fastmcp.prompts.function_prompt

Standalone @prompt decorator for FastMCP.

Functions

prompt ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/prompts/function_prompt.py#L395" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

prompt(name_or_fn: str | Callable[..., Any] | None = None) -> Any

Standalone decorator to mark a function as an MCP prompt.

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

Classes

DecoratedPrompt ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/prompts/function_prompt.py#L43" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Protocol for functions decorated with @prompt.

PromptMeta ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/prompts/function_prompt.py#L52" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Metadata attached to functions by the @prompt decorator.

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

A prompt that is a function.

Methods:

from_function ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/prompts/function_prompt.py#L73" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

from_function(cls, fn: Callable[..., Any]) -> FunctionPrompt

Create a Prompt from a function.

Args:

• fn: The function to wrap
• metadata: PromptMeta 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.

The function can return:

• str: wrapped as single user Message
• list[Message | str]: converted to list[Message]
• PromptResult: used directly

render ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/fastmcp_slim/fastmcp/prompts/function_prompt.py#L313" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

render(self, arguments: dict[str, Any] | None = None) -> PromptResult

Render the prompt with arguments.