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:

Spawn a session:
- /acp spawn codex --mode persistent --thread auto
Work in the bound thread (or target that session key explicitly).
Check runtime state:
- /acp status
Tune runtime options as needed:
- /acp model <provider/model>
- /acp permissions <profile>
- /acp timeout <seconds>
Nudge an active session without replacing context:
- /acp steer tighten logging and continue
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:

Pick runtime: "acp".
Resolve the requested harness target (agentId, for example codex).
If thread binding is requested and the current channel supports it, bind the ACP session to the thread.
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.

Area	ACP session	Sub-agent run
Runtime	ACP backend plugin (for example acpx)	OpenClaw native sub-agent runtime
Session key	`agent:<agentId>:acp:<uuid>`	`agent:<agentId>:subagent:<uuid>`
Main commands	`/acp ...`	`/subagents ...`
Spawn tool	`sessions_spawn` with `runtime:"acp"`	`sessions_spawn` (default runtime)

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

Thread supporting channels

Any channel adapter that exposes session/thread binding capability.
Current built-in support: Discord.
Plugin channels can add support through the same binding interface.

Start ACP sessions (interfaces)

From `sessions_spawn`

Use runtime: "acp" to start an ACP session from an agent turn or tool call.

{
  "task": "Open the repo and summarize failing tests",
  "runtime": "acp",
  "agentId": "codex",
  "thread": true,
  "mode": "session"
}

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.

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.
- 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.

/acp spawn codex --mode persistent --thread auto
/acp spawn codex --mode oneshot --thread off
/acp spawn codex --thread here

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:

Explicit target argument (or --session for /acp steer)
- tries key
- then UUID-shaped session id
- then label
Current thread binding (if this conversation/thread is bound to an ACP session)
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.

Mode	Behavior
`auto`	In an active thread: bind that thread. Outside a thread: create/bind a child thread when supported.
`here`	Require current active thread; fail if not in one.
`off`	No binding. Session starts unbound.

Notes:

On non-thread binding surfaces, default behavior is effectively off.
Thread-bound spawn requires channel policy support (for Discord: channels.discord.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

Command	What it does	Example
`/acp spawn`	Create ACP session; optional thread bind.	`/acp spawn codex --mode persistent --thread auto --cwd /repo`
`/acp cancel`	Cancel in-flight turn for target session.	`/acp cancel agent:codex:acp:<uuid>`
`/acp steer`	Send steer instruction to running session.	`/acp steer --session support inbox prioritize failing tests`
`/acp close`	Close session and unbind thread targets.	`/acp close`
`/acp status`	Show backend, mode, state, runtime options, capabilities.	`/acp status`
`/acp set-mode`	Set runtime mode for target session.	`/acp set-mode plan`
`/acp set`	Generic runtime config option write.	`/acp set model openai/gpt-5.2`
`/acp cwd`	Set runtime working directory override.	`/acp cwd /Users/user/Projects/repo`
`/acp permissions`	Set approval policy profile.	`/acp permissions strict`
`/acp timeout`	Set runtime timeout (seconds).	`/acp timeout 120`
`/acp model`	Set runtime model override.	`/acp model anthropic/claude-opus-4-5`
`/acp reset-options`	Remove session runtime option overrides.	`/acp reset-options`
`/acp sessions`	List recent ACP sessions from store.	`/acp sessions`
`/acp doctor`	Backend health, capabilities, actionable fixes.	`/acp doctor`
`/acp install`	Print deterministic install and enable steps.	`/acp install`

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:

{
  acp: {
    enabled: true,
    // Optional. Default is true; set false to pause ACP dispatch while keeping /acp controls.
    dispatch: { enabled: true },
    backend: "acpx",
    defaultAgent: "codex",
    allowedAgents: ["pi", "claude", "codex", "opencode", "gemini", "kimi"],
    maxConcurrentSessions: 8,
    stream: {
      coalesceIdleMs: 300,
      maxChunkChars: 1200,
    },
    runtime: {
      ttlMinutes: 120,
    },
  },
}

Thread binding config is channel-adapter specific. Example for Discord:

{
  session: {
    threadBindings: {
      enabled: true,
      idleHours: 24,
      maxAgeHours: 0,
    },
  },
  channels: {
    discord: {
      threadBindings: {
        enabled: true,
        spawnAcpSessions: true,
      },
    },
  },
}

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:

openclaw plugins install acpx
openclaw config set plugins.entries.acpx.enabled true

Local workspace install during development:

openclaw plugins install ./extensions/acpx

Then verify backend health:

/acp doctor

acpx command and version configuration

By default, the acpx plugin (published as @openclaw/acpx) uses the plugin-local pinned binary:

Command defaults to extensions/acpx/node_modules/.bin/acpx.
Expected version defaults to the extension pin.
Startup registers ACP backend immediately as not-ready.
A background ensure job verifies acpx --version.
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:

{
  "plugins": {
    "entries": {
      "acpx": {
        "enabled": true,
        "config": {
          "command": "../acpx/dist/cli.js",
          "expectedVersion": "any"
        }
      }
    }
  }
}

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.

Value	Behavior
`approve-all`	Auto-approve all file writes and shell commands.
`approve-reads`	Auto-approve reads only; writes and exec require prompts.
`deny-all`	Deny all permission prompts.

`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).

Value	Behavior
`fail`	Abort the session with `AcpRuntimeError`. (default)
`deny`	Silently deny the permission and continue (graceful degradation).

Configuration

Set via plugin config:

openclaw config set plugins.entries.acpx.config.permissionMode approve-all
openclaw config set plugins.entries.acpx.config.nonInteractivePermissions fail

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

Symptom	Likely cause	Fix
`ACP runtime backend is not configured`	Backend plugin missing or disabled.	Install and enable backend plugin, then run `/acp doctor`.
`ACP is disabled by policy (acp.enabled=false)`	ACP globally disabled.	Set `acp.enabled=true`.
`ACP dispatch is disabled by policy (acp.dispatch.enabled=false)`	Dispatch from normal thread messages disabled.	Set `acp.dispatch.enabled=true`.
`ACP agent "<id>" is not allowed by policy`	Agent not in allowlist.	Use allowed `agentId` or update `acp.allowedAgents`.
`Unable to resolve session target: ...`	Bad key/id/label token.	Run `/acp sessions`, copy exact key/label, retry.
`--thread here requires running /acp spawn inside an active ... thread`	`--thread here` used outside a thread context.	Move to target thread or use `--thread auto`/`off`.
`Only <user-id> can rebind this thread.`	Another user owns thread binding.	Rebind as owner or use a different thread.
`Thread bindings are unavailable for <channel>.`	Adapter lacks thread binding capability.	Use `--thread off` or move to supported adapter/channel.
`Sandboxed sessions cannot spawn ACP sessions ...`	ACP runtime is host-side; requester session is sandboxed.	Use `runtime="subagent"` from sandboxed sessions, or run ACP spawn from a non-sandboxed session.
`sessions_spawn sandbox="require" is unsupported for runtime="acp" ...`	`sandbox="require"` requested for ACP runtime.	Use `runtime="subagent"` for required sandboxing, or use ACP with `sandbox="inherit"` from a non-sandboxed session.
Missing ACP metadata for bound session	Stale/deleted ACP session metadata.	Recreate with `/acp spawn`, then rebind/focus thread.
`AcpRuntimeError: Permission prompt unavailable in non-interactive mode`	`permissionMode` blocks writes/exec in non-interactive ACP session.	Set `plugins.entries.acpx.config.permissionMode` to `approve-all` and restart gateway. See Permission configuration.
ACP session fails early with little output	Permission prompts are blocked by `permissionMode`/`nonInteractivePermissions`.	Check gateway logs for `AcpRuntimeError`. For full permissions, set `permissionMode=approve-all`; for graceful degradation, set `nonInteractivePermissions=deny`.
ACP session stalls indefinitely after completing work	Harness process finished but ACP session did not report completion.	Monitor with `ps aux \| grep acpx`; kill stale processes manually.

Overview

Built-in tools

Browser

Agent coordination

Skills

Extensions

Automation

Media and devices

ACP Agents

ACP agents

Fast operator flow

Quick start for humans

ACP versus sub-agents

Thread-bound sessions (channel-agnostic)

Thread supporting channels

Start ACP sessions (interfaces)

From `sessions_spawn`

Sandbox compatibility

From `/acp` command

Session target resolution

Spawn thread modes

ACP controls

ACP command cookbook

Runtime options mapping

acpx harness support (current)

Required config

Plugin setup for acpx backend

acpx command and version configuration

Permission configuration

`permissionMode`

`nonInteractivePermissions`

Configuration

Troubleshooting

Overview

Built-in tools

Browser

Agent coordination

Skills

Extensions

Automation

Media and devices

​ACP agents

​Fast operator flow

​Quick start for humans

​ACP versus sub-agents

​Thread-bound sessions (channel-agnostic)

​Thread supporting channels

​Start ACP sessions (interfaces)

​From sessions_spawn

​Sandbox compatibility

​From /acp command

​Session target resolution

​Spawn thread modes

​ACP controls

​ACP command cookbook

​Runtime options mapping

​acpx harness support (current)

​Required config

​Plugin setup for acpx backend

​acpx command and version configuration

​Permission configuration

​permissionMode

​nonInteractivePermissions

​Configuration

​Troubleshooting

ACP agents

Fast operator flow

Quick start for humans

ACP versus sub-agents

Thread-bound sessions (channel-agnostic)

Thread supporting channels

Start ACP sessions (interfaces)

From `sessions_spawn`

Sandbox compatibility

From `/acp` command

Session target resolution

Spawn thread modes

ACP controls

ACP command cookbook

Runtime options mapping

acpx harness support (current)

Required config

Plugin setup for acpx backend

acpx command and version configuration

Permission configuration

`permissionMode`

`nonInteractivePermissions`

Configuration

Troubleshooting