This is Next.js's internal standard for writing API reference documentation, now packaged as a skill. It walks you through the five categories they use (function, component, file convention, directive, config option) and gives you templates for each. The approach is opinionated: one API per page, scannable structure with tables, example-driven rather than prose-heavy. If you're documenting a large framework or library and want consistency across dozens of reference pages, this gives you a proven pattern. It's built from how Vercel actually documents Next.js, so you're getting their house style rather than generic API doc advice.
npx skills add https://github.com/vercel/next.js --skill write-api-reference