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Two community-contributed fixes: auth headers from MCP transport no longer leak through to downstream OpenAPI APIs, and background task workers now correctly receive the originating request ID. Plus a new docs example for context-aware tool factories.
First patch after 3.0 β mostly smoothing out rough edges discovered in the wild. The big ones: middleware state that wasn't surviving the trip to tool handlers now does, Tool.from_tool() accepts callables again, OpenAPI schemas with circular references no longer crash discovery, and decorator overloads now return the correct types in function mode. Also adds verify_id_token to OIDCProxy for pr...
FastMCP 3.0 is stable. Two betas, two release candidates, 21 new contributors, and more than 100,000 pre-release installs later β the architecture held up, the upgrade path was smooth, and we're shipping it.
The surface API is largely unchanged β @mcp.tool() still works exactly as before. What changed is everything underneath: a provider/transform architecture that makes FastMCP extensible, o...
FastMCP 3 rc3 is being released solely to ensure that the release pipeline is intact from the new repo. If successful, it will be followed immediately by 3.0 GA.
RC2 is a small release with a bugfix and a breaking change (that should have been in RC1): fastmcp dev is now a subcommand group, with the inspector moving to fastmcp dev inspector. We're planning to add new dev tools β mock servers, apps testing β that the Inspector alone can't handle, and this is the right time to claim the CLI namespace.