Update is_running property logic so that it never evaluates to True if _running_count drops below 0

Author: federicociner

pydantic_ai_slim/pydantic_ai/mcp.py

@@ -309,7 +309,7 @@ async def __aexit__(self, *args: Any) -> bool | None:
     @property
     def is_running(self) -> bool:
         """Check if the MCP server is running."""
-        return bool(self._running_count)
+        return self._running_count > 0
 
     async def _sampling_callback(
         self, context: RequestContext[ClientSession, Any], params: mcp_types.CreateMessageRequestParams