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base repository: modelcontextprotocol/java-sdk
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  • 1 commit
  • 18 files changed
  • 1 contributor

Commits on Oct 31, 2026

  1. Validate SEP-2243 Mcp-Param headers in the modern server 

    - Tools can mark inputSchema arguments with x-mcp-header, so clients
  mirror them into Mcp-Param-{Name} headers. Servers MUST reject a
  request whose headers and body disagree, with 400 / -32020.
- Since only tools/call use those header, they are not part of the
  McpRequestHandler interface, and rather are carried through the
  McpTransportContext.
- The HTTP transport extracts and decodes Mcp-Param-* headers and puts
  them in the context. STDIO puts a marker "not mirrored" value instead.
- Validation happens in ToolsFeature, where we have both the tool
  definition (including x-mcp-header annotations in the schema) and the
  values for the tool call.
- McpHeaderDecoder and McpParamHeaders are public, so other HTTP
  transports can reuse them.
- Mcp-Name now uses the same strict decoder.

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>
    @Kehrlann
    Kehrlann committed Oct 31, 2026
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