This is the inverse of an audit. Instead of checking whether your app matches a standard, you point it at a reference app and it builds the standard. It walks every screen, captures screenshots of all states (hover, empty, error, loading), records copy verbatim, documents keyboard shortcuts and responsive breakpoints, then organizes everything into a reusable pattern library. You'd run this before building a feature to study how best-in-class apps handle it, or to create a concrete benchmark for later audits. The guide is thorough about ethics: use your own account, respect rate limits, keep competitor screenshots internal. Pairs naturally with ux-audit once you have the extract.
npx skills add https://github.com/jezweb/claude-skills --skill ux-extract