In-System DesignWhy builders hand you a lookalike, what has to exist before an agent can use your components, and the MCP setup I use.Prototyping in code is what designers do now, at least according to LinkedIn. I tried it, and after two days I wanted to throw my laptop into the sea. Good news: I came out with a process I actually like, and that works, and that is what this article is. So here is what happened:It started with every team I worked with suddenly turning up with the same frustration. They had connected their design system to an AI builder, described a screen, and got back something that looked finished. Leadership loved it. Then a developer opened the code, said something unrepeatable, and rebuilt it from scratch with the actual design system.I did not understand it either at first. It was connected to the real design system, so what was wrong? So I started poking around...