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ACP agents

Agent Client Protocol (ACP) sessions let OpenClaw run external coding harnesses (for example Pi, Claude Code, Codex, OpenCode, and Gemini CLI) through an ACP backend plugin. If you ask OpenClaw in plain language to “run this in Codex” or “start Claude Code in a thread”, OpenClaw should route that request to the ACP runtime (not the native sub-agent runtime).

Fast operator flow

Use this when you want a practical /acp runbook:
  1. Spawn a session:
    • /acp spawn codex --mode persistent --thread auto
  2. Work in the bound thread (or target that session key explicitly).
  3. Check runtime state:
    • /acp status
  4. Tune runtime options as needed:
    • /acp model <provider/model>
    • /acp permissions <profile>
    • /acp timeout <seconds>
  5. Nudge an active session without replacing context:
    • /acp steer tighten logging and continue
  6. Stop work:
    • /acp cancel (stop current turn), or
    • /acp close (close session + remove bindings)

Quick start for humans

Examples of natural requests:
  • “Start a persistent Codex session in a thread here and keep it focused.”
  • “Run this as a one-shot Claude Code ACP session and summarize the result.”
  • “Use Gemini CLI for this task in a thread, then keep follow-ups in that same thread.”
What OpenClaw should do:
  1. Pick runtime: "acp".
  2. Resolve the requested harness target (agentId, for example codex).
  3. If thread binding is requested and the current channel supports it, bind the ACP session to the thread.
  4. Route follow-up thread messages to that same ACP session until unfocused/closed/expired.

ACP versus sub-agents

Use ACP when you want an external harness runtime. Use sub-agents when you want OpenClaw-native delegated runs. See also Sub-agents.

Thread-bound sessions (channel-agnostic)

When thread bindings are enabled for a channel adapter, ACP sessions can be bound to threads:
  • OpenClaw binds a thread to a target ACP session.
  • Follow-up messages in that thread route to the bound ACP session.
  • ACP output is delivered back to the same thread.
  • Unfocus/close/archive/idle-timeout or max-age expiry removes the binding.
Thread binding support is adapter-specific. If the active channel adapter does not support thread bindings, OpenClaw returns a clear unsupported/unavailable message. Required feature flags for thread-bound ACP:
  • acp.enabled=true
  • acp.dispatch.enabled is on by default (set false to pause ACP dispatch)
  • Channel-adapter ACP thread-spawn flag enabled (adapter-specific)
    • Discord: channels.discord.threadBindings.spawnAcpSessions=true
    • Telegram: channels.telegram.threadBindings.spawnAcpSessions=true

Thread supporting channels

  • Any channel adapter that exposes session/thread binding capability.
  • Current built-in support:
    • Discord threads/channels
    • Telegram topics (forum topics in groups/supergroups and DM topics)
  • Plugin channels can add support through the same binding interface.

Channel specific settings

For non-ephemeral workflows, configure persistent ACP bindings in top-level bindings[] entries.

Binding model

  • bindings[].type="acp" marks a persistent ACP conversation binding.
  • bindings[].match identifies the target conversation:
    • Discord channel or thread: match.channel="discord" + match.peer.id="<channelOrThreadId>"
    • Telegram forum topic: match.channel="telegram" + match.peer.id="<chatId>:topic:<topicId>"
  • bindings[].agentId is the owning OpenClaw agent id.
  • Optional ACP overrides live under bindings[].acp:
    • mode (persistent or oneshot)
    • label
    • cwd
    • backend

Runtime defaults per agent

Use agents.list[].runtime to define ACP defaults once per agent:
  • agents.list[].runtime.type="acp"
  • agents.list[].runtime.acp.agent (harness id, for example codex or claude)
  • agents.list[].runtime.acp.backend
  • agents.list[].runtime.acp.mode
  • agents.list[].runtime.acp.cwd
Override precedence for ACP bound sessions:
  1. bindings[].acp.*
  2. agents.list[].runtime.acp.*
  3. global ACP defaults (for example acp.backend)
Example:
Behavior:
  • OpenClaw ensures the configured ACP session exists before use.
  • Messages in that channel or topic route to the configured ACP session.
  • In bound conversations, /new and /reset reset the same ACP session key in place.
  • Temporary runtime bindings (for example created by thread-focus flows) still apply where present.

Start ACP sessions (interfaces)

From sessions_spawn

Use runtime: "acp" to start an ACP session from an agent turn or tool call.
Notes:
  • runtime defaults to subagent, so set runtime: "acp" explicitly for ACP sessions.
  • If agentId is omitted, OpenClaw uses acp.defaultAgent when configured.
  • mode: "session" requires thread: true to keep a persistent bound conversation.
Interface details:
  • task (required): initial prompt sent to the ACP session.
  • runtime (required for ACP): must be "acp".
  • agentId (optional): ACP target harness id. Falls back to acp.defaultAgent if set.
  • thread (optional, default false): request thread binding flow where supported.
  • mode (optional): run (one-shot) or session (persistent).
    • default is run
    • if thread: true and mode omitted, OpenClaw may default to persistent behavior per runtime path
    • mode: "session" requires thread: true
  • cwd (optional): requested runtime working directory (validated by backend/runtime policy).
  • label (optional): operator-facing label used in session/banner text.
  • streamTo (optional): "parent" streams initial ACP run progress summaries back to the requester session as system events.
    • When available, accepted responses include streamLogPath pointing to a session-scoped JSONL log (<sessionId>.acp-stream.jsonl) you can tail for full relay history.

Operator smoke test

Use this after a gateway deploy when you want a quick live check that ACP spawn is actually working end-to-end, not just passing unit tests. Recommended gate:
  1. Verify the deployed gateway version/commit on the target host.
  2. Confirm the deployed source includes the ACP lineage acceptance in src/gateway/sessions-patch.ts (subagent:* or acp:* sessions).
  3. Open a temporary ACPX bridge session to a live agent (for example razor(main) on jpclawhq).
  4. Ask that agent to call sessions_spawn with:
    • runtime: "acp"
    • agentId: "codex"
    • mode: "run"
    • task: Reply with exactly LIVE-ACP-SPAWN-OK
  5. Verify the agent reports:
    • accepted=yes
    • a real childSessionKey
    • no validator error
  6. Clean up the temporary ACPX bridge session.
Example prompt to the live agent:
Notes:
  • Keep this smoke test on mode: "run" unless you are intentionally testing thread-bound persistent ACP sessions.
  • Do not require streamTo: "parent" for the basic gate. That path depends on requester/session capabilities and is a separate integration check.
  • Treat thread-bound mode: "session" testing as a second, richer integration pass from a real Discord thread or Telegram topic.

Sandbox compatibility

ACP sessions currently run on the host runtime, not inside the OpenClaw sandbox. Current limitations:
  • If the requester session is sandboxed, ACP spawns are blocked for both sessions_spawn({ runtime: "acp" }) and /acp spawn.
    • Error: Sandboxed sessions cannot spawn ACP sessions because runtime="acp" runs on the host. Use runtime="subagent" from sandboxed sessions.
  • sessions_spawn with runtime: "acp" does not support sandbox: "require".
    • Error: sessions_spawn sandbox="require" is unsupported for runtime="acp" because ACP sessions run outside the sandbox. Use runtime="subagent" or sandbox="inherit".
Use runtime: "subagent" when you need sandbox-enforced execution.

From /acp command

Use /acp spawn for explicit operator control from chat when needed.
Key flags:
  • --mode persistent|oneshot
  • --thread auto|here|off
  • --cwd <absolute-path>
  • --label <name>
See Slash Commands.

Session target resolution

Most /acp actions accept an optional session target (session-key, session-id, or session-label). Resolution order:
  1. Explicit target argument (or --session for /acp steer)
    • tries key
    • then UUID-shaped session id
    • then label
  2. Current thread binding (if this conversation/thread is bound to an ACP session)
  3. Current requester session fallback
If no target resolves, OpenClaw returns a clear error (Unable to resolve session target: ...).

Spawn thread modes

/acp spawn supports --thread auto|here|off. Notes:
  • On non-thread binding surfaces, default behavior is effectively off.
  • Thread-bound spawn requires channel policy support:
    • Discord: channels.discord.threadBindings.spawnAcpSessions=true
    • Telegram: channels.telegram.threadBindings.spawnAcpSessions=true

ACP controls

Available command family:
  • /acp spawn
  • /acp cancel
  • /acp steer
  • /acp close
  • /acp status
  • /acp set-mode
  • /acp set
  • /acp cwd
  • /acp permissions
  • /acp timeout
  • /acp model
  • /acp reset-options
  • /acp sessions
  • /acp doctor
  • /acp install
/acp status shows the effective runtime options and, when available, both runtime-level and backend-level session identifiers. Some controls depend on backend capabilities. If a backend does not support a control, OpenClaw returns a clear unsupported-control error.

ACP command cookbook

Runtime options mapping

/acp has convenience commands and a generic setter. Equivalent operations:
  • /acp model <id> maps to runtime config key model.
  • /acp permissions <profile> maps to runtime config key approval_policy.
  • /acp timeout <seconds> maps to runtime config key timeout.
  • /acp cwd <path> updates runtime cwd override directly.
  • /acp set <key> <value> is the generic path.
    • Special case: key=cwd uses the cwd override path.
  • /acp reset-options clears all runtime overrides for target session.

acpx harness support (current)

Current acpx built-in harness aliases:
  • pi
  • claude
  • codex
  • opencode
  • gemini
  • kimi
When OpenClaw uses the acpx backend, prefer these values for agentId unless your acpx config defines custom agent aliases. Direct acpx CLI usage can also target arbitrary adapters via --agent <command>, but that raw escape hatch is an acpx CLI feature (not the normal OpenClaw agentId path).

Required config

Core ACP baseline:
Thread binding config is channel-adapter specific. Example for Discord:
If thread-bound ACP spawn does not work, verify the adapter feature flag first:
  • Discord: channels.discord.threadBindings.spawnAcpSessions=true
See Configuration Reference.

Plugin setup for acpx backend

Install and enable plugin:
Local workspace install during development:
Then verify backend health:

acpx command and version configuration

By default, the acpx plugin (published as @openclaw/acpx) uses the plugin-local pinned binary:
  1. Command defaults to extensions/acpx/node_modules/.bin/acpx.
  2. Expected version defaults to the extension pin.
  3. Startup registers ACP backend immediately as not-ready.
  4. A background ensure job verifies acpx --version.
  5. If the plugin-local binary is missing or mismatched, it runs: npm install --omit=dev --no-save acpx@<pinned> and re-verifies.
You can override command/version in plugin config:
Notes:
  • command accepts an absolute path, relative path, or command name (acpx).
  • Relative paths resolve from OpenClaw workspace directory.
  • expectedVersion: "any" disables strict version matching.
  • When command points to a custom binary/path, plugin-local auto-install is disabled.
  • OpenClaw startup remains non-blocking while the backend health check runs.
See Plugins.

Permission configuration

ACP sessions run non-interactively — there is no TTY to approve or deny file-write and shell-exec permission prompts. The acpx plugin provides two config keys that control how permissions are handled:

permissionMode

Controls which operations the harness agent can perform without prompting.

nonInteractivePermissions

Controls what happens when a permission prompt would be shown but no interactive TTY is available (which is always the case for ACP sessions).

Configuration

Set via plugin config:
Restart the gateway after changing these values.
Important: OpenClaw currently defaults to permissionMode=approve-reads and nonInteractivePermissions=fail. In non-interactive ACP sessions, any write or exec that triggers a permission prompt can fail with AcpRuntimeError: Permission prompt unavailable in non-interactive mode. If you need to restrict permissions, set nonInteractivePermissions to deny so sessions degrade gracefully instead of crashing.

Troubleshooting