v4.22.1

Name: fastmcp
Author: punkpeye

punkpeye/fastmcpv4.22.1Sep 30, 2026by github-actions[bot]

Upgrading?

What changed from v1.16.22 → v4.22.1?What's new in v31.6.1 after v4.22.1?

AI Summary

Bug fixes for tool/resource error handling, edge protocol initialization, and OpenAPI query parameter handling.

Key Highlights

Fixed unknown tool or resource error code to return -32602
Edge: Initialize with the client's protocol version
OpenAPI: Keep GET requests with referenced array parameters as tools

Full Release Notes

## [4.22.1](https://github.com/punkpeye/fastmcp/compare/v4.22.0...v4.22.1) (2026-09-30)


### Bug Fixes

* answer -32602 for an unknown tool or resource ([#406](https://github.com/punkpeye/fastmcp/issues/406)) ([3cc03cf](https://github.com/punkpeye/fastmcp/commit/3cc03cfea6ca74dd5b0c004de498a3083e8f2348))
* **edge:** answer initialize with the client's protocol version ([#403](https://github.com/punkpeye/fastmcp/issues/403)) ([da0c026](https://github.com/punkpeye/fastmcp/commit/da0c026916fc31976123cdc7e86f88d74c8e14a7))
* **openapi:** keep GETs with referenced array parameters as tools ([#405](https://github.com/punkpeye/fastmcp/issues/405)) ([14e4883](https://github.com/punkpeye/fastmcp/commit/14e4883ce902f773566c72297d7ccf735a1ac6b8))

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