Teaching agents product design at Vercel

Coding agents can quickly produce user interfaces by replicating existing patterns and styles, but they struggle to understand the reasoning behind those patterns, which is often found in design reviews and discussions that are not part of the codebase. Vercel addresses this by implementing a system called product-design, which encapsulates product decisions as code, making them available to coding agents. This system comprises an agent skill providing context for product decisions, linters enforcing clear rules, and a review loop that compiles evidence from various sources to update guidelines. The product-design skill is integrated into the repository, organizing decisions, references, and examples to guide agents. The process emphasizes clear decision-making, separating facts from assumptions, and ensuring that changes align with user tasks and product standards. Linters offer fast feedback by enforcing rules, while human oversight is maintained through regular evidence reviews and updates, ensuring that the guidance remains current and effective. This structured approach allows teams to build a similar system tailored to their own standards, enabling agents to make informed decisions while freeing human reviewers to focus on complex judgment calls.