MCP is just RPC over a long-lived connection, most cases being a Websocket. IMO RPC is easier to setup because:
1. There's less bikeshedding for the authors about whether modifying a field in a user object should be a PUT or a POST replacing the original user object. I've spent a non-trivial amount of time bikeshedding over REST verbs.
2. LLMs don't need to understand the REST semantics of the API. It can just look at available RPC methods and make the RPC call it thinks will work.
1. There's less bikeshedding for the authors about whether modifying a field in a user object should be a PUT or a POST replacing the original user object. I've spent a non-trivial amount of time bikeshedding over REST verbs.
2. LLMs don't need to understand the REST semantics of the API. It can just look at available RPC methods and make the RPC call it thinks will work.
I think that's really it.