Your trace shows api-gateway calling orders, then stops. orders definitely called inventory, but inventory appears as a separate, parentless trace. The context did not propagate. It happens at four specific boundaries, and each needs a different fix. Boundary 1: protocol translation W3C Trace Context travels as a traceparent HTTP header. gRPC has metadata, not headers, and the mapping is not automatic unless an instrumented interceptor does it. from __future__ i...