- `resumeSessionId` (optional): resume an existing ACP session instead of creating a new one. The agent replays its conversation history via `session/load`. Requires `runtime: "acp"`.

- `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.

- `model` (optional): explicit model override for the ACP child session. Honored for `runtime: "acp"` so the child uses the requested model instead of silently falling back to the target agent default. Codex ACP spawns normalize OpenClaw Codex refs such as `openai-codex/gpt-5.4` to Codex ACP startup config before `session/new`; slash forms such as `openai-codex/gpt-5.4/high` also set Codex ACP reasoning effort.

- `model` (optional): explicit model override for the ACP child session. Codex ACP spawns normalize OpenClaw Codex refs such as `openai-codex/gpt-5.4` to Codex ACP startup config before `session/new`; slash forms such as `openai-codex/gpt-5.4/high` also set Codex ACP reasoning effort. Other harnesses must advertise ACP `models` and support `session/set_model`; otherwise OpenClaw/acpx fails clearly instead of silently falling back to the target agent default.

- `thinking` (optional): explicit thinking/reasoning effort for the ACP child session. For Codex ACP, `minimal` maps to low effort, `low`/`medium`/`high`/`xhigh` map directly, and `off` omits the reasoning-effort startup override.

## Delivery model

Equivalent operations:

- `/acp model <id>` maps to runtime config key `model`. For Codex ACP, OpenClaw normalizes `openai-codex/<model>` to the adapter model id and maps slash reasoning suffixes such as `openai-codex/gpt-5.4/high` to Codex ACP `reasoning_effort`.

- `/acp model <id>` maps to runtime config key `model`. For Codex ACP, OpenClaw normalizes `openai-codex/<model>` to the adapter model id and maps slash reasoning suffixes such as `openai-codex/gpt-5.4/high` to Codex ACP `reasoning_effort`. For other harnesses, model control depends on adapter support for ACP `models` and `session/set_model`.

- `/acp set thinking <level>` maps to runtime config key `thinking`. For Codex ACP, OpenClaw sends the corresponding `reasoning_effort` where the adapter supports one.

- `/acp permissions <profile>` maps to runtime config key `approval_policy`.

- `/acp timeout <seconds>` maps to runtime config key `timeout`.

| `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. |

| `Cannot apply --model ... did not advertise model support` | The target harness does not expose generic ACP model switching. | Use a harness that advertises ACP `models`/`session/set_model`, use Codex ACP model refs, or configure the model directly in the harness if it has its own startup flag. |

| 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](/tools/acp-agents-setup#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`. |