the MCP spec as it stands today is pretty half-baked. It’s pretty clear that the first edition was trying to emulate STDIO over HTTP, but that meant holding open a connection indefinitely. The new revision tries to solve this by letting you hold open as many connections as you want! but that makes it vague about message delivery ordering when you have multiple streams open. There even seems to be part of the spec that is logically impossible - people are wrestling with it in the GitHub issues.

which is to say: I’m not sure it actually wins, technically, over the OpenAI/OpenAPI idea from last year, which was at least easy to understand