Agents Can Mimic Good Design. Ours Know Why It Works

Coding agents for product design have gotten very good at producing UI that looks plausible. Ask one for a settings page, and you get a settings page: cards, toggles, a save button, the works. But when you look closer, the cracks show. The spacing is inconsistent. The empty state is missing. The error copy is a placeholder someone will “fix later.” Two screens that should share the same headline size don’t. What’s happening is that the agent copied the shape of good design, but doesn’t understand the reasons behind it. That’s a real gap with coding agents. Your codebase shows an agent what shipped. It doesn’t show why one component became the standard, why a particular phrase is the one you use, or why a flow is ordered the way it is. Those reasons live in people’s heads, in design reviews, in research readouts, and in a thousand Slack threads. An agent can’t find them, so it guesses. Closing this gap means giving coding agents for product design more than examples to copy. They need the standards, evidence, and reasoning behind every decision. Vercel wrote a great post about this topic. They built a product design skill that gives their…