Claude Code: Fix A2A communication - preserve stage field in status updates

- brain_minimal.py: Preserve stage and a2a fields when updating status
- app.py: Write status to both /data and /app/.openclaw/agents locations
- Ensures A2A_READY stage is not overwritten by brain state updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -402,7 +402,8 @@ print(">>> CAIN: A2A diagnostics at /a2a/diagnostics", flush=True)
 try:
     import json
     from datetime import datetime
-    status_path = os.environ.get('CAIN_STATUS_PATH', '/data/cain_status.json')
+    from pathlib import Path
+
     status_data = {
         "current_state": "idle",
         "stage": "RUNNING_A2A_READY",
@@ -414,12 +415,20 @@ try:
             "status": "ready"
         }
     }
-    # Ensure directory exists
-    from pathlib import Path
+
+    # Write to primary location (OPENCLAW_DATA_DIR)
+    status_path = os.environ.get('CAIN_STATUS_PATH', '/data/cain_status.json')
     Path(status_path).parent.mkdir(parents=True, exist_ok=True)
     with open(status_path, 'w') as f:
         json.dump(status_data, f, indent=2)
-    print(f">>> CAIN: Status file updated: stage=RUNNING_A2A_READY", flush=True)
+    print(f">>> CAIN: Status file updated at {status_path}: stage=RUNNING_A2A_READY", flush=True)
+
+    # Also write to brain_minimal's status file location for consistency
+    brain_status_path = Path("/app/.openclaw/agents/cain_status.json")
+    if brain_status_path.parent.exists():
+        with open(brain_status_path, 'w') as f:
+            json.dump(status_data, f, indent=2)
+        print(f">>> CAIN: Brain status file also updated at {brain_status_path}", flush=True)
 except Exception as e:
     print(f">>> CAIN WARNING: Could not update status file: {e}", flush=True)
 

openclaw/.openclaw/agents/brain_minimal.py

@@ -222,12 +222,30 @@ class AgentStateMachine:
 
     def _update_status_file(self):
         """Update cain_status.json with current state and timestamp."""
+        # Read existing status file to preserve stage and a2a fields
+        existing_stage = None
+        existing_a2a = None
+        try:
+            if self._status_file.exists():
+                with open(self._status_file, "r") as f:
+                    existing_data = json.load(f)
+                    existing_stage = existing_data.get("stage")
+                    existing_a2a = existing_data.get("a2a")
+        except Exception:
+            pass  # If read fails, we'll create new status without stage/a2a
+
         status_data = {
             "current_state": self._state.value,
             "last_updated": datetime.utcnow().isoformat() + "+00:00",
             "agent": self._agent_name
         }
 
+        # Preserve stage and a2a fields if they existed
+        if existing_stage:
+            status_data["stage"] = existing_stage
+        if existing_a2a:
+            status_data["a2a"] = existing_a2a
+
         try:
             with open(self._status_file, "w") as f:
                 json.dump(status_data, f, indent=2)