Been prototyping what a protobuf-connected API would look like: repo here
Important files: backend definition and server definition.
I added two small features on top of the basic connection: idemopotency with OperationContext and timestamps for responses. These are relevant for server environments, but less relevant for local environments.
The code isn’t great yet, but you can definitely see how it would work at the end of the day. Once the server works, the only file to write would be a convenience client to present the exact same API that the STARBackend uses so that you can use both identically, just one over a wire, and one not.
You can add auth middleware if you need server authentication, and the protobuf messages can be intercepted and stored, either for posterity and experimental tracking, or for server-side resource manipulation.