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.ts

@@ -17,6 +17,10 @@ import { loadConfig } from "../../config/config.js";
 import { isDangerousNameMatchingEnabled } from "../../config/dangerous-name-matching.js";
 import { logVerbose, shouldLogVerbose } from "../../globals.js";
 import { recordChannelActivity } from "../../infra/channel-activity.js";
+import {
+  getSessionBindingService,
+  type SessionBindingRecord,
+} from "../../infra/outbound/session-binding-service.js";
 import { enqueueSystemEvent } from "../../infra/system-events.js";
 import { logDebug } from "../../logger.js";
 import { getChildLogger } from "../../logging.js";
@@ -57,10 +61,7 @@ import {
 } from "./message-utils.js";
 import { resolveDiscordSenderIdentity, resolveDiscordWebhookId } from "./sender-identity.js";
 import { resolveDiscordSystemEvent } from "./system-events.js";
-import {
-  isRecentlyUnboundThreadWebhookMessage,
-  type ThreadBindingRecord,
-} from "./thread-bindings.js";
+import { isRecentlyUnboundThreadWebhookMessage } from "./thread-bindings.js";
 import { resolveDiscordThreadChannel, resolveDiscordThreadParentInfo } from "./threading.js";
 
 export type {
@@ -82,13 +83,16 @@ export function shouldIgnoreBoundThreadWebhookMessage(params: {
   accountId?: string;
   threadId?: string;
   webhookId?: string | null;
-  threadBinding?: ThreadBindingRecord;
+  threadBinding?: SessionBindingRecord;
 }): boolean {
   const webhookId = params.webhookId?.trim() || "";
   if (!webhookId) {
     return false;
   }
-  const boundWebhookId = params.threadBinding?.webhookId?.trim() || "";
+  const boundWebhookId =
+    typeof params.threadBinding?.metadata?.webhookId === "string"
+      ? params.threadBinding.metadata.webhookId.trim()
+      : "";
   if (!boundWebhookId) {
     const threadId = params.threadId?.trim() || "";
     if (!threadId) {
@@ -296,9 +300,15 @@ export async function preflightDiscordMessage(
     // Pass parent peer for thread binding inheritance
     parentPeer: earlyThreadParentId ? { kind: "channel", id: earlyThreadParentId } : undefined,
   });
-  const threadBinding = earlyThreadChannel
-    ? params.threadBindings.getByThreadId(messageChannelId)
-    : undefined;
+  let threadBinding: SessionBindingRecord | undefined;
+  if (earlyThreadChannel) {
+    threadBinding =
+      getSessionBindingService().resolveByConversation({
+        channel: "discord",
+        accountId: params.accountId,
+        conversationId: messageChannelId,
+      }) ?? undefined;
+  }
   if (
     shouldIgnoreBoundThreadWebhookMessage({
       accountId: params.accountId,