# Lessons Learned — mgf-uitest-web

> Append-only, dated lessons log (DOC-19). Newest first. A lesson earns its place by having cost real time or nearly shipped a defect.

## 2026-07-16 — repo birth
- Seeded at initial release. Entries are added as lessons arise.
- Browser must be **pinned** (Playwright bundled Chromium), never a silent system-browser fallback: a different browser resolves CSS/relative URLs differently and invents findings that do not reproduce.
