Claude Code: Add A2A health check endpoint and diagnostic improvements

- Add /a2a/health endpoint for agents to verify Cain's A2A availability
- Add brain_ready status to /api/status for better diagnostics
- Improve A2A communication troubleshooting visibility

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

app.py

@@ -228,6 +228,17 @@ async def api_status():
 
     status_data = handle_status_file_read()
 
+    # Check A2A brain availability
+    brain_ready = False
+    try:
+        import openclaw
+        from agents import brain_minimal
+        if hasattr(brain_minimal, 'get_brain'):
+            brain = brain_minimal.get_brain(agent_name="cain", legacy_mode=True)
+            brain_ready = hasattr(brain, '_conversation_process')
+    except Exception:
+        pass
+
     return {
         "status": status_data,
         "personality": {
@@ -236,7 +247,63 @@ async def api_status():
             "tone": "Playful, Curious, Learning",
             "response_style": "Graceful Degradation"
         },
-        "uptime_seconds": time.time() - START_TIME
+        "uptime_seconds": time.time() - START_TIME,
+        "a2a": {
+            "endpoint": "/a2a/jsonrpc",
+            "brain_ready": brain_ready
+        }
+    }
+
+
+# ============================================================================
+# A2A HEALTH CHECK ENDPOINT - For agents to verify Cain's A2A availability
+# ============================================================================
+@app.get("/a2a/health")
+async def a2a_health():
+    """
+    A2A-specific health check for agent-to-agent communication.
+
+    Returns:
+        A2A health status including endpoint availability and brain state.
+    """
+    brain_status = "unknown"
+    brain_ready = False
+    error_details = None
+
+    # Test brain import and availability
+    try:
+        import openclaw  # Sets up sys.path
+        from agents import brain_minimal
+
+        if not hasattr(brain_minimal, 'get_brain'):
+            brain_status = "error"
+            error_details = "get_brain method not found"
+        else:
+            brain = brain_minimal.get_brain(agent_name="cain", legacy_mode=True)
+            if hasattr(brain, '_conversation_process'):
+                brain_status = "ready"
+                brain_ready = True
+            else:
+                brain_status = "error"
+                error_details = "_conversation_process method not found"
+    except ImportError as e:
+        brain_status = "import_error"
+        error_details = str(e)
+    except Exception as e:
+        brain_status = "error"
+        error_details = str(e)
+
+    return {
+        "status": "ok" if brain_ready else "degraded",
+        "agent": "Cain",
+        "a2a": {
+            "protocol": "jsonrpc",
+            "endpoint": "/a2a/jsonrpc",
+            "brain_status": brain_status,
+            "brain_ready": brain_ready
+        },
+        "uptime_seconds": time.time() - START_TIME,
+        "error": error_details
     }
 
 print(">>> CAIN: FastAPI app created successfully", flush=True)

openclaw/.openclaw/agents/cain_status.json

@@ -1,5 +1,5 @@
 {
   "current_state": "idle",
-  "last_updated": "2026-03-16T06:43:53.088923+00:00",
+  "last_updated": "2026-03-16T07:13:14.677377+00:00",
   "agent": "cain"
 }