forge-performance

What problem does it solve?

It prevents AI-generated frontends from shipping oversized assets and bloated bundles that harm Core Web Vitals, causing slow first loads, janky interactions, and layout shifts that users feel immediately.

Core Features & Use Cases

• Core Web Vitals-first guidance: Targets LCP ≤ 2.5s, INP ≤ 200ms, and CLS ≤ 0.1, with field-data measurement emphasis.
• Practical asset discipline: Enforces modern image formats, responsive srcset + sizes, correct loading/fetchpriority, and explicit width/height (or aspect-ratio) to eliminate CLS.
• Bundle, CSS, and font constraints: Covers code-splitting, tree-shake-friendly imports, critical CSS, and web font loading that avoids FOIT/FOUT via font-display: swap, plus critical font preloading and font subsetting.
• Third-party and preloading rules: Requires deferring/asyncing third-party scripts, and prescribes “preload only the LCP asset” to avoid over-preloading penalties.
• Verification checklist: Provides a manual audit list aligned to real performance regressions (bundle audits, Lighthouse, and CI budgets).

Quick Start

Use the forge-performance skill to audit and rewrite your proposed web UI changes so they meet LCP, INP, and CLS targets while applying modern images, correct font loading, and bundle/CSS discipline.