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xoai/sage

Universal web development principles — accessibility (WCAG 2.2), performance (Core Web Vitals), security headers (OWASP), SEO, responsive design, error UX, and loading states. Framework-agnostic.

What is sage?

sage is a Claude Code agent skill that universal web development principles — accessibility (WCAG 2.2), performance (Core Web Vitals), security headers (OWASP), SEO, responsive design, error UX, and loading states. Framework-agnostic.

Works with~Claude Code~Codex CLI~Cursor
npx skills add https://github.com/xoai/sage/tree/HEAD/skills/web

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Documentation

web

Layer 1 — Domain Foundation (v2.0)

Universal web development principles that apply to every web project regardless of framework. React, Vue, Svelte, vanilla JS — these principles hold.

Philosophy

This pack encodes the foundational web platform knowledge that agents frequently get right in isolation but miss in practice. An agent knows what ARIA labels are. It still produces a form with no error announcements for screen readers. An agent knows about Core Web Vitals. It still renders a 2MB hero image without dimensions.

The gap isn't knowledge — it's consistent application.

What's Included

TypeCountCoverage
Patterns7Accessibility (WCAG 2.2), performance (Core Web Vitals), security headers (OWASP), SEO, responsive design, error UX, loading states
Anti-patterns6Div soup, missing alt text, layout shift, unprotected forms, client-only critical paths, no security headers
Constitution7principles

Grounded in: W3C WCAG 2.2 (October 2023), Google Core Web Vitals (2025), OWASP Secure Headers Project, OWASP CSP Cheat Sheet, MDN Web Docs, Web Almanac 2025, European Accessibility Act (June 2025).

What This Pack Does NOT Cover

  • Framework-specific patterns (see react, nextjs, etc.)
  • CSS methodology opinions (BEM vs utility-first vs CSS-in-JS)
  • Build tool configuration (Webpack, Vite, Turbopack)
  • Backend/API patterns (see api or baas)

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