Isn't part of the issue that LLM's are relatively bad at REST and json and all that?

I remember like 2 years ago there was big hype/revolution around ChatGPT finally being able to return ONLY valid json when you asked it to. So apparently LLMs are not that good at scripting without mistakes.

Having said that, I honestly have no clue what MCP looks like or is lol :p

MCP is a form of JSON-RPC over HTTP, so I don't think it has anything to do with that.

MCP is just json.

But to your last point: go look it up, have a read through their client/server implementations (for your language of choice). It doesn't actually take that long because the concept is actually rather simple, so I totally recommend it.

Maybe not, I think they trained the model to be especially capable of MCP tool use, and generated data this way. Other formats and systems might be slightly worse, and the whole model would probably not handle such a diversity of tools if all it had was trained on much less diverse API integrations.