> ## Documentation Index > Fetch the complete documentation index at: https://gofastmcp.com/llms.txt > Use this file to discover all available pages before exploring further. # components # `fastmcp.utilities.components` ## Functions ### `get_fastmcp_metadata` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} get_fastmcp_metadata(meta: dict[str, Any] | None) -> FastMCPMeta ``` Extract FastMCP metadata from a component's meta dict. Handles both the current `fastmcp` namespace and the legacy `_fastmcp` namespace for compatibility with older FastMCP servers. ## Classes ### `FastMCPMeta` ### `FastMCPComponent` Base class for FastMCP tools, prompts, resources, and resource templates. **Methods:** #### `make_key` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} make_key(cls, identifier: str) -> str ``` Construct the lookup key for this component type. **Args:** * `identifier`: The raw identifier (name for tools/prompts, uri for resources) **Returns:** * A prefixed key like "tool:name" or "resource:uri" #### `key` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} key(self) -> str ``` The globally unique lookup key for this component. Format: "{key_prefix}:{identifier}@{version}" or "{key_prefix}:{identifier}@" e.g. "tool:my\_tool\@v2", "tool:my\_tool@", "resource:file://x.txt@" The @ suffix is ALWAYS present to enable unambiguous parsing of keys (URIs may contain @ characters, so we always include the delimiter). Subclasses should override this to use their specific identifier. Base implementation uses name. Prefer `.key` over ad-hoc `name or uri or uri_template` logic for any cross-component identity work (dedupe, grouping, collision detection, lookup tables). It encodes type, identifier, and version, so variants of the same component don't falsely collide with each other, and cross-type identifiers (e.g. a tool and a resource both named "foo") can't clash. #### `get_meta` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} get_meta(self) -> dict[str, Any] ``` Get the meta information about the component. Returns a dict that always includes a `fastmcp` key containing: * `tags`: sorted list of component tags * `version`: component version (only if set) Internal keys (prefixed with `_`) are stripped from the fastmcp namespace. #### `enable` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} enable(self) -> None ``` Removed in 3.0. Use server.enable(keys=\[...]) instead. #### `disable` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} disable(self) -> None ``` Removed in 3.0. Use server.disable(keys=\[...]) instead. #### `copy` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} copy(self) -> Self ``` Create a copy of the component. #### `register_with_docket` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} register_with_docket(self, docket: Docket) -> None ``` Register this component with docket for background execution. No-ops if task\_config.mode is "forbidden". Subclasses override to register their callable (self.run, self.read, self.render, or self.fn). #### `add_to_docket` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} add_to_docket(self, docket: Docket, *args: Any, **kwargs: Any) -> Execution ``` Schedule this component for background execution via docket. Subclasses override this to handle their specific calling conventions: * Tool: add\_to\_docket(docket, arguments: dict, \*\*kwargs) * Resource: add\_to\_docket(docket, \*\*kwargs) * ResourceTemplate: add\_to\_docket(docket, params: dict, \*\*kwargs) * Prompt: add\_to\_docket(docket, arguments: dict | None, \*\*kwargs) The \*\*kwargs are passed through to docket.add() (e.g., key=task\_key). #### `get_span_attributes` ```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}} get_span_attributes(self) -> dict[str, Any] ``` Return span attributes for telemetry. Subclasses should call super() and merge their specific attributes.