Performance baseline is documented

Without a performance baseline before launch, any future deployment that regresses Core Web Vitals (LCP, CLS, INP) goes undetected until users notice the slowness. ISO 25010:2011 performance-efficiency.time-behaviour defines response time as a measurable quality attribute — not measuring it means you cannot detect regressions. Beyond technical debt, Lighthouse performance scores directly influence Google Search ranking via Core Web Vitals signals: an unmeasured, slow launch can suppress organic traffic from day one without any visible indicator to the developer.

Record a Lighthouse baseline against your production URL immediately after launch and store the report in the repository.

# Record baseline — save output to repo
npx lighthouse https://yoursite.com --output=json --output-path=./lighthouse-baseline.json

For automated enforcement, install @lhci/cli and create .lighthouserc.json with performance score thresholds — Lighthouse CI runs on every PR and fails the build if scores drop below your baseline. At minimum, add your performance targets to the README: Target: LCP < 2.5s, CLS < 0.1, Performance score ≥ 80. Add the web-vitals package to track real-user Core Web Vitals from production traffic.