middleware

fastmcp.server.middleware.middleware

Functions

make_middleware_wrapper

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.

Classes

CallNext

MiddlewareContext

Unified context for all middleware operations.

Methods:

copy

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

Middleware

Base class for FastMCP middleware with dispatching hooks.

Methods:

on_message

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

on_request

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

on_notification

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

on_call_tool

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

on_read_resource

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

on_get_prompt

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

on_list_tools

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

on_list_resources

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

on_list_resource_templates

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

on_list_prompts

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