Claude Code: Add A2A diagnostics and fix stage reporting

- Update status file to RUNNING_A2A_READY when app starts
- Add logging to /a2a/jsonrpc endpoint for debugging
- Add /a2a/self-test endpoint for A2A diagnostics
- Fix stage mismatch between status file and health checks

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

app.py

@@ -154,8 +154,10 @@ async def a2a_jsonrpc(request: Request):
 
     Handles message/send requests from other agents in the HuggingClaw World family.
     """
+    print(f">>> CAIN A2A: Received request at {time.time()}", flush=True)
     try:
         payload = await request.json()
+        print(f">>> CAIN A2A: Payload method={payload.get('method')}, id={payload.get('id')}", flush=True)
 
         # Validate JSON-RPC 2.0 basic structure
         if payload.get("jsonrpc") != "2.0":
@@ -274,6 +276,59 @@ async def api_status():
     }
 
 
+# ============================================================================
+# A2A SELF-TEST ENDPOINT - Test A2A endpoint without external agent
+# ============================================================================
+@app.get("/a2a/self-test")
+async def a2a_self_test():
+    """
+    Self-test endpoint for A2A functionality.
+    Tests brain import and returns detailed status.
+    """
+    print(f">>> CAIN A2A: Self-test requested", flush=True)
+    test_results = {
+        "timestamp": time.time(),
+        "tests": {}
+    }
+
+    # Test 1: Can we import openclaw?
+    try:
+        import openclaw
+        test_results["tests"]["openclaw_import"] = {"status": "pass", "path": str(openclaw.__file__)}
+    except Exception as e:
+        test_results["tests"]["openclaw_import"] = {"status": "fail", "error": str(e)}
+
+    # Test 2: Can we import brain_minimal?
+    try:
+        from agents import brain_minimal
+        test_results["tests"]["brain_minimal_import"] = {"status": "pass"}
+    except Exception as e:
+        test_results["tests"]["brain_minimal_import"] = {"status": "fail", "error": str(e)}
+
+    # Test 3: Can we get a brain instance?
+    try:
+        from agents import brain_minimal
+        brain = brain_minimal.get_brain(agent_name="cain", legacy_mode=True)
+        test_results["tests"]["get_brain"] = {"status": "pass", "agent_name": getattr(brain, 'agent_name', 'unknown')}
+    except Exception as e:
+        test_results["tests"]["get_brain"] = {"status": "fail", "error": str(e)}
+
+    # Test 4: Can we call _conversation_process?
+    try:
+        from agents import brain_minimal
+        brain = brain_minimal.get_brain(agent_name="cain", legacy_mode=True)
+        result = brain._conversation_process("test")
+        test_results["tests"]["conversation_process"] = {"status": "pass", "success": result.get("success")}
+    except Exception as e:
+        test_results["tests"]["conversation_process"] = {"status": "fail", "error": str(e)}
+
+    # Overall status
+    all_pass = all(t.get("status") == "pass" for t in test_results["tests"].values())
+    test_results["overall_status"] = "pass" if all_pass else "partial_fail"
+
+    return test_results
+
+
 # ============================================================================
 # A2A HEALTH CHECK ENDPOINT - For agents to verify Cain's A2A availability
 # ============================================================================
@@ -340,8 +395,34 @@ async def a2a_health():
 print(">>> CAIN: FastAPI app created successfully", flush=True)
 print(">>> CAIN: A2A endpoint registered at /a2a/jsonrpc", flush=True)
 print(">>> CAIN: A2A health check at /a2a/health", flush=True)
+print(">>> CAIN: A2A self-test at /a2a/self-test", flush=True)
 print(">>> CAIN: A2A diagnostics at /a2a/diagnostics", flush=True)
 
+# Update status file to indicate app is ready (A2A available)
+try:
+    import json
+    from datetime import datetime
+    status_path = os.environ.get('CAIN_STATUS_PATH', '/data/cain_status.json')
+    status_data = {
+        "current_state": "idle",
+        "stage": "RUNNING_A2A_READY",
+        "last_updated": datetime.utcnow().isoformat() + "+00:00",
+        "agent": "cain",
+        "a2a": {
+            "endpoint": "/a2a/jsonrpc",
+            "enabled": True,
+            "status": "ready"
+        }
+    }
+    # Ensure directory exists
+    from pathlib import Path
+    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)
+except Exception as e:
+    print(f">>> CAIN WARNING: Could not update status file: {e}", flush=True)
+
 # Verify openclaw can be imported at startup
 try:
     import openclaw