feat: ACP thread-bound agents (#23580)

* docs: add ACP thread-bound agents plan doc

* docs: expand ACP implementation specification

* feat(acp): route ACP sessions through core dispatch and lifecycle cleanup

* feat(acp): add /acp commands and Discord spawn gate

* ACP: add acpx runtime plugin backend

* fix(subagents): defer transient lifecycle errors before announce

* Agents: harden ACP sessions_spawn and tighten spawn guidance

* Agents: require explicit ACP target for runtime spawns

* docs: expand ACP control-plane implementation plan

* ACP: harden metadata seeding and spawn guidance

* ACP: centralize runtime control-plane manager and fail-closed dispatch

* ACP: harden runtime manager and unify spawn helpers

* Commands: route ACP sessions through ACP runtime in agent command

* ACP: require persisted metadata for runtime spawns

* Sessions: preserve ACP metadata when updating entries

* Plugins: harden ACP backend registry across loaders

* ACPX: make availability probe compatible with adapters

* E2E: add manual Discord ACP plain-language smoke script

* ACPX: preserve streamed spacing across Discord delivery

* Docs: add ACP Discord streaming strategy

* ACP: harden Discord stream buffering for thread replies

* ACP: reuse shared block reply pipeline for projector

* ACP: unify streaming config and adopt coalesceIdleMs

* Docs: add temporary ACP production hardening plan

* Docs: trim temporary ACP hardening plan goals

* Docs: gate ACP thread controls by backend capabilities

* ACP: add capability-gated runtime controls and /acp operator commands

* Docs: remove temporary ACP hardening plan

* ACP: fix spawn target validation and close cache cleanup

* ACP: harden runtime dispatch and recovery paths

* ACP: split ACP command/runtime internals and centralize policy

* ACP: harden runtime lifecycle, validation, and observability

* ACP: surface runtime and backend session IDs in thread bindings

* docs: add temp plan for binding-service migration

* ACP: migrate thread binding flows to SessionBindingService

* ACP: address review feedback and preserve prompt wording

* ACPX plugin: pin runtime dependency and prefer bundled CLI

* Discord: complete binding-service migration cleanup and restore ACP plan

* Docs: add standalone ACP agents guide

* ACP: route harness intents to thread-bound ACP sessions

* ACP: fix spawn thread routing and queue-owner stall

* ACP: harden startup reconciliation and command bypass handling

* ACP: fix dispatch bypass type narrowing

* ACP: align runtime metadata to agentSessionId

* ACP: normalize session identifier handling and labels

* ACP: mark thread banner session ids provisional until first reply

* ACP: stabilize session identity mapping and startup reconciliation

* ACP: add resolved session-id notices and cwd in thread intros

* Discord: prefix thread meta notices consistently

* Discord: unify ACP/thread meta notices with gear prefix

* Discord: split thread persona naming from meta formatting

* Extensions: bump acpx plugin dependency to 0.1.9

* Agents: gate ACP prompt guidance behind acp.enabled

* Docs: remove temp experiment plan docs

* Docs: scope streaming plan to holy grail refactor

* Docs: refactor ACP agents guide for human-first flow

* Docs/Skill: add ACP feature-flag guidance and direct acpx telephone-game flow

* Docs/Skill: add OpenCode and Pi to ACP harness lists

* Docs/Skill: align ACP harness list with current acpx registry

* Dev/Test: move ACP plain-language smoke script and mark as keep

* Docs/Skill: reorder ACP harness lists with Pi first

* ACP: split control-plane manager into core/types/utils modules

* Docs: refresh ACP thread-bound agents plan

* ACP: extract dispatch lane and split manager domains

* ACP: centralize binding context and remove reverse deps

* Infra: unify system message formatting

* ACP: centralize error boundaries and session id rendering

* ACP: enforce init concurrency cap and strict meta clear

* Tests: fix ACP dispatch binding mock typing

* Tests: fix Discord thread-binding mock drift and ACP request id

* ACP: gate slash bypass and persist cleared overrides

* ACPX: await pre-abort cancel before runTurn return

* Extension: pin acpx runtime dependency to 0.1.11

* Docs: add pinned acpx install strategy for ACP extension

* Extensions/acpx: enforce strict local pinned startup

* Extensions/acpx: tighten acp-router install guidance

* ACPX: retry runtime test temp-dir cleanup

* Extensions/acpx: require proactive ACPX repair for thread spawns

* Extensions/acpx: require restart offer after acpx reinstall

* extensions/acpx: remove workspace protocol devDependency

* extensions/acpx: bump pinned acpx to 0.1.13

* extensions/acpx: sync lockfile after dependency bump

* ACPX: make runtime spawn Windows-safe

* fix: align doctor-config-flow repair tests with default-account migration (#23580) (thanks @osolmaz)

src/discord/monitor/message-handler.preflight.test.ts

@@ -1,5 +1,9 @@
 import { ChannelType } from "@buape/carbon";
 import { beforeEach, describe, expect, it } from "vitest";
+import {
+  __testing as sessionBindingTesting,
+  registerSessionBindingAdapter,
+} from "../../infra/outbound/session-binding-service.js";
 import {
   preflightDiscordMessage,
   resolvePreflightMentionRequirement,
@@ -7,25 +11,35 @@ import {
 } from "./message-handler.preflight.js";
 import {
   __testing as threadBindingTesting,
+  createNoopThreadBindingManager,
   createThreadBindingManager,
 } from "./thread-bindings.js";
 
 function createThreadBinding(
-  overrides?: Partial<import("./thread-bindings.js").ThreadBindingRecord>,
+  overrides?: Partial<
+    import("../../infra/outbound/session-binding-service.js").SessionBindingRecord
+  >,
 ) {
   return {
-    accountId: "default",
-    channelId: "parent-1",
-    threadId: "thread-1",
-    targetKind: "subagent",
+    bindingId: "default:thread-1",
     targetSessionKey: "agent:main:subagent:child-1",
-    agentId: "main",
-    boundBy: "test",
+    targetKind: "subagent",
+    conversation: {
+      channel: "discord",
+      accountId: "default",
+      conversationId: "thread-1",
+      parentConversationId: "parent-1",
+    },
+    status: "active",
     boundAt: 1,
-    webhookId: "wh-1",
-    webhookToken: "tok-1",
+    metadata: {
+      agentId: "main",
+      boundBy: "test",
+      webhookId: "wh-1",
+      webhookToken: "tok-1",
+    },
     ...overrides,
-  } satisfies import("./thread-bindings.js").ThreadBindingRecord;
+  } satisfies import("../../infra/outbound/session-binding-service.js").SessionBindingRecord;
 }
 
 describe("resolvePreflightMentionRequirement", () => {
@@ -58,6 +72,10 @@ describe("resolvePreflightMentionRequirement", () => {
 });
 
 describe("preflightDiscordMessage", () => {
+  beforeEach(() => {
+    sessionBindingTesting.resetSessionBindingAdaptersForTests();
+  });
+
   it("bypasses mention gating in bound threads for allowed bot senders", async () => {
     const threadBinding = createThreadBinding();
     const threadId = "thread-bot-focus";
@@ -99,6 +117,13 @@ describe("preflightDiscordMessage", () => {
       },
     } as unknown as import("@buape/carbon").Message;
 
+    registerSessionBindingAdapter({
+      channel: "discord",
+      accountId: "default",
+      listBySession: () => [],
+      resolveByConversation: (ref) => (ref.conversationId === threadId ? threadBinding : null),
+    });
+
     const result = await preflightDiscordMessage({
       cfg: {
         session: {
@@ -122,9 +147,7 @@ describe("preflightDiscordMessage", () => {
       groupDmEnabled: true,
       ackReactionScope: "direct",
       groupPolicy: "open",
-      threadBindings: {
-        getByThreadId: (id: string) => (id === threadId ? threadBinding : undefined),
-      } as import("./thread-bindings.js").ThreadBindingManager,
+      threadBindings: createNoopThreadBindingManager("default"),
       data: {
         channel_id: threadId,
         guild_id: "guild-1",
@@ -146,6 +169,7 @@ describe("preflightDiscordMessage", () => {
 
 describe("shouldIgnoreBoundThreadWebhookMessage", () => {
   beforeEach(() => {
+    sessionBindingTesting.resetSessionBindingAdaptersForTests();
     threadBindingTesting.resetThreadBindingsForTests();
   });
 
@@ -171,7 +195,11 @@ describe("shouldIgnoreBoundThreadWebhookMessage", () => {
     expect(
       shouldIgnoreBoundThreadWebhookMessage({
         webhookId: "wh-1",
-        threadBinding: createThreadBinding({ webhookId: undefined }),
+        threadBinding: createThreadBinding({
+          metadata: {
+            webhookId: undefined,
+          },
+        }),
       }),
     ).toBe(false);
   });