumber, nudges: mistakeTracker.nudges, failureKinds },
+        'mistake_recovery nudge',
+      );
+      assistantMessageId = toolPhaseResult.nextAssistantId!;
+      continue;
+    }
+    if (mistake === 'escalate') {
+      // The nudge didn't break the failure run — stop the turn (cap-hit-style)
+      // to avoid burning the whole step budget on heterogeneous failures. The
+      // next assistant row is still 'streaming'; finalize it as a short note so
+      // the slot doesn't dangle, then drop the escalate sentinel.
+      const failureKinds = [...mistakeTracker.run];
+      assistantMessageId = toolPhaseResult.nextAssistantId!;
+      await ctx.sql`
+        UPDATE messages
+        SET content = '', status = 'complete', finished_at = clock_timestamp()
+        WHERE id = ${assistantMessageId}
+      `;
+      ctx.publish(sessionId, {
+        type: 'message_complete',
+        message_id: assistantMessageId,
+        chat_id: chatId,
+      });
+      await insertMistakeRecoverySentinel(ctx, sessionId, chatId, {
+        failureKinds,
+        count: failureKinds.length,
+        escalated: true,
+        canContinue: true,
+      });
+      ctx.publishUser({ type: 'chat_status', chat_id: chatId, status: 'idle', at: new Date().toISOString() });
+      ctx.log.info(
+        { sessionId, chatId, step: stepNumber, failureKinds },
+        'mistake_recovery escalate — stopping turn',
+      );
+      break;
+    }
+
     // 'continue' — advance to next assistant message.
     assistantMessageId = toolPhaseResult.nextAssistantId!;
   }
@@ -320,7 +421,7 @@ export async function runAssistantTurn(
   if (stepNumber >= effectiveCap && effectiveCap < Infinity) {
     const loaded = await loadContext(ctx.sql, sessionId, chatId);
     if (loaded) {
-      const capArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, signal };
+      const capArgs: TurnArgs = { sessionId, chatId, assistantMessageId, toolsUsed, recentToolCalls, mistakeTracker, signal };
       await runStepCapSummary(ctx, capArgs, loaded.session, loaded.project, loaded.history, agent, stepNumber, effectiveCap);
     }
   }
@@ -378,12 +479,16 @@ export async function runInference(
   // per-call budget.
   // v1.11.6: recentToolCalls also resets — doom-loop detection is scoped
   // to a single user-message turn, so a Continue starts with no history.
+  // v#12 MistakeTracker: fresh per user-message turn, like recentToolCalls.
+  // Tracks consecutive heterogeneous tool failures across the loop's
+  // stream-and-tool iterations within this turn.
   return runAssistantTurn(ctx, {
     sessionId,
     chatId,
     assistantMessageId,
     toolsUsed: 0,
     recentToolCalls: [],
+    mistakeTracker: freshMistakeState(),
     signal,
   });
 }

apps/server/src/types/api.ts

@@ -207,10 +207,15 @@ export type ErrorReason =
   | 'summary_after_cap_failed';
 
 // v1.8.2 / v1.11.6: shapes stored in messages.metadata. Discriminated on `kind`.
-//   cap_hit    — system sentinel emitted when tool budget is exhausted
+//   cap_hit          — system sentinel emitted when tool budget is exhausted
-//   doom_loop  — system sentinel emitted when the model called the same
+//   doom_loop        — system sentinel emitted when the model called the same
-//                tool with the same args DOOM_LOOP_THRESHOLD times in a row
+//                      tool with the same args DOOM_LOOP_THRESHOLD times in a row
-//   error      — attached to a failed assistant message so UI can show reason
+//   mistake_recovery — system sentinel emitted when a run of consecutive
+//                      *heterogeneous* tool failures is detected (#12). A nudge
+//                      (escalated:false) injects model-facing recovery guidance
+//                      and continues; an escalate (escalated:true) stops the
+//                      turn after the nudge failed to break the failure run.
+//   error            — attached to a failed assistant message so UI can show reason
 export type MessageMetadata =
   | {
       kind: 'cap_hit';
@@ -225,6 +230,14 @@ export type MessageMetadata =
       args: Record<string, unknown>;
       threshold: number;
     }
+  | {
+      // PINNED CONTRACT (#12) — mirrored byte-for-byte in apps/web/src/api/types.ts.
+      kind: 'mistake_recovery';
+      failure_kinds: string[];
+      count: number;
+      escalated: boolean;
+      can_continue?: boolean;
+    }
   | {
       kind: 'error';
       error_reason: ErrorReason;

apps/server/src/types/ws-frames.ts

@@ -39,6 +39,12 @@ const ChatStatusValue = z.enum([
   'error',
 ]);
 
+// agent-status-normalize (#10): normalized per-(chat,agent) lifecycle status for
+// external coding agents (warm-acp / opencode / claude-sdk / pty). Distinct from
+// ChatStatusValue (native-inference chat lifecycle) — published by BooCoder's
+// dispatcher + permission flow on the per-session channel.
+const AgentStatusValue = z.enum(['working', 'blocked', 'idle', 'error']);
+
 const ErrorReasonValue = z.enum([
   'llm_provider_error',
   'doom_loop',
@@ -301,6 +307,21 @@ export const AgentCommandsFrame = z.object({
   commands: z.array(AgentCommandShape),
 });
 
+// agent-status-normalize (#10): published by BooCoder on the per-session channel
+// when an external agent's normalized status changes (turn start/end, permission
+// block/unblock). Keyed per (chat_id, agent); the frontend tracks the latest per
+// pair and resets on chat switch. `reason` is a free-form discriminator
+// (turn_start / turn_complete / failed / crashed / permission_request /
+// permission_resolved).
+export const AgentStatusUpdatedFrame = z.object({
+  type: z.literal('agent_status_updated'),
+  chat_id: Uuid,
+  agent: z.string().min(1),
+  status: AgentStatusValue,
+  reason: z.string().optional(),
+  at: IsoTimestamp,
+});
+
 // ---- discriminated union ---------------------------------------------------
 
 export const WsFrameSchema = z.discriminatedUnion('type', [
@@ -320,6 +341,7 @@ export const WsFrameSchema = z.discriminatedUnion('type', [
   PermissionRequestedFrame,
   PermissionResolvedFrame,
   AgentCommandsFrame,
+  AgentStatusUpdatedFrame,
   // per-user
   ChatStatusFrame,
   SessionUpdatedFrame,
@@ -361,6 +383,7 @@ export const KNOWN_FRAME_TYPES: readonly WsFrame['type'][] = [
   'permission_requested',
   'permission_resolved',
   'agent_commands',
+  'agent_status_updated',
   'chat_status',
   'session_updated',
   'session_renamed',

apps/web/src/api/types.ts

@@ -155,6 +155,9 @@ export type ErrorReason =
 //                budget + agent name + whether Continue is still allowed.
 //   doom_loop  — sentinel emitted when the model called the same tool with
 //                the same arguments threshold times in a row.
+//   mistake_recovery — sentinel emitted when the model hit repeated *different*
+//                errors; non-escalated means recovery guidance was injected and
+//                the turn continues, escalated means the turn was stopped.
 //   error      — attached to a failed assistant message so the bubble can show
 //                a specific reason on reload (WS error frame is one-shot).
 export type MessageMetadata =
@@ -171,6 +174,13 @@ export type MessageMetadata =
       args: Record<string, unknown>;
       threshold: number;
     }
+  | {
+      kind: 'mistake_recovery';
+      failure_kinds: string[];
+      count: number;
+      escalated: boolean;
+      can_continue?: boolean;
+    }
   | {
       kind: 'error';
       error_reason: ErrorReason;
@@ -586,4 +596,16 @@ export type WsFrame =
   | { type: 'compacted'; session_id: string; chat_id: string; summary_message_id: string }
   // v1.8.2: `reason` discriminates structured failures (the UI prefers it
   // over `error` text when present).
-  | { type: 'error'; message_id?: string; chat_id?: string; error: string; reason?: ErrorReason };
+  | { type: 'error'; message_id?: string; chat_id?: string; error: string; reason?: ErrorReason }
+  // agent-status-normalize (#10): BooCoder publishes a normalized per-(chat,agent)
+  // lifecycle status for external coding agents on the per-session channel. The
+  // CoderPane tracks the latest status per (chat_id, agent) and resets on chat
+  // switch; AgentComposerBar renders the dot (distinct from the WS-liveness dot).
+  | {
+      type: 'agent_status_updated';
+      chat_id: string;
+      agent: string;
+      status: 'working' | 'blocked' | 'idle' | 'error';
+      reason?: string;
+      at: string;
+    };

apps/web/src/api/ws-frames.ts

@@ -39,6 +39,12 @@ const ChatStatusValue = z.enum([
   'error',
 ]);
 
+// agent-status-normalize (#10): normalized per-(chat,agent) lifecycle status for
+// external coding agents (warm-acp / opencode / claude-sdk / pty). Distinct from
+// ChatStatusValue (native-inference chat lifecycle) — published by BooCoder's
+// dispatcher + permission flow on the per-session channel.
+const AgentStatusValue = z.enum(['working', 'blocked', 'idle', 'error']);
+
 const ErrorReasonValue = z.enum([
   'llm_provider_error',
   'doom_loop',
@@ -301,6 +307,21 @@ export const AgentCommandsFrame = z.object({
   commands: z.array(AgentCommandShape),
 });
 
+// agent-status-normalize (#10): published by BooCoder on the per-session channel
+// when an external agent's normalized status changes (turn start/end, permission
+// block/unblock). Keyed per (chat_id, agent); the frontend tracks the latest per
+// pair and resets on chat switch. `reason` is a free-form discriminator
+// (turn_start / turn_complete / failed / crashed / permission_request /
+// permission_resolved).
+export const AgentStatusUpdatedFrame = z.object({
+  type: z.literal('agent_status_updated'),
+  chat_id: Uuid,
+  agent: z.string().min(1),
+  status: AgentStatusValue,
+  reason: z.string().optional(),
+  at: IsoTimestamp,
+});
+
 // ---- discriminated union ---------------------------------------------------
 
 export const WsFrameSchema = z.discriminatedUnion('type', [
@@ -320,6 +341,7 @@ export const WsFrameSchema = z.discriminatedUnion('type', [
   PermissionRequestedFrame,
   PermissionResolvedFrame,
   AgentCommandsFrame,
+  AgentStatusUpdatedFrame,
   // per-user
   ChatStatusFrame,
   SessionUpdatedFrame,
@@ -361,6 +383,7 @@ export const KNOWN_FRAME_TYPES: readonly WsFrame['type'][] = [
   'permission_requested',
   'permission_resolved',
   'agent_commands',
+  'agent_status_updated',
   'chat_status',
   'session_updated',
   'session_renamed',

apps/web/src/components/AgentComposerBar.tsx

@@ -3,6 +3,7 @@ import { Check, ChevronDown, RefreshCw, Loader2, Shield, Brain, Bot } from 'luci
 import { api } from '@/api/client';
 import type { AgentSessionConfig, ProviderSnapshotEntry, AgentCommand } from '@/api/types';
 import { useProviderSnapshot, refreshProviderSnapshot } from '@/hooks/useProviderSnapshot';
+import type { AgentStatusEntry } from '@/hooks/useAgentStatus';
 import { providerIcon } from '@/components/coder/providerIcons';
 import { useAgentSessions } from '@/hooks/useAgentSessions';
 import {
@@ -183,6 +184,11 @@ interface Props {
   // True once the chat has at least one prior turn — gates the chip so it stays
   // hidden on a brand-new chat. Defaults to false (no chip).
   hasPriorTurn?: boolean;
+  // #10: normalized status (working|blocked|idle|error) for the active external
+  // agent in this chat, or null for native boocode / before any frame. Renders
+  // a status dot DISTINCT from the WS-liveness `connected` dot. Undefined for
+  // non-coder callers — no dot.
+  agentStatus?: AgentStatusEntry | null;
 }
 
 // Condensed token count: 950 → "950", 12_400 → "12.4K", 3_200_000 → "3.2M".
@@ -210,7 +216,42 @@ function relativeTime(iso: string | null): string {
   return `${day}d ago`;
 }
 
-export function AgentComposerBar({ projectPath, value, onChange, onProviderCommandsChange, connected, sessionId, hasPriorTurn }: Props) {
+// #10: normalized external-agent status dot. Mirrors StatusDot's visual
+// language but on the four normalized buckets (working|blocked|idle|error),
+// and is DISTINCT from the WS-liveness `connected` dot beside it:
+//   working — emerald spinning ring (subtle motion, like chat streaming)
+//   blocked — amber dot (matches the permission/blocked state colour)
+//   idle    — gray dot
+//   error   — red dot
+function AgentStatusDot({ entry, agent }: { entry: AgentStatusEntry; agent: string }) {
+  const title =
+    `${agent}: ${entry.status}` + (entry.reason ? ` — ${entry.reason}` : '');
+
+  if (entry.status === 'working') {
+    return (
+      <span
+        aria-label={`Agent status: working${entry.reason ? ` — ${entry.reason}` : ''}`}
+        title={title}
+        className="inline-block w-3 h-3 rounded-full border-2 border-emerald-500 border-t-transparent animate-spin shrink-0"
+      />
+    );
+  }
+
+  const bg =
+    entry.status === 'blocked' ? 'bg-amber-500'
+      : entry.status === 'error' ? 'bg-destructive'
+      : 'bg-muted-foreground/40';
+
+  return (
+    <span
+      aria-label={`Agent status: ${entry.status}${entry.reason ? ` — ${entry.reason}` : ''}`}
+      title={title}
+      className={cn('inline-block w-1.5 h-1.5 rounded-full shrink-0', bg)}
+    />
+  );
+}
+
+export function AgentComposerBar({ projectPath, value, onChange, onProviderCommandsChange, connected, sessionId, hasPriorTurn, agentStatus }: Props) {
   const allEntries = useProviderSnapshot(projectPath);
   // 5.5 — the composer picker only offers ENABLED providers that are ready (or
   // still loading). Disabled (enabled:false) and unavailable/error providers are
@@ -434,6 +475,11 @@ export function AgentComposerBar({ projectPath, value, onChange, onProviderComma
       {/* Status dot + refresh as one right-aligned unit so the refresh button
           stays on the top line instead of wrapping past the edge-pinned dot. */}
       <div className="ml-auto flex items-center gap-1 shrink-0">
+        {/* #10: normalized agent status — only for an external agent with a
+            live status frame. Distinct from the WS-liveness dot that follows. */}
+        {agentStatus && value.provider !== 'boocode' && (
+          <AgentStatusDot entry={agentStatus} agent={value.provider} />
+        )}
         {connected !== undefined && (
           <span
             className={cn('inline-block w-1.5 h-1.5 rounded-full shrink-0', connected ? 'bg-green-500' : 'bg-red-500')}

apps/web/src/components/MessageBubble.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useState } from 'react';
 import type { ReactNode } from 'react';
-import { ChevronDown, ChevronRight, Copy, RefreshCw, Check, Share2, RotateCw, GitFork, Trash2, Brain, History } from 'lucide-react';
+import { ChevronDown, ChevronRight, Copy, RefreshCw, Check, Share2, RotateCw, GitFork, Trash2, Brain, History, AlertCircle } from 'lucide-react';
 import { toast } from 'sonner';
 import type { Chat, ErrorReason, Message } from '@/api/types';
 import { api } from '@/api/client';
@@ -637,6 +637,76 @@ function ReasoningBlock({ text, streaming }: { text: string; streaming: boolean
   );
 }
 
+// feature #12: mistake-recovery sentinel. Inserted by the backend as a
+// role='system', metadata.kind='mistake_recovery' row when the model hit
+// repeated *different* errors (distinct from doom_loop, which is the same
+// call repeated). Visual treatment mirrors CapHitSentinel / DoomLoopSentinel
+// (amber card + alert icon). Non-escalated → recovery guidance was injected
+// and the turn continues. Escalated → the turn was stopped; if can_continue
+// is set, offer the same Continue affordance as the cap-hit sentinel.
+// Loose `!= null` guards per the CLAUDE.md coder-message note (coder rows pass
+// metadata as undefined, not null).
+function MistakeRecoverySentinel({ message }: { message: Message }) {
+  const meta = message.metadata;
+  const isMistakeRecovery =
+    meta != null && typeof meta === 'object' && meta.kind === 'mistake_recovery';
+  const failureKinds = isMistakeRecovery ? meta.failure_kinds : [];
+  const escalated = isMistakeRecovery ? meta.escalated : false;
+  const canContinue = isMistakeRecovery ? meta.can_continue === true : false;
+
+  const [continuing, setContinuing] = useState(false);
+
+  async function handleContinue() {
+    if (continuing || !canContinue) return;
+    setContinuing(true);
+    try {
+      await api.chats.continue(message.chat_id, message.id);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : 'continue failed');
+    } finally {
+      setContinuing(false);
+    }
+  }
+
+  const kindsLabel =
+    Array.isArray(failureKinds) && failureKinds.length > 0
+      ? failureKinds.join(', ')
+      : null;
+
+  return (
+    <div className="rounded-md border border-amber-500/40 bg-amber-500/10 text-sm">
+      <div className="px-3 py-2 flex items-start gap-2">
+        <AlertCircle className="size-4 text-amber-500 shrink-0 mt-0.5" />
+        <div className="flex-1 min-w-0 space-y-1">
+          <div className="text-xs font-medium text-amber-700 dark:text-amber-300">
+            {escalated ? 'Repeated errors — turn stopped' : 'Recovering from repeated errors'}
+          </div>
+          <div className="text-xs text-muted-foreground">
+            {escalated
+              ? 'Repeated errors persisted — stopped the turn.'
+              : kindsLabel
+                ? `Hit repeated different errors (${kindsLabel}) — recovery guidance injected, continuing.`
+                : 'Hit repeated different errors — recovery guidance injected, continuing.'}
+          </div>
+          {escalated && canContinue && (
+            <div className="pt-1">
+              <Button
+                type="button"
+                size="sm"
+                variant="outline"
+                onClick={() => void handleContinue()}
+                disabled={continuing}
+              >
+                {continuing ? 'Continuing…' : 'Continue'}
+              </Button>
+            </div>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+}
+
 export function MessageBubble({
   message,
   sessionChats,
@@ -681,6 +751,13 @@ export function MessageBubble({
     return <DoomLoopSentinel message={message} />;
   }
 
+  // feature #12: mistake-recovery sentinel. Non-escalated rows narrate that
+  // recovery guidance was injected mid-turn; escalated rows report the turn
+  // was stopped and (when can_continue) offer the cap-hit-style Continue.
+  if (message.role === 'system' && message.metadata?.kind === 'mistake_recovery') {
+    return <MistakeRecoverySentinel message={message} />;
+  }
+
   // v1.8.2: tool messages and assistant tool_calls are now rendered by
   // MessageList via ToolCallLine / ToolCallGroup. Tool-role messages reach
   // this point only if MessageList didn't consume them (shouldn't happen,

apps/web/src/components/panes/CoderPane.tsx

@@ -18,6 +18,7 @@ import { mergeWireToolCall } from '@/lib/coder-tools';
 import { CoderMessageList, type CoderTimelineWire } from '@/components/panes/CoderMessageList';
 import { providerIcon, providerLabel } from '@/components/coder/providerIcons';
 import { refreshAgentSessions } from '@/hooks/useAgentSessions';
+import { useAgentStatus, type AgentStatus, type AgentStatusEntry } from '@/hooks/useAgentStatus';
 import { cn } from '@/lib/utils';
 
 // ---------------------------------------------------------------------------
@@ -80,6 +81,14 @@ interface WsHandlers {
   onAssistantComplete?: () => void;
   onAgentCommands?: (taskId: string, commands: AgentCommand[]) => void;
   onConnectedChange?: (connected: boolean) => void;
+  // #10: normalized external-agent status (working|blocked|idle|error) for the
+  // (chat,agent) carried on the frame. CoderPane records it in a live map and
+  // feeds the active agent's status to AgentComposerBar's status dot.
+  onAgentStatus?: (
+    chatId: string,
+    agent: string,
+    entry: AgentStatusEntry,
+  ) => void;
 }
 
 type RawCoderMessage = {
@@ -326,6 +335,19 @@ function useCoderMessages(sessionId: string, chatId: string | undefined, handler
               description: c.description,
             })),
           );
+        } else if (frame.type === 'agent_status_updated') {
+          // #10: { chat_id, agent, status, reason?, at }. The chat_id guard
+          // above already dropped cross-chat frames; record per (chat,agent).
+          const chatId = (frame.chat_id ?? scopedChatId) as string | undefined;
+          const agent = frame.agent as string | undefined;
+          const status = frame.status as AgentStatus | undefined;
+          if (chatId && agent && status) {
+            handlersRef.current.onAgentStatus?.(chatId, agent, {
+              status,
+              ...(frame.reason ? { reason: frame.reason as string } : {}),
+              at: (frame.at as string) ?? new Date().toISOString(),
+            });
+          }
         }
       } catch {
         // ignore unparseable frames
@@ -642,6 +664,8 @@ export function CoderPane({
     return groups;
   }, [agentCommands, skillItems, agentConfig.provider]);
 
+  // #10: live normalized status per (chat,agent), reset on chat switch below.
+  const agentStatus = useAgentStatus();
   const { messages, setMessages, connected, loadMessages } = useCoderMessages(sessionId, chatId, {
     onConnectedChange,
     onPermissionRequested: (prompt) => {
@@ -661,7 +685,21 @@ export function CoderPane({
     onAgentCommands: (_taskId, commands) => {
       setLiveTaskCommands(commands);
     },
+    onAgentStatus: agentStatus.record,
   });
+
+  // Clear any stale status for the previous chat when the pane switches chats so
+  // a lingering working/blocked dot never carries into the next conversation.
+  useEffect(() => {
+    return () => agentStatus.reset(chatId);
+  }, [chatId, agentStatus]);
+
+  // The active agent's normalized status for this chat. null for native boocode
+  // (no external status published) or before any frame arrives — gates the dot.
+  const currentAgentStatus: AgentStatusEntry | null =
+    agentConfig.provider && agentConfig.provider !== 'boocode'
+      ? agentStatus.get(chatId, agentConfig.provider)
+      : null;
   const { changes, loading, refresh, approve, reject } = usePendingChanges(sessionId);
   const { checkpointMessageIds, refreshCheckpoints } = useCheckpoints(sessionId, chatId);
   const [input, setInput] = useState('');
@@ -968,6 +1006,7 @@ export function CoderPane({
         connected={connected}
         sessionId={sessionId}
         hasPriorTurn={hasPriorTurn}
+        agentStatus={currentAgentStatus}
       />
       {/* Chat area — BooChat-style timeline (text + tool runs as siblings) */}
       <div className="flex-1 min-h-0 flex flex-col">

apps/web/src/hooks/useAgentStatus.ts

@@ -0,0 +1,62 @@
+import { useCallback, useMemo, useState } from 'react';
+
+// Normalized external-agent status (#10). Consumed from the
+// `agent_status_updated` WS frame the coder backend publishes:
+//   { type: 'agent_status_updated'; chat_id; agent; status; reason?; at }
+// BooCoder collapses ~30 vendor lifecycle events into these four buckets:
+//   working  — turn in flight
+//   blocked  — waiting on a permission / approval
+//   idle     — clean completion
+//   error    — crash / failure
+export type AgentStatus = 'working' | 'blocked' | 'idle' | 'error';
+
+export interface AgentStatusEntry {
+  status: AgentStatus;
+  reason?: string;
+  at: string;
+}
+
+const key = (chatId: string, agent: string): string => `${chatId}:${agent}`;
+
+// Per-(chat,agent) live status map. The dot reflects the latest frame for the
+// active agent in the current chat; entries are reset when the chat switches so
+// a stale "working"/"blocked" from a previous chat never leaks into the next.
+export function useAgentStatus() {
+  const [map, setMap] = useState<Record<string, AgentStatusEntry>>({});
+
+  const record = useCallback(
+    (chatId: string, agent: string, entry: AgentStatusEntry) => {
+      setMap((prev) => ({ ...prev, [key(chatId, agent)]: entry }));
+    },
+    [],
+  );
+
+  // Drop every entry for a chat (called on chat switch). No-op when nothing
+  // matches so it's safe to call unconditionally from an effect.
+  const reset = useCallback((chatId: string | undefined) => {
+    setMap((prev) => {
+      if (!chatId) return prev;
+      const prefix = `${chatId}:`;
+      let changed = false;
+      const next: Record<string, AgentStatusEntry> = {};
+      for (const [k, v] of Object.entries(prev)) {
+        if (k.startsWith(prefix)) {
+          changed = true;
+          continue;
+        }
+        next[k] = v;
+      }
+      return changed ? next : prev;
+    });
+  }, []);
+
+  const get = useCallback(
+    (chatId: string | undefined, agent: string | undefined): AgentStatusEntry | null => {
+      if (!chatId || !agent) return null;
+      return map[key(chatId, agent)] ?? null;
+    },
+    [map],
+  );
+
+  return useMemo(() => ({ record, reset, get }), [record, reset, get]);
+}

apps/web/src/hooks/useSessionStream.ts

@@ -189,6 +189,12 @@ function applyFrame(state: State, frame: WsFrame): State {
       // duplicating async work inside a synchronous reducer.
       return state;
     }
+    case 'agent_status_updated': {
+      // agent-status-normalize (#10): coder-only frame consumed by CoderPane's
+      // own WS handler, not BooChat's native message reducer. No-op here to keep
+      // TS exhaustiveness satisfied (native sessions never emit it).
+      return state;
+    }
   }
 }
 

openspec/changes/agent-status-normalize/proposal.md

@@ -0,0 +1,61 @@
+# Normalized external-agent status (#10, scoped)
+
+**Status:** in progress (started 2026-06-01)
+**Source:** `boocode_code_review_v2.md` §1 #10, §5j (superset, Elastic License 2.0 — PATTERN-ONLY,
+clean-room; `/opt/forks/superset/.../map-event-type.ts`, `notify-hook.template.sh`, `agent-setup/*`).
+**Decision (Sam, 2026-06-01):** scoped status-publish now; config-injection notify-hook as a follow-on.
+
+## Why (corrected premise)
+BooCoder already *observes* agent lifecycle (warm-acp/opencode/SDK backends know active/idle/crashed;
+the permission-waiter knows blocked) but never **publishes a normalized per-`(chat,agent)` status** to the
+UI — so blocked-on-permission is invisible and crash/idle aren't pushed proactively. The `AgentComposerBar`
+dot only shows WS liveness. This batch publishes the status BooCoder already knows; the heavier
+config-injection notify-hook (for out-of-band signals) is the documented follow-on.
+
+## State model (clean-room from superset's `mapEventType`)
+Superset collapses ~30 vendor event names → 3 signals: **Start** (working), **PermissionRequest**
+(blocked), **Stop** (done). BooCoder adds idle (after done) + error (crash/fail). Normalized status:
+`working | blocked | idle | error`.
+
+## Pinned frame contract (server + web, byte-identical, parity-tested)
+```ts
+{ type: 'agent_status_updated', chat_id: Uuid, agent: string,
+  status: 'working' | 'blocked' | 'idle' | 'error', reason?: string, at: IsoTimestamp }
+```
+Added to `apps/server/src/types/ws-frames.ts` AND `apps/web/src/api/ws-frames.ts` (the `ws-frames` parity
+test), plus the web `WsFrame` union in `apps/web/src/api/types.ts`. Published via the coder's
+`broker.publishFrame` (validated against the server `WsFrameSchema`).
+
+## Clean-room normalize helper (built now, reused by the injection follow-on)
+`apps/coder/src/services/normalize-agent-status.ts`:
+`normalizeAgentEvent(raw: string): 'working' | 'blocked' | 'done' | null` — a clean-room reimplementation
+of the vendor-event-name → bucket mapping (the event names are facts about each agent's hooks:
+`SessionStart`/`UserPromptSubmit`/`PostToolUse`→working; `PreToolUse`/`Notification`/`PermissionRequest`/
+`exec_approval_request`→blocked; `Stop`/`session_end`/`task_complete`→done). The scoped publish points use
+BooCoder's own already-normalized turn boundaries; this helper exists so the config-injection follow-on
+(which receives raw vendor event names POSTed from agent hooks) reuses it. Unit-tested.
+
+## Publish points (BooCoder's existing observation — no per-backend change)
+- Dispatcher (`dispatcher.ts`) turn boundaries, for every external-agent path (warm-acp/opencode/sdk/pty):
+  `working` at turn start, `idle` on clean completion, `error` on failure.
+- Permission-waiter (`permission-waiter.ts` / the `setPermissionHooks` publish in `index.ts`): `blocked`
+  when a permission is requested, back to `working` when resolved.
+A small `publishAgentStatus(broker, chatId, agent, status, reason?)` helper centralizes the frame.
+
+## Frontend
+- `CoderPane.tsx` tracks the latest `agent_status_updated` per `(chat, agent)` (a small live map; reset on
+  chat switch).
+- `AgentComposerBar.tsx` renders a normalized status dot beside the existing session chip (reuse the
+  `StatusDot` visual language: working=spinner/green, blocked=amber, idle=gray, error=red), distinct from
+  the WS-liveness `connected` dot.
+
+## Follow-on (documented, not built): config-injection notify-hook
+Clean-room re-derive superset's `agent-setup`: inject a notify hook into each agent's native config
+(claude `~/.claude/settings.json`, opencode plugin, codex/gemini templates) that POSTs
+`{agent, chat_id, eventType}` to a new `POST /api/coder/agent-status` endpoint, which runs
+`normalizeAgentEvent` → publishes the SAME `agent_status_updated` frame. Reuses everything this batch
+builds. Catches out-of-band signals BooCoder's dispatch can't see.
+
+## Verify
+- `pnpm -C apps/coder test` (+ normalize-agent-status tests) + `pnpm -C apps/server test` (ws-frames parity)
+- `pnpm -C apps/server build && pnpm -C apps/coder build`; `npx tsc -p apps/web/tsconfig.app.json --noEmit`

openspec/changes/claude-sdk-sessionstore/proposal.md

@@ -0,0 +1,68 @@
+# Claude Agent SDK backend + clean-room PostgresSessionStore (#9)
+
+**Status:** in progress (started 2026-06-01)
+**Source:** `boocode_code_review_v2.md` §1 #9, §5h/§5i (happy + SDK `.d.ts`). Decision §6.2: lean SDK.
+**SDK:** `@anthropic-ai/claude-agent-sdk@0.3.159` (installed, Commercial Terms — runtime dep OK, code
+reference-only; the store is **clean-room** from the real interface, not vendored).
+
+Replace BooCoder's one-shot PTY claude dispatch with a warm, resumable Claude-SDK backend. Two parts:
+the clean-room session store (fully testable here) and the backend + wiring (live pump needs a host
+smoke against real `claude`).
+
+## Ground-truth SDK API (from the installed `sdk.d.ts`)
+- `query({ prompt: string | AsyncIterable<SDKUserMessage>, options?: Options }): Query` where
+  `Query extends AsyncGenerator<SDKMessage, void>`.
+- `Options`: `sessionStore?: SessionStore`, `resume?: string`, `model?`, `cwd?`,
+  `pathToClaudeCodeExecutable?`, `canUseTool?`, `permissionMode?`, `env?`, `allowedTools?`.
+- `SessionStore = { append(key, entries): Promise<void>; load(key): Promise<SessionStoreEntry[]|null>;
+  listSessions?(projectKey): Promise<{sessionId,mtime}[]>; delete?(key): Promise<void>;
+  listSubkeys?({projectKey,sessionId}): Promise<string[]> }`.
+- `SessionKey = { projectKey: string; sessionId: string; subpath?: string }` (undefined subpath = main
+  transcript; empty string invalid — store maps undefined→'' internally).
+- `SessionStoreEntry = { type: string; uuid?: string; timestamp?: string; [k]: unknown }` (opaque JSONL).
+- Messages: `SDKSystemMessage{subtype:'init'}` carries `session_id` (+ model/tools); `SDKResultMessage`
+  (success/error) ends a turn with `result`, `usage`, `total_cost_usd`; `SDKPartialAssistantMessage` /
+  `SDKAssistantMessage` carry text/thinking/tool blocks.
+
+## Part 1 — Clean-room PostgresSessionStore (testable now)
+- Schema (`apps/coder/src/schema.sql`): a generic append-only entry table
+  `claude_session_entries(id BIGSERIAL PK, project_key TEXT, session_id TEXT, subpath TEXT DEFAULT '',
+  entry JSONB, created_at TIMESTAMPTZ DEFAULT clock_timestamp())` + index `(project_key, session_id,
+  subpath, id)`. (The store is generic per the SDK's key; the chat↔session ownership lives in
+  `agent_sessions`, not here.)
+- `apps/coder/src/services/backends/claude-session-store.ts`: `PostgresSessionStore` implementing the
+  real `SessionStore` type over `Sql`. `append` = ordered multi-INSERT (id = order); `load` = SELECT
+  ORDER BY id → array or null; `listSessions` = group main-transcript rows, mtime = max(created_at) ms;
+  `delete` = scoped delete (subpath given → that subpath; omitted → whole session); `listSubkeys` =
+  DISTINCT non-'' subpaths. Pure SQL, no SDK import needed beyond the `SessionStore` type.
+- Tests `__tests__/claude-session-store.test.ts` (DB-opt-in, mirror `checkpoints.test.ts`): append→load
+  round-trip + order, null on unseen key, subpath isolation (main vs subagent), listSessions mtime,
+  delete scoping, listSubkeys.
+
+## Part 2 — ClaudeSdkBackend + wiring (live pump needs host smoke)
+- `agent_sessions.backend` CHECK adds `'claude_sdk'`.
+- `apps/coder/src/services/backends/claude-sdk.ts`: a `ClaudeSdkBackend` implementing `AgentBackend`
+  (mirror `warm-acp.ts`/`opencode-server.ts`). `ensureSession` resolves the resume id from
+  `agent_sessions(chat_id,'claude').agent_session_id`; `prompt` drives one persistent `query()` in
+  streaming-input mode (a pushable `AsyncIterable<SDKUserMessage>` fed per turn) with
+  `{ sessionStore, resume, model, cwd: worktreePath, pathToClaudeCodeExecutable: installPath }`,
+  reads the `AsyncGenerator<SDKMessage>` until `result`, captures `session_id` from the `init` message
+  and persists it to `agent_sessions`. A pure `mapSdkMessage(msg): AgentEvent[]` (unit-tested) maps
+  partial/assistant/tool/thinking → the existing `AgentEvent` union; `result.usage`/`total_cost_usd`
+  accumulate onto `agent_sessions` (like opencode U.6). `isBusy`/`closeSession`/crash mirror the ACP
+  backend.
+- Routing: add `claude` to the warm path (`warm-acp-routing.ts` or a sibling `shouldUseClaudeSdk`),
+  with the existing PTY `runExternalAgent` kept as the **fallback** (session-less creators + if the SDK
+  backend fails to start). Provider registry: claude stays selectable; transport reflects the SDK path.
+- Frames + persistence identical to the warm-ACP path (`persistExternalAgentTurn`, broker frames).
+
+## Verify
+- Part 1: `pnpm -C apps/coder test` + DB-opt-in store tests against dev postgres; build clean.
+- Part 2: `pnpm -C apps/coder build` + `npx tsc -p apps/coder/tsconfig.json --noEmit` (typechecks
+  against the REAL SDK types) + pure-mapper unit tests. **Live pump + resume across turns: host smoke
+  against real `claude` (auth required) — cannot run from the dev container.**
+
+## Open flags
+- SDK peer-deps want `zod@^4`; workspace is `zod@3.25.76` (installed with a warning) — watch at runtime.
+- `pathToClaudeCodeExecutable` from `available_agents.install_path`; the SDK spawns the same `claude`
+  binary the PTY path uses. ANTHROPIC auth/env must reach the child (host concern).

openspec/changes/mistake-tracker-file-ledger/proposal.md

@@ -0,0 +1,70 @@
+# MistakeTracker + file-provenance ledger (#12)
+
+**Status:** in progress (started 2026-06-01)
+**Source:** `boocode_code_review_v2.md` §1 #12, §5e (cline — algorithm-reimplemented, not vendored).
+
+Two native-inference (apps/server) hardening features. One cohesive backend change (they share
+`TurnArgs` + the tool-phase observation point) + a small frontend sentinel render.
+
+## Part A — MistakeTracker (heterogeneous-failure recovery)
+
+Complements the doom-loop guard (`sentinels.ts:detectDoomLoop`, which only catches *identical*
+repeats) by catching a run of consecutive tool **failures** the model isn't recovering from.
+
+- New pure `apps/server/src/services/inference/mistake-tracker.ts` (mirrors `detectDoomLoop`):
+  - `FailureKind = 'zod_reject' | 'tool_not_found' | 'exec_error' | 'api_error' | 'permission_denied'`
+    (all already distinguished in `tool-phase.ts:executeToolCall`).
+  - `MISTAKE_THRESHOLD = 3`.
+  - State `{ run: FailureKind[]; nudges: number }` — `run` is the current consecutive-failure streak,
+    reset on ANY successful tool step; `nudges` counts recovery injections not yet cleared by a success.
+  - `recordStep(state, outcome)` where outcome is a failure kind or `'success'`.
+  - `detectMistakePattern(state): 'nudge' | 'escalate' | null` — `run.length >= 3` → `'nudge'` the first
+    time (`nudges === 0`), `'escalate'` if it trips again while `nudges >= 1` (no intervening success).
+- Lives in `TurnArgs` (loop-local, reset per `runInference`, like `recentToolCalls`).
+- Integration in `turn.ts` loop: after each tool phase, `recordStep` per tool outcome; then
+  `detectMistakePattern`:
+  - `'nudge'` (decision: soft + escalate): append a transient **model-facing** recovery-guidance system
+    message to the NEXT turn's payload (re-read schemas, verify paths exist before acting, try a
+    different approach — not retry variations), insert a `mistake_recovery` UI sentinel
+    (`escalated:false`), bump `nudges`, reset `run`. Loop continues.
+  - `'escalate'`: stop the turn (break), insert a `mistake_recovery` sentinel (`escalated:true`,
+    `can_continue:true`, cap-hit-style), finalize. Prevents heterogeneous failures from burning the
+    whole step budget.
+
+## Part B — File-provenance ledger (Read-only)
+
+- Accumulate file paths read by `view_file`/`grep`/`find_files`/`list_dir` into `TurnArgs.filesRead:
+  Set<string>` (recorded at the tool-phase, like the failure outcomes).
+- On compaction (`compaction.ts:buildPrompt`), inject a deterministic, sorted `## Files Read` list into
+  the summary prompt context so the summarizer merges it into the rolling summary — **no new
+  table/column**; it propagates as summary text across compactions. `compaction-prompt.ts`'s
+  `SUMMARY_TEMPLATE` already has a `## Relevant Files` section to extend/merge with.
+- BooChat is **read-only** (no write tools on apps/server) → "Files Modified" is N/A here; only
+  "Files Read". (The apps/coder write side can add "Modified" later.)
+
+## Sentinel contract (pinned — backend + frontend must match)
+
+New sentinel kind on `MessageMetadata` in BOTH `apps/server/src/types/api.ts` AND
+`apps/web/src/api/types.ts`:
+```
+{ kind: 'mistake_recovery'; failure_kinds: string[]; count: number; escalated: boolean; can_continue?: boolean }
+```
+- `role='system'`, `status='complete'`, stripped from the LLM payload via `isAnySentinel` in
+  `payload.ts` (UI-only) and `compaction.ts:buildHeadPayload`.
+- Frontend render branch in `apps/web/src/components/MessageBubble.tsx`: `escalated:false` →
+  "Hit repeated different errors — recovery guidance injected, continuing." `escalated:true` →
+  "Repeated errors persisted — stopped the turn." (mirror the doom-loop/cap-hit branches).
+
+## Decisions (2026-06-01)
+- MistakeTracker intervention: **soft nudge + escalate**.
+- **UI sentinel** for recovery (`mistake_recovery`).
+
+## Files (backend, one agent) / (frontend, one agent)
+- Backend: `mistake-tracker.ts` (new), `turn.ts`, `tool-phase.ts`, `sentinels.ts`,
+  `sentinel-summaries.ts`, `payload.ts`, `compaction.ts`, `compaction-prompt.ts`, `types/api.ts` +
+  tests (`mistake-tracker.test.ts`, ledger/compaction assertions).
+- Frontend: `apps/web/src/api/types.ts` (MessageMetadata arm) + `MessageBubble.tsx` (render branch).
+  MUST NOT touch Sam's WIP web files.
+
+## Verify
+- `pnpm -C apps/server test`; `pnpm -C apps/server build`; `npx tsc -p apps/web/tsconfig.app.json --noEmit`

pnpm-lock.yaml

@@ -51,6 +51,9 @@ importers:
       '@agentclientprotocol/sdk':
         specifier: ^0.22.1
         version: 0.22.1(zod@3.25.76)
+      '@anthropic-ai/claude-agent-sdk':
+        specifier: ^0.3.159
+        version: 0.3.159(@anthropic-ai/sdk@0.100.1(zod@3.25.76))(@modelcontextprotocol/sdk@1.29.0(zod@3.25.76))(zod@3.25.76)
       '@boocode/server':
         specifier: workspace:*
         version: link:../server
@@ -317,6 +320,63 @@ packages:
     resolution: {integrity: sha512-UrcABB+4bUrFABwbluTIBErXwvbsU/V7TZWfmbgJfbkwiBuziS9gxdODUyuiecfdGQ85jglMW6juS3+z5TsKLw==}
     engines: {node: '>=10'}
 
+  '@anthropic-ai/claude-agent-sdk-darwin-arm64@0.3.159':
+    resolution: {integrity: sha512-3nnH4yUNJVSyaU5DBlGw2yxc4zlnVvAnc9UOe+La47QVG7/dN+rWAgn4zCbqKk9bWFLDQ1Ek0r56EZE1Qo4UKQ==}
+    cpu: [arm64]
+    os: [darwin]
+
+  '@anthropic-ai/claude-agent-sdk-darwin-x64@0.3.159':
+    resolution: {integrity: sha512-iv+NRjz+t4Q1R2+kLdDbccSo3b0wedVJ9jMT3noznOVojZHzgkxVpTvt36/XkXV0rqIDQ5H18bBYIZZzOXu7mg==}
+    cpu: [x64]
+    os: [darwin]
+
+  '@anthropic-ai/claude-agent-sdk-linux-arm64-musl@0.3.159':
+    resolution: {integrity: sha512-WvwiQBWt3tdu5EwqjpDZszI6p2uetYsw4Cxc6ptO/SmLIYXcDienP8nmirZdsZrS+Gzk6imgY0IY5mmNaRhelQ==}
+    cpu: [arm64]
+    os: [linux]
+
+  '@anthropic-ai/claude-agent-sdk-linux-arm64@0.3.159':
+    resolution: {integrity: sha512-FlsS5M4GCpzsQVaNDFF8dRgFGR3QwyAHZFl/xM/2Y2BqVBH+NH17RpKQSJxr1qr41QnsNkinMnu2iSKoc33hKg==}
+    cpu: [arm64]
+    os: [linux]
+
+  '@anthropic-ai/claude-agent-sdk-linux-x64-musl@0.3.159':
+    resolution: {integrity: sha512-kFH6RC2YJbPc8XWRNy/wL4YU7LzdJjSwAdH488sVzIif3q+TrvVrV5y/IW0+MLmta+CKIqtFYpGaucsJYvj7Eg==}
+    cpu: [x64]
+    os: [linux]
+
+  '@anthropic-ai/claude-agent-sdk-linux-x64@0.3.159':
+    resolution: {integrity: sha512-uNPEC/iRzVb4bEdzs0KAz1zV7i1PVGEZZnJTQyi1OtgVa81sAoH/H0CbbzDiTsquKdaESf+1DSSEkUlfZmMUEw==}
+    cpu: [x64]
+    os: [linux]
+
+  '@anthropic-ai/claude-agent-sdk-win32-arm64@0.3.159':
+    resolution: {integrity: sha512-WN1QEZGgWXz9GMl61QU6j9E+LEF5plki87bL2xsGwuCPzK+OeVPQU55pabuP8P+vFBFHUo3Y9OlTVyZHnUzmAQ==}
+    cpu: [arm64]
+    os: [win32]
+
+  '@anthropic-ai/claude-agent-sdk-win32-x64@0.3.159':
+    resolution: {integrity: sha512-Ty4seccD+dTDX5hhj89IUELZd/LkxO5O43Uiz5Mo8ZJktoX38SK4XMZlBS935QdqTFLRvPL0hvK4Lt4dTOqzPw==}
+    cpu: [x64]
+    os: [win32]
+
+  '@anthropic-ai/claude-agent-sdk@0.3.159':
+    resolution: {integrity: sha512-Xh1oVMIK6N3KsiNIhqNH8ZK90zjRmAEL9d1Md8ZlGdHJE+HhdMYdBadujc3KEkV0uufsEUvYp+A3fDenfypGSA==}
+    engines: {node: '>=18.0.0'}
+    peerDependencies:
+      '@anthropic-ai/sdk': '>=0.93.0'
+      '@modelcontextprotocol/sdk': ^1.29.0
+      zod: ^4.0.0
+
+  '@anthropic-ai/sdk@0.100.1':
+    resolution: {integrity: sha512-RANcEe7LpiLczkKGOwoXOTuFdPhuubS0i4xaAKOMpcqc55YO0mukgxppV7eygx3DXNjxWT6RYOLPyOy0aIAmwg==}
+    hasBin: true
+    peerDependencies:
+      zod: ^3.25.0 || ^4.0.0
+    peerDependenciesMeta:
+      zod:
+        optional: true
+
   '@babel/code-frame@7.29.0':
     resolution: {integrity: sha512-9NhCeYjq9+3uxgdtp20LSiJXJvN0FeCtNGpJxuMFZ1Kv3cWUNb6DOhJwUvcVCzKGR66cw4njwM6hrJLqgOwbcw==}
     engines: {node: '>=6.9.0'}
@@ -446,6 +506,10 @@ packages:
     peerDependencies:
       '@babel/core': ^7.0.0-0
 
+  '@babel/runtime@7.29.7':
+    resolution: {integrity: sha512-Nq8OhGWiZIZGV6hLHoyAKLLcJihP/xFeBMGJoUrxTX2psI8dCifzLhZISFb+VWS3wFMRDmCGw5R+dOySCqPLhw==}
+    engines: {node: '>=6.9.0'}
+
   '@babel/template@7.28.6':
     resolution: {integrity: sha512-YA6Ma2KsCdGb+WC6UpBVFJGXL58MDA6oyONbjyF/+5sBgxY/dwkhLogbMT2GXXyU84/IhRw/2D1Os1B/giz+BQ==}
     engines: {node: '>=6.9.0'}
@@ -1787,6 +1851,9 @@ packages:
     resolution: {integrity: sha512-tlqY9xq5ukxTUZBmoOp+m61cqwQD5pHJtFY3Mn8CA8ps6yghLH/Hw8UPdqg4OLmFW3IFlcXnQNmo/dh8HzXYIQ==}
     engines: {node: '>=18'}
 
+  '@stablelib/base64@1.0.1':
+    resolution: {integrity: sha512-1bnPQqSxSuc3Ii6MhBysoWCg58j97aUjuCSZrGSmDxNqtytIi0k8utUenAwTZN4V5mXXYGsVUI9zeBqy+jBOSQ==}
+
   '@standard-schema/spec@1.1.0':
     resolution: {integrity: sha512-l2aFy5jALhniG5HgqrD6jXLi/rUWrKvqN/qJx6yoJsgKhblVd+iqqU4RCXavm/jPityDo5TCvKMnpjKnOriy0w==}
 
@@ -2528,6 +2595,9 @@ packages:
   fast-querystring@1.1.2:
     resolution: {integrity: sha512-g6KuKWmFXc0fID8WWH0jit4g0AGBoJhCkJMb1RmbsSEUNvQ+ZC8D6CUZ+GtF8nMzSPXnhiePyyqqipzNNEnHjg==}
 
+  fast-sha256@1.3.0:
+    resolution: {integrity: sha512-n11RGP/lrWEFI/bWdygLxhI+pVeo1ZYIVwvvPkW7azl/rOy+F3HYRZ2K5zeE9mmkhQppyv9sQFx0JM9UabnpPQ==}
+
   fast-string-truncated-width@3.0.3:
     resolution: {integrity: sha512-0jjjIEL6+0jag3l2XWWizO64/aZVtpiGE3t0Zgqxv0DPuxiMjvB3M24fCyhZUO4KomJQPj3LTSUnDP3GpdwC0g==}
 
@@ -2873,6 +2943,10 @@ packages:
   json-schema-ref-resolver@1.0.1:
     resolution: {integrity: sha512-EJAj1pgHc1hxF6vo2Z3s69fMjO1INq6eGHXZ8Z6wCQeldCuwxGK9Sxf4/cScGn3FZubCVUehfWtcDM/PLteCQw==}
 
+  json-schema-to-ts@3.1.1:
+    resolution: {integrity: sha512-+DWg8jCJG2TEnpy7kOm/7/AxaYoaRbjVB4LFZLySZlWn8exGs3A4OLJR966cVvU26N7X9TWxl+Jsw7dzAqKT6g==}
+    engines: {node: '>=16'}
+
   json-schema-traverse@1.0.0:
     resolution: {integrity: sha512-NM8/P9n3XjXhIZn1lLhkFaACTOURQXjWhV4BA/RnOv8xvgqtqpAX9IO4mRQxSx1Rlo4tqzeqb0sOlruaOy3dug==}
 
@@ -3756,6 +3830,9 @@ packages:
   stackback@0.0.2:
     resolution: {integrity: sha512-1XMJE5fQo1jGH6Y/7ebnwPOBEkIEnT4QF32d5R1+VXdXveM0IBMJt8zfaxX1P3QhVwrYe+576+jkANtSS2mBbw==}
 
+  standardwebhooks@1.0.0:
+    resolution: {integrity: sha512-BbHGOQK9olHPMvQNHWul6MYlrRTAOKn03rOe4A8O3CLWhNf4YHBqq2HJKKC+sfqpxiBY52pNeesD6jIiLDz8jg==}
+
   statuses@2.0.1:
     resolution: {integrity: sha512-RwNA9Z/7PrK06rYLIzFMlaF+l73iwpzsqRIFgbMLbTcLD6cOao82TaWefPXQvB2fOC4AjuYSEndS7N/mTCbkdQ==}
     engines: {node: '>= 0.8'}
@@ -3899,6 +3976,9 @@ packages:
   trough@2.2.0:
     resolution: {integrity: sha512-tmMpK00BjZiUyVyvrBK7knerNgmgvcV/KLVyuma/SC+TQN167GrMRciANTz09+k3zW8L8t60jWO1GpfkZdjTaw==}
 
+  ts-algebra@2.0.0:
+    resolution: {integrity: sha512-FPAhNPFMrkwz76P7cdjdmiShwMynZYN6SgOujD1urY4oNm80Ou9oMdmbR45LotcKOXoy7wSmHkRFE6Mxbrhefw==}
+
   ts-morph@26.0.0:
     resolution: {integrity: sha512-ztMO++owQnz8c/gIENcM9XfCEzgoGphTv+nKpYNM1bgsdOVC/jRZuEBf6N+mLLDNg68Kl+GgUZfOySaRiG1/Ug==}
 
@@ -4194,6 +4274,52 @@ snapshots:
 
   '@alloc/quick-lru@5.2.0': {}
 
+  '@anthropic-ai/claude-agent-sdk-darwin-arm64@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-darwin-x64@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-linux-arm64-musl@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-linux-arm64@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-linux-x64-musl@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-linux-x64@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-win32-arm64@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk-win32-x64@0.3.159':
+    optional: true
+
+  '@anthropic-ai/claude-agent-sdk@0.3.159(@anthropic-ai/sdk@0.100.1(zod@3.25.76))(@modelcontextprotocol/sdk@1.29.0(zod@3.25.76))(zod@3.25.76)':
+    dependencies:
+      '@anthropic-ai/sdk': 0.100.1(zod@3.25.76)
+      '@modelcontextprotocol/sdk': 1.29.0(zod@3.25.76)
+      zod: 3.25.76
+    optionalDependencies:
+      '@anthropic-ai/claude-agent-sdk-darwin-arm64': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-darwin-x64': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-linux-arm64': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-linux-arm64-musl': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-linux-x64': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-linux-x64-musl': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-win32-arm64': 0.3.159
+      '@anthropic-ai/claude-agent-sdk-win32-x64': 0.3.159
+
+  '@anthropic-ai/sdk@0.100.1(zod@3.25.76)':
+    dependencies:
+      json-schema-to-ts: 3.1.1
+      standardwebhooks: 1.0.0
+    optionalDependencies:
+      zod: 3.25.76
+
   '@babel/code-frame@7.29.0':
     dependencies:
       '@babel/helper-validator-identifier': 7.28.5
@@ -4367,6 +4493,8 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
+  '@babel/runtime@7.29.7': {}
+
   '@babel/template@7.28.6':
     dependencies:
       '@babel/code-frame': 7.29.0
@@ -5618,6 +5746,8 @@ snapshots:
 
   '@sindresorhus/merge-streams@4.0.0': {}
 
+  '@stablelib/base64@1.0.1': {}
+
   '@standard-schema/spec@1.1.0': {}
 
   '@tailwindcss/node@4.3.0':
@@ -6386,6 +6516,8 @@ snapshots:
     dependencies:
       fast-decode-uri-component: 1.0.1
 
+  fast-sha256@1.3.0: {}
+
   fast-string-truncated-width@3.0.3: {}
 
   fast-string-width@3.0.2:
@@ -6727,6 +6859,11 @@ snapshots:
     dependencies:
       fast-deep-equal: 3.1.3
 
+  json-schema-to-ts@3.1.1:
+    dependencies:
+      '@babel/runtime': 7.29.7
+      ts-algebra: 2.0.0
+
   json-schema-traverse@1.0.0: {}
 
   json-schema-typed@8.0.2: {}
@@ -7939,6 +8076,11 @@ snapshots:
 
   stackback@0.0.2: {}
 
+  standardwebhooks@1.0.0:
+    dependencies:
+      '@stablelib/base64': 1.0.1
+      fast-sha256: 1.3.0
+
   statuses@2.0.1: {}
 
   statuses@2.0.2: {}
@@ -8061,6 +8203,8 @@ snapshots:
 
   trough@2.2.0: {}
 
+  ts-algebra@2.0.0: {}
+
   ts-morph@26.0.0:
     dependencies:
       '@ts-morph/common': 0.27.0