You need some kind of structured way to describe the action to take, what the result is or what the error is. so the client and server can actually parse the da

You need some kind of structured way to describe the action to take, what the result is or what the error is. so the client and server can actually parse the data. that's the protocol, whether its something formal like rpc libraries, or "REST"-ish or w/e json-rpc is probably what your describing over http, maybe if you squint enough graphql too