Fix ws error receive and send

engine/core/transports.py

@@ -5,6 +5,7 @@ import json
 from abc import ABC, abstractmethod
 from typing import Optional
 from fastapi import WebSocket
+from starlette.websockets import WebSocketState
 from loguru import logger
 
 # Try to import aiortc (optional for WebRTC functionality)
@@ -107,9 +108,24 @@ class SocketTransport(BaseTransport):
 
     async def close(self) -> None:
         """Close the WebSocket connection."""
+        if self._closed:
+            return
+
         self._closed = True
+        if (
+            self.ws.client_state == WebSocketState.DISCONNECTED
+            or self.ws.application_state == WebSocketState.DISCONNECTED
+        ):
+            return
+
         try:
             await self.ws.close()
+        except RuntimeError as e:
+            # Already closed by another task/path; safe to ignore.
+            if "close message has been sent" in str(e):
+                logger.debug(f"WebSocket already closed: {e}")
+                return
+            logger.error(f"Error closing WebSocket: {e}")
         except Exception as e:
             logger.error(f"Error closing WebSocket: {e}")