Stop trusting ‘looks about right’: I gave my AI agent a way to verify its UI against Figma (opens in new tab)

I do a lot of UI work, and like a lot of people lately I've been letting an AI agent take the first pass. Point it at a Figma file, let it write the components, come back to something that's 90% there. On a good day that's a huge time save. The problem is the other 10%, and where it hides. It's never an obvious break. It's the padding that's 12px instead of 16. A font weight that's 500 where the design says 600. A border radius that's a couple pixels off. A gradient that starts at the wrong s...