fastmcp.server.middleware.middleware

Functions

mark_interior_dispatched ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L67" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

mark_interior_dispatched() -> None

Record that an interior component middleware chain ran for this message.

make_middleware_wrapper ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L113" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

make_middleware_wrapper(middleware: Middleware, call_next: CallNext[T, R]) -> CallNext[T, R]

Create a wrapper that applies a single middleware to a context. The closure bakes in the middleware and call_next function, so it can be passed to other functions that expect a call_next function.

make_handler_wrapper ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L126" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

make_handler_wrapper(handler: Callable[..., Awaitable[Any]], call_next: CallNext[Any, Any]) -> CallNext[Any, Any]

Classes

CallNext ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L89" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

MiddlewareContext ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L94" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Unified context for all middleware operations.

Methods:

copy ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L109" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

copy(self, **kwargs: Any) -> MiddlewareContext[T]

Middleware ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L136" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Base class for FastMCP middleware with dispatching hooks.

Methods:

on_message ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L204" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_message(self, context: MiddlewareContext[Any], call_next: CallNext[Any, Any]) -> Any

on_request ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L211" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_request(self, context: MiddlewareContext[mt.Request[Any, Any]], call_next: CallNext[mt.Request[Any, Any], Any]) -> Any

on_notification ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L218" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_notification(self, context: MiddlewareContext[mt.Notification[Any, Any]], call_next: CallNext[mt.Notification[Any, Any], Any]) -> Any

on_initialize ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L225" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_initialize(self, context: MiddlewareContext[mt.InitializeRequest], call_next: CallNext[mt.InitializeRequest, mt.InitializeResult | None]) -> mt.InitializeResult | None

on_discover ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L232" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_discover(self, context: MiddlewareContext[mt.DiscoverRequest], call_next: CallNext[mt.DiscoverRequest, mt.DiscoverResult | dict[str, Any]]) -> mt.DiscoverResult | dict[str, Any]

on_call_tool ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L239" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_call_tool(self, context: MiddlewareContext[mt.CallToolRequestParams], call_next: CallNext[mt.CallToolRequestParams, ToolResult]) -> ToolResult

on_read_resource ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L246" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_read_resource(self, context: MiddlewareContext[mt.ReadResourceRequestParams], call_next: CallNext[mt.ReadResourceRequestParams, ResourceResult]) -> ResourceResult

on_get_prompt ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L253" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_get_prompt(self, context: MiddlewareContext[mt.GetPromptRequestParams], call_next: CallNext[mt.GetPromptRequestParams, PromptResult]) -> PromptResult

on_list_tools ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L260" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_list_tools(self, context: MiddlewareContext[mt.ListToolsRequest], call_next: CallNext[mt.ListToolsRequest, Sequence[Tool]]) -> Sequence[Tool]

on_list_resources ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L267" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_list_resources(self, context: MiddlewareContext[mt.ListResourcesRequest], call_next: CallNext[mt.ListResourcesRequest, Sequence[Resource]]) -> Sequence[Resource]

on_list_resource_templates ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L274" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_list_resource_templates(self, context: MiddlewareContext[mt.ListResourceTemplatesRequest], call_next: CallNext[mt.ListResourceTemplatesRequest, Sequence[ResourceTemplate]]) -> Sequence[ResourceTemplate]

on_list_prompts ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/server/middleware/middleware.py#L283" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

on_list_prompts(self, context: MiddlewareContext[mt.ListPromptsRequest], call_next: CallNext[mt.ListPromptsRequest, Sequence[Prompt]]) -> Sequence[Prompt]