Someone explained the entire thing in just one sentence: https://news.ycombinator.com/item?id=49992276 (more links to other explanations here: https://news.ycombinator.com/item?id=49998923)

Cloudflare Blog actually makes a good job explaining it at the very top, also in one sentence: "Convert the MCP tools into a TypeScript API, and then ask an LLM to write code that calls that API.". The rest of the blog post could probably be skipped :)