That’s a pretty good idea. It does expand the complexity of the client a bit, but at least it’s in an opt-in way so it doesn’t strictly need to be done for cros

That’s a pretty good idea. It does expand the complexity of the client a bit, but at least it’s in an opt-in way so it doesn’t strictly need to be done for cross-language clients. But what would the benefit(s) to users be? If they are deserializing a protobuf error, they are almost certainly using a generated client, so I don’t think they will know or care how the error was encoded. (This might be better as a github issue to keep a visible record of the design for others.)