--- title: fastmcp_provider sidebarTitle: fastmcp_provider --- # `fastmcp.server.providers.fastmcp_provider` FastMCPProvider for wrapping FastMCP servers as providers. This module provides the `FastMCPProvider` class that wraps a FastMCP server and exposes its components through the Provider interface. It also provides FastMCPProvider* component classes that delegate execution to the wrapped server's middleware, ensuring middleware runs when components are executed. ## Classes ### `FastMCPProviderTool` Tool that delegates execution to a wrapped server's middleware. When `run()` is called, this tool invokes the wrapped server's `_call_tool_middleware()` method, ensuring the server's middleware chain is executed. **Methods:** #### `wrap` ```python wrap(cls, server: Any, tool: Tool) -> FastMCPProviderTool ``` Wrap a Tool to delegate execution to the server's middleware. #### `run` ```python run(self, arguments: dict[str, Any]) -> ToolResult ``` Delegate to child server's call_tool() without task_meta. This is called when the tool is used within a TransformedTool forwarding function or other contexts where task_meta is not available. #### `get_span_attributes` ```python get_span_attributes(self) -> dict[str, Any] ``` ### `FastMCPProviderResource` Resource that delegates reading to a wrapped server's read_resource(). When `read()` is called, this resource invokes the wrapped server's `read_resource()` method, ensuring the server's middleware chain is executed. **Methods:** #### `wrap` ```python wrap(cls, server: Any, resource: Resource) -> FastMCPProviderResource ``` Wrap a Resource to delegate reading to the server's middleware. #### `get_span_attributes` ```python get_span_attributes(self) -> dict[str, Any] ``` ### `FastMCPProviderPrompt` Prompt that delegates rendering to a wrapped server's render_prompt(). When `render()` is called, this prompt invokes the wrapped server's `render_prompt()` method, ensuring the server's middleware chain is executed. **Methods:** #### `wrap` ```python wrap(cls, server: Any, prompt: Prompt) -> FastMCPProviderPrompt ``` Wrap a Prompt to delegate rendering to the server's middleware. #### `render` ```python render(self, arguments: dict[str, Any] | None = None) -> PromptResult ``` Delegate to child server's render_prompt() without task_meta. This is called when the prompt is used within a transformed context or other contexts where task_meta is not available. #### `get_span_attributes` ```python get_span_attributes(self) -> dict[str, Any] ``` ### `FastMCPProviderResourceTemplate` Resource template that creates FastMCPProviderResources. When `create_resource()` is called, this template creates a FastMCPProviderResource that will invoke the wrapped server's middleware when read. **Methods:** #### `wrap` ```python wrap(cls, server: Any, template: ResourceTemplate) -> FastMCPProviderResourceTemplate ``` Wrap a ResourceTemplate to create FastMCPProviderResources. #### `create_resource` ```python create_resource(self, uri: str, params: dict[str, Any]) -> Resource ``` Create a FastMCPProviderResource for the given URI. The `uri` is the external/transformed URI (e.g., with namespace prefix). We use `_original_uri_template` with `params` to construct the internal URI that the nested server understands. #### `read` ```python read(self, arguments: dict[str, Any]) -> str | bytes | ResourceResult ``` Read the resource content for background task execution. Reads the resource via the wrapped server and returns the ResourceResult. This method is called by Docket during background task execution. #### `register_with_docket` ```python register_with_docket(self, docket: Docket) -> None ``` No-op: the child's actual template is registered via get_tasks(). #### `add_to_docket` ```python add_to_docket(self, docket: Docket, params: dict[str, Any], **kwargs: Any) -> Execution ``` Schedule this template for background execution via docket. The child's FunctionResourceTemplate.fn is registered (via get_tasks), and it expects splatted **kwargs, so we splat params here. #### `get_span_attributes` ```python get_span_attributes(self) -> dict[str, Any] ``` ### `FastMCPProvider` Provider that wraps a FastMCP server. This provider enables mounting one FastMCP server onto another, exposing the mounted server's tools, resources, and prompts through the parent server. Components returned by this provider are wrapped in FastMCPProvider* classes that delegate execution to the wrapped server's middleware chain. This ensures middleware runs when components are executed. **Methods:** #### `list_tools` ```python list_tools(self) -> Sequence[Tool] ``` List all tools from the mounted server as FastMCPProviderTools. Calls the nested server's middleware to list tools, then wraps each tool as a FastMCPProviderTool that delegates execution to the nested server's middleware. #### `get_tool` ```python get_tool(self, name: str, version: VersionSpec | None = None) -> Tool | None ``` Get a tool by name as a FastMCPProviderTool. Passes the full VersionSpec to the nested server, which handles both exact version matching and range filtering. #### `list_resources` ```python list_resources(self) -> Sequence[Resource] ``` List all resources from the mounted server as FastMCPProviderResources. Calls the nested server's middleware to list resources, then wraps each resource as a FastMCPProviderResource that delegates reading to the nested server's middleware. #### `get_resource` ```python get_resource(self, uri: str, version: VersionSpec | None = None) -> Resource | None ``` Get a concrete resource by URI as a FastMCPProviderResource. Passes the full VersionSpec to the nested server, which handles both exact version matching and range filtering. #### `list_resource_templates` ```python list_resource_templates(self) -> Sequence[ResourceTemplate] ``` List all resource templates from the mounted server. Returns FastMCPProviderResourceTemplate instances that create FastMCPProviderResources when materialized. #### `get_resource_template` ```python get_resource_template(self, uri: str, version: VersionSpec | None = None) -> ResourceTemplate | None ``` Get a resource template that matches the given URI. Passes the full VersionSpec to the nested server, which handles both exact version matching and range filtering. #### `list_prompts` ```python list_prompts(self) -> Sequence[Prompt] ``` List all prompts from the mounted server as FastMCPProviderPrompts. Returns FastMCPProviderPrompt instances that delegate rendering to the wrapped server's middleware. #### `get_prompt` ```python get_prompt(self, name: str, version: VersionSpec | None = None) -> Prompt | None ``` Get a prompt by name as a FastMCPProviderPrompt. Passes the full VersionSpec to the nested server, which handles both exact version matching and range filtering. #### `get_tasks` ```python get_tasks(self) -> Sequence[FastMCPComponent] ``` Return task-eligible components from the mounted server. Returns the child's ACTUAL components (not wrapped) so their actual functions get registered with Docket. Uses _source_get_tasks() to get components with child server's transforms applied, then applies this provider's transforms for correct registration keys. #### `lifespan` ```python lifespan(self) -> AsyncIterator[None] ``` Start the mounted server's user lifespan. This starts only the wrapped server's user-defined lifespan, NOT its full _lifespan_manager() (which includes Docket). The parent server's Docket handles all background tasks.