Demo Video Skill — visual validation for web apps

Record a captioned walkthrough video of a running web app, verify it frame-by-frame, convert to mp4, and deliver it. Battle-tested on real client-feedback proof videos.

This is the harness's default visual validation for web projects: a demo video walks a real user flow end-to-end and doubles as a passing E2E test, so "it works" is proven visually, not claimed. It complements [[visual-validation]] (autonomous screenshot-regression checks) and [[playwright-testing]] (the E2E suite): screenshots catch pixel regressions, the suite proves behavior, and a demo video proves the whole user-facing flow the way a person would see it.

The method