feat(skill): add n8n action-bus helper

skills/n8n-webhook/references/payloads.md

@@ -25,52 +25,88 @@ Recommended success response:
 }
 ```
 
-## Recommended contract for new endpoints
+## Preferred router endpoint
 
-Prefer a stable JSON shape like:
+### `openclaw-action`
+
+Purpose:
+- keep the external n8n surface small
+- route several agent-safe operations behind one authenticated webhook
+
+Recommended request shape:
+
+```json
+{
+  "action": "append_log",
+  "args": {
+    "text": "backup complete"
+  },
+  "request_id": "optional-uuid"
+}
+```
+
+Recommended success response:
 
 ```json
 {
   "ok": true,
   "request_id": "optional-uuid",
   "result": {
-    "...": "workflow-specific payload"
+    "status": "accepted"
   }
 }
 ```
 
-On failure, return a non-2xx status plus:
+Recommended failure response:
 
 ```json
 {
   "ok": false,
   "error": {
-    "code": "short-machine-code",
-    "message": "human-readable summary"
+    "code": "unknown_action",
+    "message": "action is not supported"
   }
 }
 ```
 
-## Naming guidance
+## Suggested initial actions
 
-- Use lowercase kebab-case webhook paths.
-- Keep names explicit: `openclaw-ping`, `openclaw-action`, `append-log`, `send-notify`.
-- Avoid generic names like `run`, `task`, or `webhook1`.
+### `append_log`
 
-## Suggested action-bus pattern
-
-If multiple agent-safe actions are needed, prefer one router webhook such as `openclaw-action`.
-
-Request shape:
+Request:
 
 ```json
 {
   "action": "append_log",
   "args": {
-    "text": "backup finished"
-  },
-  "request_id": "optional-uuid"
+    "text": "backup complete"
+  }
 }
 ```
 
-That keeps the external surface small while letting n8n route internally.
+Purpose:
+- append a short line to a known log or tracking sink
+
+### `notify`
+
+Request:
+
+```json
+{
+  "action": "notify",
+  "args": {
+    "message": "workflow finished",
+    "title": "optional title"
+  }
+}
+```
+
+Purpose:
+- send a small notification through a known downstream channel
+
+## Naming guidance
+
+- Use lowercase kebab-case for webhook paths.
+- Use lowercase snake_case or kebab-case consistently for action names; prefer snake_case for JSON actions if using switch/router logic.
+- Keep names explicit: `openclaw-ping`, `openclaw-action`, `append_log`, `notify`.
+- Avoid generic names like `run`, `task`, or `webhook1`.