fastmcp.resources.function_resource

Standalone @resource decorator for FastMCP.

Functions

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

resource(uri: str) -> Callable[[F], F]

Standalone decorator to mark a function as an MCP resource.

Returns the original function with metadata attached. Register with a server using mcp.add_resource().

Classes

DecoratedResource ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/resources/function_resource.py#L41" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Protocol for functions decorated with @resource.

ResourceMeta ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/resources/function_resource.py#L50" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Metadata attached to functions by the @resource decorator.

FunctionResource ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/resources/function_resource.py#L69" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

A resource that defers data loading by wrapping a function.

The function is only called when the resource is read, allowing for lazy loading of potentially expensive data. This is particularly useful when listing resources, as the function won't be called until the resource is actually accessed.

The function can return:

• str for text content (default)
• bytes for binary content
• other types will be converted to JSON

Methods:

from_function ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/resources/function_resource.py#L85" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

from_function(cls, fn: Callable[..., Any], uri: str | AnyUrl | None = None) -> FunctionResource

Create a FunctionResource from a function.

Args:

• fn: The function to wrap
• uri: The URI for the resource (required if metadata not provided)
• metadata: ResourceMeta object with all configuration. If provided, individual parameters must not be passed.
• name, title, etc.: Individual parameters for backwards compatibility. Cannot be used together with metadata parameter.

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

read(self) -> str | bytes | ResourceResult

Read the resource by calling the wrapped function.

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

register_with_docket(self, docket: Docket) -> None

Register this resource with docket for background execution.