Merge remote-tracking branch 'origin/master' into worktree/semantic-session-checkpoints

# Conflicts:
#	docs/architecture.md
#	docs/event-producer-consumer.md
#	examples/acp-agent/tests/snapshots/cancel-tool-calls/session.jsonl
#	packages/core/agent-loop/README.md
#	packages/core/agent-loop/src/loop.ts
#	packages/core/agent-loop/tests/cancel.spec.ts

packages/session-persistence/session-checkpoint-policy/README.md

@@ -16,7 +16,7 @@ This zero-config function plugin consumes `ctx.sessions`, `ctx.llm`, `ctx.tools`
 
 Persistence and checkpoint scheduling are intentionally separate Cordis plugins. A persistence backend makes each requested `session/flush` durable; this policy chooses the request, tool-dispatch, and completed-step checkpoints. Loading a backend without this policy is valid and retains checkpoints requested by the loop, including final `turn/end`, but crash recovery may lose the rest of an in-flight turn. First-party persisted apps and runtimes mount both plugins explicitly; a specialized deployment may deliberately omit or replace the policy.
 
-The policy wraps `llm/stream` lazily, so the downstream stream is not constructed until the live session's buffered request events are durable. It wraps `tools/execute` after pre-execute policy and guards; a top-level tool body runs only after its recorded call is durable. If cancellation lands while that flush is pending, the wrapper returns the canonical `ABORTED` result without entering the tool body. Nested tool dispatches reuse the outer model-visible call's checkpoint. `agent/post-step` persists the complete response/result batch before continuation work.
+The policy wraps `llm/stream` lazily, so the downstream stream is not constructed until the live session's buffered request events are durable. It wraps `tools/execute` after pre-execute policy and guards; a top-level tool body runs only after its recorded call is durable. If cancellation lands while that flush is pending, the wrapper returns the canonical `ABORTED_BEFORE_DISPATCH` result without entering the tool body. Nested tool dispatches reuse the outer model-visible call's checkpoint. `agent/post-step` persists the complete response/result batch before continuation work.
 
 The loop records its assistant message and ordered tool results before dispatching `agent/post-step`, so the policy always captures that core batch. An event appended by another `agent/post-step` listener is captured at this checkpoint only when that listener is registered before the policy; Cordis registration order is the explicit composition rule for such extensions.
 

packages/session-persistence/session-checkpoint-policy/src/index.ts

@@ -7,7 +7,7 @@
 import type { Context } from 'cordis'
 import type { Session } from '@deepseek-ai/dsh-session'
 import type { StreamChunk } from '@deepseek-ai/dsh-llm'
-import type { ToolExecutionResult } from '@deepseek-ai/dsh-tools'
+import { TOOL_ABORTED_BEFORE_DISPATCH, type ToolExecutionResult } from '@deepseek-ai/dsh-tools'
 import type {} from '@deepseek-ai/dsh-agent'
 import type {} from '@deepseek-ai/dsh-session-persistence'
 
@@ -38,11 +38,11 @@ function afterCheckpoint(
 }
 
 /** Materialize the canonical result for a call cancelled before tool dispatch. */
-function abortedToolResult(): ToolExecutionResult {
+function abortedBeforeDispatchResult(): ToolExecutionResult {
   return {
-    content: [{ type: 'text', text: 'Error: tool call skipped because the step was aborted before execution' }],
+    content: [{ type: 'text', text: 'Error: tool call aborted before dispatch' }],
     isError: true,
-    error: { name: 'AbortError', code: 'ABORTED' },
+    error: { name: 'AbortError', code: TOOL_ABORTED_BEFORE_DISPATCH },
   }
 }
 
@@ -67,7 +67,7 @@ export function apply(ctx: Context): void {
   ctx.on('tools/execute', async (exec, next): Promise<ToolExecutionResult> => {
     if (exec.agent === undefined || exec.parent !== undefined) return next()
     await ctx.sessions.flush(exec.agent.session)
-    if (exec.signal?.aborted === true) return abortedToolResult()
+    if (exec.signal.aborted) return abortedBeforeDispatchResult()
     return next()
   })
 

packages/session-persistence/session-checkpoint-policy/tests/session-checkpoint-policy.spec.ts

@@ -7,7 +7,7 @@ import SessionStore, { SessionId } from '@deepseek-ai/dsh-session'
 import type { SessionEvent, SessionHeader } from '@deepseek-ai/dsh-session'
 import SessionPersistence from '@deepseek-ai/dsh-session-persistence'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
-import ToolRegistry from '@deepseek-ai/dsh-tools'
+import ToolRegistry, { TOOL_ABORTED_BEFORE_DISPATCH } from '@deepseek-ai/dsh-tools'
 import * as checkpointPolicy from '../src/index.ts'
 
 const contexts: Context[] = []
@@ -126,6 +126,7 @@ describe('session-checkpoint-policy tool and step boundaries', () => {
 
     const pending = ctx.tools.execute({
       callId: CallId('write-1'), name: 'write', arguments: {}, agent,
+      signal: new AbortController().signal,
     })
     await Promise.resolve()
     expect(order).toEqual(['flush:start'])
@@ -161,9 +162,9 @@ describe('session-checkpoint-policy tool and step boundaries', () => {
     gate.resolve(undefined)
 
     await expect(pending).resolves.toEqual({
-      content: [{ type: 'text', text: 'Error: tool call skipped because the step was aborted before execution' }],
+      content: [{ type: 'text', text: 'Error: tool call aborted before dispatch' }],
       isError: true,
-      error: { name: 'AbortError', code: 'ABORTED' },
+      error: { name: 'AbortError', code: TOOL_ABORTED_BEFORE_DISPATCH },
     })
     expect(order).toEqual(['flush:start', 'flush:end'])
   })
@@ -180,6 +181,7 @@ describe('session-checkpoint-policy tool and step boundaries', () => {
     })
     const result = await ctx.tools.execute({
       callId: CallId('write-2'), name: 'write', arguments: {}, agent,
+      signal: new AbortController().signal,
     })
     expect(result.isError).toBe(true)
     expect(result.content).toEqual([{ type: 'text', text: 'Error: disk unavailable' }])
@@ -196,6 +198,7 @@ describe('session-checkpoint-policy tool and step boundaries', () => {
     await ctx.tools.execute({
       callId: CallId('nested-1'), name: 'nested', arguments: {}, agent,
       parent: Symbol('outer') as never,
+      signal: new AbortController().signal,
     })
     expect(flushes).toBe(0)
   })