Match w3c propagation with MCP csharp-sdk and openinference

[codefromthecrypt]

modelcontextprotocol/modelcontextprotocol#414 describes use of request.params._meta which is used here for w3c trace context. However, the w3c fields are under a sub-field request.params._meta.__traceContext here. This means it will have a propagation break with libraries that use request.params._meta plainly, including the official csharp-sdk and openinference MCP instrumentations.

I understand there may be concern about field overlaps, but this concern is normal in otel carriers and well understood. If we can switch to request.params._meta then this project can be compatible with other libraries and re-use any documentation emerging in otel.

Here are a couple known use of request.params._meta, e.g. request.params._meta.traceparent which could join traces here, if it followed the same.

• csharp-sdk here
• Arize OpenInference MCP Python and TypeScript SDKs.