@biomejs/biome@2.5.15 v4.22.2

low risk

leejet/stable-diffusion.cppSep 30, 2026 → Oct 4, 20263 days between releases

What's New

The newer release adds error handling for unsupported MCP headers and modifies tool error reporting.

Breaking Changes

  • Server now returns 400 for an unsupported MCP-Protocol-Version header
  • Throwing tool errors are now returned as isError results instead of being thrown

Bug Fixes

  • Return a throwing tool's error as an isError result
  • Answer 400 for an unsupported MCP-Protocol-Version header
  • Avoid secondary parameter name collisions in OpenAPI
  • Preserve empty property names in JSON Schema issue paths

Upgrade Notes

The provided release notes describe different tools (Biome and FastMCP); there is no upgrade path between them.

The Two Releases

@biomejs/biome@2.5.15

Biome CLI v2.5.15

Sep 30, 2026· 22 days ago

Adds multiple new linter rules for React, Svelte, Astro, and CSS, significantly improves performance of HTML formatting and indexing, and fixes various bugs in configuration and formatting.

Full release notes
v4.22.2

v4.22.2

Oct 4, 2026· 18 days ago

The server now returns a 400 error for an unsupported MCP-Protocol-Version header and returns throwing tool errors as isError results.

Full release notes