Related: #6583 (comment)

See test_sse_transport_detection_v2 test in test_mcp.pyas a reference to this behaviour.

Because we don't propagate these correctly, traces lose everything that's set on the isolation and current scopes, we lose the parent-child span relationship, attributes that were set are lost, andwe get two traces instead of one.

Note: Rather than working to propagate the context variables, we may want to consider dropping support for the SSE transport as current data points to most users using the HTTP transport.