How our agents build on-brand pages with design.md

Vercel's design.md approach turns recurring design corrections into reusable agent guidance. Its account separates judgment about page structure from a shared stylesheet and automated checks. A cramped evidence table, for example, prompted both a written layout rule and a check that could detect the same failure later.

In a six-page comparison across three desktop scenarios, pages generated with the guidance contained 39 known failures versus 91 without it, a 57% reduction. Those checks measured previously identified mistakes, and every page still had a problem serious enough to block shipping. The supported gain is fewer recurring errors in this small test, with human review still needed for overall design quality.