Frontend SEO (portable, builder-based)

Portable skill — readable by Claude Code, OpenCode, Codex, Cursor, Windsurf, and others. This skill describes an SEO system — a set of pure builder functions plus a thin framework adapter — not a component library or a visual style. It pairs with the frontend-architecture skill: the SEO system lives in a single service module (services/seo/) and is consumed through one barrel.

The goal: every route ships correct, consistent, machine-readable metadata without anyone copy-pasting <meta> tags. Site identity lives in one constants module, URLs are always absolute and canonical, and search engines get a sitemap, robots rules, an RSS feed, and typed JSON-LD derived from the same content the app already renders.

0. The five core ideas