Claude Code: add /debug/health endpoint with uptime, memory, status, and modules

- Add GET /debug/health endpoint returning JSON status report
- Track application uptime from START_TIME
- Report memory usage (RSS and VMS) via psutil
- Include last 5 lines from cain_status.json
- List loaded Python modules (first 100)

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

app.py

@@ -14,6 +14,9 @@ import sys
 from datetime import datetime
 import asyncio
 from contextlib import asynccontextmanager
+import time
+import json
+import psutil
 
 # Add /app to sys.path for proper package imports
 sys.path.insert(0, "/app")
@@ -23,6 +26,9 @@ from openclaw.core.system_logger import log_startup, log_heartbeat, get_last_lin
 # Import error handlers
 from error_handlers import handle_status_file_read, handle_brain_response, handle_websocket_send
 
+# Track startup time for uptime calculation
+START_TIME = time.time()
+
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
@@ -172,6 +178,47 @@ async def admin_system():
     }
 
 
+@app.get("/debug/health")
+async def debug_health():
+    """Debug health endpoint with detailed system status."""
+    # 1. Uptime in seconds
+    uptime = time.time() - START_TIME
+
+    # 2. Current memory usage of the current process (brain_minimal runs in same process)
+    process = psutil.Process(os.getpid())
+    memory_info = process.memory_info()
+    memory_mb = memory_info.rss / 1024 / 1024  # Convert to MB
+
+    # 3. Last 5 lines from cain_status.json (read as structured JSON)
+    cain_status_path = "/app/openclaw/.openclaw/agents/cain_status.json"
+    cain_status_lines = []
+    try:
+        if os.path.exists(cain_status_path):
+            with open(cain_status_path, "r") as f:
+                content = f.read()
+                lines = content.strip().split("\n")
+                cain_status_lines = lines[-5:] if len(lines) > 5 else lines
+        else:
+            cain_status_lines = ["cain_status.json not found"]
+    except Exception as e:
+        cain_status_lines = [f"Error reading cain_status.json: {str(e)}"]
+
+    # 4. List of loaded Python modules
+    loaded_modules = sorted([name for name in sys.modules.keys() if not name.startswith("_")])[:100]
+
+    return {
+        "uptime_seconds": round(uptime, 2),
+        "memory": {
+            "rss_mb": round(memory_mb, 2),
+            "vms_mb": round(memory_info.vms / 1024 / 1024, 2)
+        },
+        "cain_status_last_lines": cain_status_lines,
+        "loaded_modules_count": len(loaded_modules),
+        "loaded_modules": loaded_modules,
+        "timestamp": datetime.utcnow().isoformat() + "+00:00"
+    }
+
+
 if __name__ == "__main__":
     import uvicorn
     uvicorn.run(app, host="0.0.0.0", port=7860)