fastmcp.utilities.lifespan

Lifespan utilities for combining async context manager lifespans.

Functions

combine_lifespans ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/utilities/lifespan.py#L12" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

combine_lifespans(*lifespans: Callable[[AppT], AbstractAsyncContextManager[Mapping[str, Any] | None]]) -> Callable[[AppT], AbstractAsyncContextManager[dict[str, Any]]]

Combine multiple lifespans into a single lifespan.

Useful when mounting FastMCP into FastAPI and you need to run both your app's lifespan and the MCP server's lifespan.

Works with both FastAPI-style lifespans (yield None) and FastMCP-style lifespans (yield dict). Results are merged; later lifespans override earlier ones on key conflicts.

Lifespans are entered in order and exited in reverse order (LIFO).

Args:

• *lifespans: Lifespan context manager factories to combine.

Returns:

• A combined lifespan context manager factory.