This is probably a semantics problem. You’re right. The models don’t know how to mcp. The harness they run in does though (Claude code, Claude desktop, etc), and dynamically exposes mcp tools as tool calls.
HN loves inventing semantics problems around AI. It's gotten really, really annoying and I'm not sure the people doing it are even close to understanding it.
It doesn't even do that. It's not magic.