diff --git a/.openclaw-sync/source.json b/.openclaw-sync/source.json
index 78f6592da..253962e6e 100644
--- a/.openclaw-sync/source.json
+++ b/.openclaw-sync/source.json
@@ -1,5 +1,5 @@
 {
   "repository": "openclaw/openclaw",
-  "sha": "afabbc01b25f48d1a2753e91a7cd1d65185de2be",
-  "syncedAt": "2026-04-25T20:09:29.674Z"
+  "sha": "6a7b76e119caa401e9a9c304e612ef0d9453f93c",
+  "syncedAt": "2026-04-25T20:24:38.007Z"
 }
diff --git a/docs/tools/acp-agents.md b/docs/tools/acp-agents.md
index 478f602d6..4034f5d84 100644
--- a/docs/tools/acp-agents.md
+++ b/docs/tools/acp-agents.md
@@ -78,6 +78,13 @@ Natural-language triggers that should route to the ACP runtime:
 
 OpenClaw picks `runtime: "acp"`, resolves the harness `agentId`, binds to the current conversation or thread when supported, and routes follow-ups to that session until close/expiry. Codex only follows this path when ACP is explicit or the requested background runtime still needs ACP.
 
+For `sessions_spawn`, `runtime: "acp"` targets ACP harness ids such as `codex`,
+`claude`, `gemini`, or `opencode`. Do not pass a normal OpenClaw config agent
+id from `agents_list` unless that entry is explicitly configured with
+`agents.list[].runtime.type="acp"`; otherwise use the default sub-agent runtime.
+When an OpenClaw agent is configured with `runtime.type="acp"`, OpenClaw uses
+`runtime.acp.agent` as the underlying harness id.
+
 ## ACP versus sub-agents
 
 Use ACP when you want an external harness runtime. Use native Codex app-server for Codex conversation binding/control. Use sub-agents when you want OpenClaw-native delegated runs.
diff --git a/docs/tools/subagents.md b/docs/tools/subagents.md
index 2626aec13..520871aea 100644
--- a/docs/tools/subagents.md
+++ b/docs/tools/subagents.md
@@ -60,7 +60,7 @@ transcript path on disk when you need the raw full transcript.
 - `--model` and `--thinking` override defaults for that specific run.
 - Use `info`/`log` to inspect details and output after completion.
 - `/subagents spawn` is one-shot mode (`mode: "run"`). For persistent thread-bound sessions, use `sessions_spawn` with `thread: true` and `mode: "session"`.
-- For ACP harness sessions (Codex, Claude Code, Gemini CLI), use `sessions_spawn` with `runtime: "acp"` and see [ACP Agents](/tools/acp-agents), especially the [ACP delivery model](/tools/acp-agents#delivery-model) when debugging completions or agent-to-agent loops.
+- For ACP harness sessions (Codex, Claude Code, Gemini CLI, OpenCode), use `sessions_spawn` with `runtime: "acp"` and see [ACP Agents](/tools/acp-agents), especially the [ACP delivery model](/tools/acp-agents#delivery-model) when debugging completions or agent-to-agent loops. `runtime: "acp"` expects an external ACP harness id, or an `agents.list[]` entry with `runtime.type="acp"`; use the default sub-agent runtime for normal OpenClaw config agents from `agents_list`.
 
 Primary goals:
 
@@ -103,6 +103,7 @@ Tool params:
 - `task` (required)
 - `label?` (optional)
 - `agentId?` (optional; spawn under another agent id if allowed)
+- `runtime?` (`subagent|acp`, default `subagent`; `acp` is only for external ACP harnesses such as `codex`, `claude`, `gemini`, or `opencode`, or for `agents.list[]` entries whose `runtime.type` is `acp`)
 - `model?` (optional; overrides the sub-agent model; invalid values are skipped and the sub-agent runs on the default model with a warning in the tool result)
 - `thinking?` (optional; overrides thinking level for the sub-agent run)
 - `runTimeoutSeconds?` (defaults to `agents.defaults.subagents.runTimeoutSeconds` when set, otherwise `0`; when set, the sub-agent run is aborted after N seconds)