# ACP agents sessions

> Start ACP sessions from sessionsspawn or /acp spawn, with the parameter and mode reference

- 网址：https://funcoding.ai/agents/openclaw/tools/acp-agents/sessions/
- 来源：OpenClaw 官方文档原文（英文），MIT 许可，同步于 2026-10-11
- 官方原文：https://docs.openclaw.ai/zh-CN/tools/acp-agents/sessions

---
## Start ACP sessions

Two ways to start an ACP session:

**From sessions_spawn**

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

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

<div class="callout callout-note">

`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.

</div>

**From /acp command**

Use `/acp spawn` for explicit operator control from chat.

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

Key flags:

- `--mode persistent|oneshot`
- `--bind here|off`
- `--thread auto|here|off`
- `--cwd <absolute-path>`
- `--label <name>`

See [Slash commands](https://funcoding.ai/agents/openclaw/tools/slash-commands/).

### `sessions_spawn` parameters

The person's requester_profile.id, required when several people have steered this turn.

Initial prompt sent to the ACP session.

Must be `"acp"` for ACP sessions.

ACP target harness id or configured ACP agent alias. Falls back to
`acp.defaultAgent` if set. Raw harnesses create children under the requesting
OpenClaw agent; configured aliases own their children. The harness remains
the ACP runtime identity in either case.
For cross-agent aliases, thread binding and inline delivery use the owner's bound channel account.
A raw harness keeps the requesting agent's active inbound account.

Request thread binding flow where supported.

`"run"` is one-shot; `"session"` is persistent. If `thread: true` and
`mode` is omitted, OpenClaw may default to persistent behaviour per
runtime path. `mode: "session"` requires `thread: true`.

Requested runtime working directory (validated by backend/runtime policy).
If omitted, ACP spawn inherits the OpenClaw owner's workspace when configured;
missing inherited paths fall back to backend defaults, while real access
errors are returned.

Operator-facing label used in session/banner text.

Resume an existing ACP session instead of creating a new one. The agent
replays its conversation history via `session/load`. Requires
`runtime: "acp"`. The ID must be recorded for the selected backend and harness and belong
to the requester (the requester itself or a session it spawned or parented).
Unknown IDs are rejected without enumerating the agent's sessions.
Historical harness-owned records remain eligible under the same checks;
spawning does not move or rewrite their histories. OpenClaw checks ownership
again before initializing the resumed runtime.

`"parent"` streams initial ACP run progress summaries back to the requester
session as system events. OpenClaw records the full relay history in the
child agent's SQLite state and removes it with the child session. Parent
progress streams show assistant commentary and ACP status progress by default unless
`streaming.progress.commentary=false`. Discord parent progress requires an
explicit `streaming.mode: "progress"`; unset Discord streaming stays quiet.
Status progress still honors `acp.stream.tagVisibility`, so tags such as
`plan` remain hidden unless explicitly enabled.

ACP `sessions_spawn` runs use `agents.defaults.subagents.runTimeoutSeconds`
for their default child turn limit. The tool does not accept per-call
timeout overrides (`runTimeoutSeconds`/`timeoutSeconds` are rejected with a
config-the-default error).

Explicit model override for the ACP child session. Codex ACP spawns
normalize OpenAI refs such as `openai/gpt-5.4` to Codex ACP startup config
before `session/new`; slash forms such as `openai/gpt-5.4/high` also set
Codex ACP reasoning effort. When omitted, `sessions_spawn({ runtime: "acp" })`
uses the target agent's `subagents.model`, then `agents.defaults.subagents.model`,
then the target agent's explicit `model.primary`. If none is configured, it lets
the ACP harness use its own default model. Native subagent spawns do not inherit
an ACP agent's harness primary; they use native subagent settings or the native
default instead. Other harnesses must advertise ACP model
controls for an explicit selection. Without those controls, an explicit
selection fails; an inherited default may be omitted so the harness can use
its own default.

Explicit thinking/reasoning effort. For Codex ACP, `minimal` maps to low
effort, `low`/`medium`/`high`/`xhigh` map directly, and `off` omits the
reasoning-effort startup override. An explicit value takes precedence over
a reasoning suffix in `model`, including `off`. When omitted, ACP spawns use existing
subagent thinking defaults, the configured target agent's `thinkingDefault`, and per-model
`params.thinking` for the selected model. The target agent's
`agents.entries.<agent>.models["provider/model"]` setting overrides the shared
`agents.defaults.models["provider/model"]` setting.

## Spawn bind and thread modes

**--bind here|off**

| Mode   | Behavior                                                               |
| ------ | ----------------------------------------------------------------------- |
| `here` | Bind the current active conversation in place; fail if none is active. |
| `off`  | Do not create a current-conversation binding.                          |

Notes:

- `--bind here` is the simplest operator path for "make this channel or chat Codex-backed."
- `--bind here` does not create a child thread.
- `--bind here` is only available on channels that expose current-conversation binding support.
- `--bind` and `--thread` cannot be combined in the same `/acp spawn` call.

**--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:
  - Discord/Telegram: `session.threadBindings.spawnSessions=true`
- Use `--bind here` when you want to pin the current conversation without creating a child thread.