--- title: low_level sidebarTitle: low_level --- # `fastmcp.server.low_level` ## Classes ### `MiddlewareServerSession` ServerSession that routes initialization requests through FastMCP middleware. **Methods:** #### `fastmcp` ```python fastmcp(self) -> FastMCP ``` Get the FastMCP instance. ### `LowLevelServer` **Methods:** #### `fastmcp` ```python fastmcp(self) -> FastMCP ``` Get the FastMCP instance. #### `create_initialization_options` ```python create_initialization_options(self, notification_options: NotificationOptions | None = None, experimental_capabilities: dict[str, dict[str, Any]] | None = None, **kwargs: Any) -> InitializationOptions ``` #### `run` ```python run(self, read_stream: MemoryObjectReceiveStream[SessionMessage | Exception], write_stream: MemoryObjectSendStream[SessionMessage], initialization_options: InitializationOptions, raise_exceptions: bool = False, stateless: bool = False) ``` Overrides the run method to use the MiddlewareServerSession.