Merge commit 'refs/codex-unblock/20260722-pr338-master' into HEAD

# Conflicts:
#	docs/event-producer-consumer.md
#	examples/acp-agent/tests/acp.snapshot.ts
#	packages/core/session/src/index.ts
#	packages/examples/acp-demo/src/index.ts
#	packages/session-persistence/session-persistence-jsonl/src/format.ts
#	vitest.config.ts

packages/examples/acp-demo/README.md

@@ -15,13 +15,14 @@ stdout is the ACP JSON-RPC channel, so the cluster is defined as much by what it
 | `@deepseek-ai/dsh-command-goal` | the discoverable direct `/goal` producer; the app enables the spine's persisted-goal stack with it |
 | `@deepseek-ai/dsh-user-interaction` | the human question/answer seam used by clients that can complete ACP elicitation requests |
 | `@deepseek-ai/dsh-session-persistence-jsonl` | durable JSONL session log (the bridge advertises `loadSession`) |
+| `@deepseek-ai/dsh-session-checkpoint-policy` | semantic durability barriers before model requests and top-level tool effects, plus completed-step checkpoints |
 | `@deepseek-ai/dsh-acp` | the bridge that owns stdout for JSON-RPC and provides ACP-backed user answers when a leaf explicitly exposes a user-question tool |
 | ~~`@deepseek-ai/dsh-tool-ask-user`~~ | **omitted by default** — ACP elicitation support is still client-dependent, so leaves must opt in deliberately |
 | ~~`@deepseek-ai/dsh-user-approval`~~ | **omitted by default** — permission policy is deployment-specific; sandbox/approval leaves opt in and the ACP bridge then supplies the answerer |
 | ~~console logger~~ | **omitted** — it writes to stdout and would corrupt the protocol frames ([the stdout-purity footgun](../../ui/acp/README.md)) |
 | ~~`hmr`~~ | **omitted** — the editor owns the subprocess |
 
-Because the package wires no logger entry, an ACP leaf has **nothing to get wrong by default**: it only picks backends. A leaf author can still add `@cordisjs/plugin-logger-console` as a sibling entry, so the rule remains: never add a stdout logger to an ACP leaf; use a stderr exporter instead.
+The app owns this cluster through one ordered Cordis effect. Teardown drains the ACP bridge before removing the checkpoint policy or persistence backend, so a graceful disconnect persists the real closing `step/end` and `turn/end` events rather than leaving crash recovery to synthesize them. Because the package wires no logger entry, an ACP leaf has **nothing to get wrong by default**: it only picks backends. A leaf author can still add `@cordisjs/plugin-logger-console` as a sibling entry, so the rule remains: never add a stdout logger to an ACP leaf; use a stderr exporter instead.
 
 ## Config
 

packages/examples/acp-demo/package.json

@@ -43,6 +43,7 @@
     "@deepseek-ai/dsh-agent-spine-demo": "^0.0.1",
     "@deepseek-ai/dsh-app-boot": "^0.0.1",
     "@deepseek-ai/dsh-invariants": "^0.0.1",
+    "@deepseek-ai/dsh-session-checkpoint-policy": "^0.0.1",
     "@deepseek-ai/dsh-session-persistence-jsonl": "^0.0.1",
     "@deepseek-ai/dsh-tools": "^0.0.1",
     "@deepseek-ai/dsh-user-interaction": "^0.0.1",
@@ -60,6 +61,7 @@
     "@deepseek-ai/dsh-agent-spine-demo": "workspace:^",
     "@deepseek-ai/dsh-app-boot": "workspace:^",
     "@deepseek-ai/dsh-invariants": "workspace:^",
+    "@deepseek-ai/dsh-session-checkpoint-policy": "workspace:^",
     "@deepseek-ai/dsh-session-persistence-jsonl": "workspace:^",
     "@deepseek-ai/dsh-system-prompt": "workspace:^",
     "@deepseek-ai/dsh-tools": "workspace:^",

packages/examples/acp-demo/src/index.ts

@@ -1,7 +1,9 @@
 /**
  * The ACP server app: the default agent spine ({@link @deepseek-ai/dsh-agent-spine-demo}),
  * human-command registry, JSONL session persistence, and the
- * {@link @deepseek-ai/dsh-acp} bridge. It writes nothing to stdout.
+ * {@link @deepseek-ai/dsh-acp} bridge. The app owns those plugins through one
+ * ordered lifecycle so ACP sessions quiesce before persistence detaches. It
+ * writes nothing to stdout.
  * It pre-creates no agents and leaves adapters, executors, and optional tools to
  * the leaf, which must likewise avoid stdout loggers. Named exports are
  * required so Loader retains this plugin's `Config` schema (see
@@ -21,6 +23,7 @@ import SessionPersistenceJsonl, {
   JsonlCompressionSchema,
   type JsonlCompression,
 } from '@deepseek-ai/dsh-session-persistence-jsonl'
+import * as sessionCheckpointPolicy from '@deepseek-ai/dsh-session-checkpoint-policy'
 import UserInteractionService from '@deepseek-ai/dsh-user-interaction'
 
 export const name = 'acp-demo'
@@ -104,22 +107,27 @@ export const Config: z<Config> = z.object({
  * NO agents (its `agents` list defaults to `[]`) and carries the deployment
  * `persona`; the JSONL backend persists under `persistenceRoot`; the ACP
  * bridge owns stdout for JSON-RPC and creates one agent per `session/new`
- * from the provider/model pair. No logger, no `hmr` — stdout stays pure.
+ * from the provider/model pair. The composite effect unloads in reverse order,
+ * keeping checkpoint and persistence listeners attached until ACP agents have
+ * flushed their closing events. No logger, no `hmr` — stdout stays pure.
  */
 export function apply(ctx: Context, config: Config): void {
   const goals = config.goals ?? {}
-  ctx.plugin(CommandService)
-  if (goals !== false) ctx.plugin(commandGoal)
-  ctx.plugin(agentCore, { ...agentCore.pickSpineConfig(config), goals })
-  ctx.plugin(UserInteractionService)
-  // Same rationale as the Config schema above: each front door forwards its own
-  // persistence passthroughs rather than sharing a facade with stdio-demo.
-  /* jscpd:ignore-start */
-  ctx.plugin(SessionPersistenceJsonl, {
-    root: config.persistenceRoot ?? DEFAULT_PERSISTENCE_ROOT,
-    ...config.packChunks !== undefined ? { packChunks: config.packChunks } : {},
-    ...(config.persistenceCompression === undefined ? {} : { compression: config.persistenceCompression }),
-  })
-  /* jscpd:ignore-end */
-  ctx.plugin(acp, { provider: config.provider, model: config.model })
+  ctx.effect(function* () {
+    yield ctx.plugin(CommandService).dispose
+    if (goals !== false) yield ctx.plugin(commandGoal).dispose
+    yield ctx.plugin(agentCore, { ...agentCore.pickSpineConfig(config), goals }).dispose
+    yield ctx.plugin(UserInteractionService).dispose
+    // Same rationale as the Config schema above: each front door forwards its own
+    // persistence passthroughs rather than sharing a facade with stdio-demo.
+    /* jscpd:ignore-start */
+    yield ctx.plugin(SessionPersistenceJsonl, {
+      root: config.persistenceRoot ?? DEFAULT_PERSISTENCE_ROOT,
+      ...config.packChunks !== undefined ? { packChunks: config.packChunks } : {},
+      ...(config.persistenceCompression === undefined ? {} : { compression: config.persistenceCompression }),
+    }).dispose
+    /* jscpd:ignore-end */
+    yield ctx.plugin(sessionCheckpointPolicy).dispose
+    yield ctx.plugin(acp, { provider: config.provider, model: config.model }).dispose
+  }, 'acp-demo.composition')
 }

packages/examples/acp-demo/tests/built-bin.e2e.ts

@@ -35,7 +35,8 @@ const dshPackages = [
   'core/tools', 'core/agent-loop', 'llm/llm', 'bash/bash',
   'bash/bash-local', 'bash/tool-bash', 'context/workspace-context', 'support/invariants', 'ui/app-boot',
   'session-persistence/session-persistence',
-  'session-persistence/session-persistence-jsonl', 'ui/acp', 'examples/acp-demo', 'util/paths',
+  'session-persistence/session-checkpoint-policy', 'session-persistence/session-persistence-jsonl',
+  'ui/acp', 'examples/acp-demo', 'util/paths',
 ]
 const vendorPackages = [
   'cordis', 'loader', 'include', 'timer', 'hmr', 'logger-console',

packages/examples/acp-demo/tsconfig.json

@@ -44,6 +44,9 @@
     {
       "path": "../../ui/tool-ask-user"
     },
+    {
+      "path": "../../session-persistence/session-checkpoint-policy"
+    },
     {
       "path": "../../session-persistence/session-persistence-jsonl"
     },