fix: accept metadata on legacy conformance initialize - #20
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Treat session-era initialize requests as legacy based on params.protocolVersion even when optional request metadata is present. This prevents MCP Python SDK 2.x initialization from being rejected as modern traffic. Signed-off-by: lucarlig <luca.carlig@ibm.com>
lucarlig
marked this pull request as ready for review
September 18, 2026 17:48
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Summary
initializerequests fromparams.protocolVersionbefore the harness's modern-era routingRequestParams._meta, including the empty metadata object emitted by MCP Python SDK 2.xThis is the harness-side fix for the failure seen in IBM/mcp-context-forge#6868. The same root fix is proposed upstream in modelcontextprotocol/conformance#507; keeping it in the pinned fixture patch unblocks ContextForge without waiting for a new upstream conformance release.
Validation
docker/mcp-conformance-server.Dockerfilefrom the pinned alpha.11 revisionlegacymode and received HTTP 200 plusMcp-Session-Idfor aninitializerequest containing_meta: {}cargo test --locked(431 tests)git diff --check