Lots of people get this confused but MCP has other transports, not only StreamableHTTP but also IO, In Memory, WebSockets.

If it was based on OpenAPI, servers created using transports that are not HTTP would need to implement a http server.

Not much, really. A lot of LLM models need system prompts or fine-tuning to reliably use MCP; (though to be clear you don't NEED to do either of those things, it just dramatically increases the reliability of the LLM)

It's amusing to watch people refer to MCP as a set of tools, or a framework, or an SDK you can invoke, or something or other across a wide range of forums.It's just a standard. A convention. Calling it a protocol is a stretch as well. But there's no meat to it, really.

If you just used Rest API's, you'd need to create little "tools" (say, another executable) locally that the LLM can invoke that can call those API's. MCP standardizes what those tools should act like and their overall lifecycle model.

The references to it being like USB are also quite frankly absurd and delusional.

But that's the caliber of developer we're dealing with today.