[hamandcheese]

Debug/tracing data is a great use case for context, for example. If propagating trace information has to be done manually, then you significantly weaken the utility of cross-service tracing. You'll always be questioning if lack of a trace means it didn't happen, or if it means someone forgot to pass along the trace context.

This applies especially to grpc, where everything is optional.

To be clear, I prefer explicit over implicit. But that doesn't always scale well to large orgs.

[jayd16]

I think what's throwing me off is that the examples aren't just transparent things like debug/tracing. They mention credentials and user ids, which the app code can observe and rely on.

The combination of out-of-band/out-of-schema data with APIs to set and get from app code seems like a bad match.

I'd prefer if it was completely invisible to app code and existed only in interceptors.