Merge remote-tracking branch 'origin/master' into codex/enforce-tool-cancellation

# Conflicts:
#	docs/architecture.md
#	packages/core/agent-loop/README.md

packages/core/agent-loop/README.md

@@ -56,7 +56,7 @@ The driver owns one agent for its lifetime and runs inside `ctx.agents.withIniti
 
 Every provider call that reaches a successful finish appends exactly one `assistant/message` completion anchor, including content-less calls and `max-tokens` finishes. A successful `agent/step-result` stores its transformed content; a rejected result records empty content before the original failure continues. The anchor retains exact chunk provenance (`[]` for a stream with no chunks) and usage when available, while empty content stays out of derived message history.
 
-Plugin failure ends the current turn, not the loop. Only final adapter dispatch/iteration failures and terminal in-band error or aborted finishes enter `agent/request-error`; middleware, result processing, tools, and `agent/post-step` remain ordinary turn failures. Recovery receives the exact live error, immutable provider facts, and immutable prior failures after the failed step closes. A retry rebuilds from the durable log in a new numbered step, success clears the consecutive history, and exhaustion records the structured failure once on `turn/end`. Cancellation clears pending work and aborts the current step without leaking to the next prompt; undispatched model tool calls receive synthetic `tool/call` and `ABORTED_BEFORE_DISPATCH` result pairs. Terminal continuation stops remain authoritative through turn close and durability flush.
+Plugin failure ends the current turn, not the loop. Only final adapter dispatch/iteration failures and terminal in-band error or aborted finishes enter `agent/request-error`; middleware, result processing, tools, and `agent/post-step` remain ordinary turn failures. Recovery receives the exact live error, immutable provider facts, and immutable prior failures after the failed step closes. A retry rebuilds from the durable log in a new numbered step, success clears the consecutive history, and exhaustion records the structured failure once on `turn/end`. Effective cancellation resolves its reason and emits `agent/cancel-requested` before clearing pending work or aborting the current step; notification failures are contained, queued work added by an observer is included in the same broad clear, and idle cancellation emits nothing. Undispatched model tool calls receive synthetic `tool/call` and `ABORTED_BEFORE_DISPATCH` result pairs. Terminal continuation stops remain authoritative through turn close and durability flush.
 
 Within a step, exclusive calls form barriers; parallel-safe calls use a bounded rolling pool and are reclassified before start. Only dispatch/body overlaps. Policy, durable results, and result context remain model-ordered. Abort stops new calls, drains started results, then drains accepted batch context before the turn closes through the normal abort path.
 

packages/core/agent-loop/src/agent.ts

@@ -331,13 +331,18 @@ export class ReactLoopAgent implements Agent {
   }
 
   cancel(reason?: string): void {
+    const resolvedReason = reason ?? 'cancelled'
     // Arm only for current work; an idle marker would cancel the next prompt.
     if (this._status === 'running' || this.currentAbort !== undefined || this.#inbox.hasQueued || this.#inbox.hasSteering) {
       this.cancelRequested = true
       // Capture the resolved reason for the marker-only windows (pre-step /
       // continuation). The mid-step path reads it from abort.signal.reason
       // below; the marker path reads it via the LoopHandle's cancelReason().
-      this.cancelReason = reason ?? 'cancelled'
+      this.cancelReason = resolvedReason
+      // Coordination consumers must update their own state before this call
+      // clears the inbox or aborts the step. Notification failures are
+      // contained by the fused dispatcher and cannot veto cancellation.
+      agentEvents(this.loopCtx, this).emit('agent/cancel-requested', resolvedReason)
     }
     // Drop all pending queued + steering work (un-started prompts never run; the
     // cancelled turn's steering is not re-enqueued). Cleared directly even when
@@ -347,7 +352,7 @@ export class ReactLoopAgent implements Agent {
     // Interrupt an in-flight step immediately (the running turn observes the
     // abort and ends `aborted`). The marker covers the windows where no step is
     // running (pre-step, continuation).
-    this.currentAbort?.abort(reason ?? 'cancelled')
+    this.currentAbort?.abort(resolvedReason)
   }
 
   /**

packages/core/agent-loop/tests/cancel.spec.ts

@@ -7,7 +7,7 @@
  * @module dsh-agent-loop/tests/cancel
  */
 
-import { describe, expect, it } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import LlmService, { type Message } from '@deepseek-ai/dsh-llm'
 import SessionStore, { SessionId, TurnEndReason } from '@deepseek-ai/dsh-session'
@@ -55,6 +55,33 @@ function userTexts(agent: Agent): string[] {
 }
 
 describe('Agent.cancel()', () => {
+  it('notifies every observer before clearing work and contains listener failures', async () => {
+    const adapter = new MockAdapter([textResponse('must remain unused')])
+    const ctx = await harness(adapter)
+    const agent = ctx.agentLoop.create(SessionId('cancel-event'), { provider: 'mock', model: 'mock' })
+    const warned = vi.spyOn(ctx.logger, 'warn').mockImplementation(() => {})
+    const seen: string[] = []
+    ctx.on('agent/cancel-requested', (subject, reason) => {
+      if (subject !== agent) return
+      seen.push(`first:${reason}`)
+      subject.send([{ type: 'text', text: 'queued by cancel observer' }])
+      throw new Error('observer failed')
+    })
+    ctx.on('agent/cancel-requested', (subject, reason) => {
+      if (subject === agent) seen.push(`second:${reason}`)
+    })
+
+    send(agent, 'drop me')
+    agent.cancel()
+    await new Promise(resolve => setTimeout(resolve, 30))
+    agent.cancel('idle no-op')
+
+    expect(seen).toEqual(['first:cancelled', 'second:cancelled'])
+    expect(userTexts(agent)).toEqual([])
+    expect(adapter.requests).toHaveLength(0)
+    expect(warned).toHaveBeenCalledWith(expect.stringContaining('agent/cancel-requested'))
+  })
+
   it('cancel() on an idle agent with nothing queued is a no-op; the next prompt runs (F2 leak guard)', async () => {
     const adapter = new MockAdapter([textResponse('reply')])
     const ctx = await harness(adapter)

packages/core/agent-loop/tests/contract-regressions.spec.ts

@@ -531,7 +531,7 @@ describe('steering from late extension points is never stranded', () => {
     expect(JSON.stringify(adapter.requests[1]!.messages)).toContain('one more thing')
   })
 
-  it('steer() from a step/end session-event listener forces a SAME-TURN next step (/goal pattern)', async () => {
+  it('steer() from a step/end session-event listener forces a SAME-TURN next step', async () => {
     // Assert the same-turn shape; content alone cannot distinguish re-enqueue.
     const adapter = new MockAdapter([
       textResponse('no tools, would stop'),