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/agents/system-prompt.ts

@@ -209,6 +209,8 @@ export function buildAgentSystemPrompt(params: {
   ttsHint?: string;
   /** Controls which hardcoded sections to include. Defaults to "full". */
   promptMode?: PromptMode;
+  /** Whether ACP-specific routing guidance should be included. Defaults to true. */
+  acpEnabled?: boolean;
   runtimeInfo?: {
     agentId?: string;
     host?: string;
@@ -231,6 +233,7 @@ export function buildAgentSystemPrompt(params: {
   };
   memoryCitationsMode?: MemoryCitationsMode;
 }) {
+  const acpEnabled = params.acpEnabled !== false;
   const coreToolSummaries: Record<string, string> = {
     read: "Read file contents",
     write: "Create or overwrite files",
@@ -250,11 +253,15 @@ export function buildAgentSystemPrompt(params: {
     cron: "Manage cron jobs and wake events (use for reminders; when scheduling a reminder, write the systemEvent text as something that will read like a reminder when it fires, and mention that it is a reminder depending on the time gap between setting and firing; include recent context in reminder text if appropriate)",
     message: "Send messages and channel actions",
     gateway: "Restart, apply config, or run updates on the running OpenClaw process",
-    agents_list: "List agent ids allowed for sessions_spawn",
+    agents_list: acpEnabled
+      ? 'List OpenClaw agent ids allowed for sessions_spawn when runtime="subagent" (not ACP harness ids)'
+      : "List OpenClaw agent ids allowed for sessions_spawn",
     sessions_list: "List other sessions (incl. sub-agents) with filters/last",
     sessions_history: "Fetch history for another session/sub-agent",
     sessions_send: "Send a message to another session/sub-agent",
-    sessions_spawn: "Spawn a sub-agent session",
+    sessions_spawn: acpEnabled
+      ? 'Spawn an isolated sub-agent or ACP coding session (runtime="acp" requires `agentId` unless `acp.defaultAgent` is configured; ACP harness ids follow acp.allowedAgents, not agents_list)'
+      : "Spawn an isolated sub-agent session",
     subagents: "List, steer, or kill sub-agent runs for this requester session",
     session_status:
       "Show a /status-equivalent status card (usage + time + Reasoning/Verbose/Elevated); use for model-use questions (📊 session_status); optional per-session model override",
@@ -303,6 +310,7 @@ export function buildAgentSystemPrompt(params: {
 
   const normalizedTools = canonicalToolNames.map((tool) => tool.toLowerCase());
   const availableTools = new Set(normalizedTools);
+  const hasSessionsSpawn = availableTools.has("sessions_spawn");
   const externalToolSummaries = new Map<string, string>();
   for (const [key, value] of Object.entries(params.toolSummaries ?? {})) {
     const normalized = key.trim().toLowerCase();
@@ -436,6 +444,13 @@ export function buildAgentSystemPrompt(params: {
     "TOOLS.md does not control tool availability; it is user guidance for how to use external tools.",
     `For long waits, avoid rapid poll loops: use ${execToolName} with enough yieldMs or ${processToolName}(action=poll, timeout=<ms>).`,
     "If a task is more complex or takes longer, spawn a sub-agent. Completion is push-based: it will auto-announce when done.",
+    ...(hasSessionsSpawn && acpEnabled
+      ? [
+          'For requests like "do this in codex/claude code/gemini", treat it as ACP harness intent and call `sessions_spawn` with `runtime: "acp"`.',
+          'On Discord, default ACP harness requests to thread-bound persistent sessions (`thread: true`, `mode: "session"`) unless the user asks otherwise.',
+          "Set `agentId` explicitly unless `acp.defaultAgent` is configured, and do not route ACP harness requests through `subagents`/`agents_list` or local PTY exec flows.",
+        ]
+      : []),
     "Do not poll `subagents list` / `sessions_list` in a loop; only check status on-demand (for intervention, debugging, or when explicitly asked).",
     "",
     "## Tool Call Style",
@@ -443,6 +458,7 @@ export function buildAgentSystemPrompt(params: {
     "Narrate only when it helps: multi-step work, complex/challenging problems, sensitive actions (e.g., deletions), or when the user explicitly asks.",
     "Keep narration brief and value-dense; avoid repeating obvious steps.",
     "Use plain human language for narration unless in a technical context.",
+    "When a first-class tool exists for an action, use the tool directly instead of asking the user to run equivalent CLI or slash commands.",
     "",
     ...safetySection,
     "## OpenClaw CLI Quick Reference",