> Audits and improves SEO for static HTML sites. Use when the user asks to audit, set up, or improve SEO on a static site (Hugo, Jekyll, 11ty, Gatsby, Next.js static export, hand-rolled HTML, or `wp-static-clone` output), or mentions head metadata, structured data, JSON-LD, sitemaps, IndexNow, Open Graph images, schema endpoints, NLWeb, hreflang, or search engine indexing for a static site. For Astro projects, use `astro-seo` instead — its recipes produce less hand-rolled boilerplate by routing through `@jdevalk/astro-seo-graph`.
npx skills add https://github.com/jdevalk/skills --skill static-seo
Audits and improves the SEO setup of a static HTML site against nine categories — head metadata, structured data, content quality, Open Graph images, sitemaps and indexing, agent discovery, performance, redirects, and CI validation. Recipes are platform-neutral: raw <meta> tags, raw JSON-LD, hand-rolled sitemap.xml, generic CI tooling. Audit framework parallels astro-seo but without the @jdevalk/astro-seo-graph spine.
Code recipes live in AGENTS.md — read it when you need to implement a specific fix. This file has the workflow and audit checklist.
AGENTS.md.metadata-check on every short string the skill generated (titles, descriptions, schema description fields, FAQ answers).Confirm the basics before auditing:
index.html at the repo root, or under _site/ (Jekyll), public/ (Hugo / 11ty / Gatsby), dist/ (Vite / Astro static), out/ (Next.js with output: export). If everything is server-rendered (Express, PHP, dynamic routes), this is the wrong skill — point at astro-seo for Astro, wp-readme-optimizer for WP plugin pages, or recommend a generic SEO audit instead._config.yml / _layouts/ → Jekyllconfig.toml / config.yaml / themes/ → Hugo.eleventy.js / _includes/ → 11tygatsby-config.js / src/components/SEO.* → Gatsbynext.config.js with output: 'export' and pages/_document.tsx → Next.js static exportastro.config.mjs → Astro (in which case use astro-seo instead)wp-static-clone output). Edit the HTML directly or use a post-process script._config.yml, config.toml, astro.config, or hardcoded into a layout. If it's missing, empty, or localhost, flag as a blocking issue before anything else. Canonicals, sitemaps, OG image URLs, and JSON-LD @id values all derive from this.vercel.json, netlify.toml, wrangler.toml, or public/_headers to determine the host. Drives redirect and header syntax in Phase 2./en/, /nl/, /de/) or build-tool i18n config. If yes, hreflang matters; if no, skip it.<head>? Open one built HTML file and inventory: title, description, canonical, robots, Open Graph, Twitter cards, JSON-LD, hreflang. The audit in Phase 1 is faster if you can reference what's there.Ask only what you can't detect.
Score each category out of 10. For each, give 2–4 specific findings that quote the actual HTML, config, or template. Within each category, checks are tiered:
Skip Nice checks for small personal sites unless the user asks for the full treatment.
<title> and <meta name="description">.<link rel="canonical"> set, with tracking parameters stripped, derived from the production origin.noindex (per Google's recommendation).<title> length 30–65 characters, <meta name="description"> length 70–200 characters (the SERP-truncation bounds; same as metadata-check defaults).<meta name="robots"> includes max-snippet:-1, max-image-preview:large, max-video-preview:-1.og:title, og:description, og:image, og:url, og:type, og:site_name) on every page.twitter:card) suppressed when they duplicate Open Graph (Twitter falls back automatically).hreflang alternates on multilingual sites. Skip if monolingual.<meta name="robots"> and single og:image per page (legacy tooling sometimes emits duplicates).<script type="application/ld+json"> block on every important page.@graph rather than a flat Article object — entities wired with @id references so a BlogPosting can point at its Person author and WebPage parent.WebSite, Blog / WebPage, Person / Organization, BlogPosting / Article, BreadcrumbList, ImageObject all present where relevant.publishingPrinciples, copyrightHolder, copyrightYear, knowsAbout, SearchAction.<title> and <meta name="description"> (no duplicate metadata across the site).<h1> per page.<title> and <meta name="description"> audited via metadata-check (Phase 2.5) for front-loading, concreteness, and SERP fit.readability-check for individual long-form posts (don't bulk-audit).<img> has an alt attribute (or alt="" / role="presentation" for decorative)./foo/) not absolute (https://...) — survives domain changes and previews./og/<slug>.jpg) so adding a page automatically gets an image.<img> in body content has an alt attribute (or alt="" / role="presentation"). Validated in CI via html-proofer or similar./sitemap.xml (or /sitemap_index.xml for split sitemaps) reachable, valid XML, every URL returns 200.robots.txt present at the site root and references the sitemap.<link rel="alternate" type="application/rss+xml">, contains full post content (not truncated excerpts).sitemap-posts.xml, sitemap-pages.xml) — easier to debug indexing in GSC.<lastmod> populated from git commit timestamps (most accurate), build timestamps (acceptable), or frontmatter dates (last resort). Filesystem mtime from CI checkout is wrong — it's the checkout date, not the content date./<key>.txt route at the site root, plus a build-or-deploy hook that POSTs new URLs to https://api.indexnow.org/IndexNow. Gate the submission on the production host (e.g. CF_PAGES_BRANCH=main, VERCEL_ENV=production, CONTEXT=production) — unconditional submission pings the endpoint from local builds with URLs the production host hasn't served yet, which gets the key marked invalid (403) and forces rotation./schema/<type>.json) exposing corpus-wide JSON-LD per content type. Static JSON files committed to the repo or regenerated by the build./schemamap.xml) listing every schema endpoint, with Schemamap: directive in robots.txt.llms.txt at the site root listing pages (title + description) for LLM consumers. Static text file; one line per page./blog/post.md next to /blog/post/) serving clean markdown with YAML frontmatter so AI agents can consume content without HTML parsing. Either commit .md siblings, or use a Cloudflare Transform Rule + Vary: Accept for content negotiation (CF Pages strips custom Vary headers, so use the Transform Rule's URL rewrite alone — recipe in AGENTS.md)./.well-known/api-catalog per RFC 9727, as application/linkset+json (RFC 9264). Lists schema endpoints, schemamap, RSS feed, and any site-specific APIs. Static JSON file.robots.txt (Content-Signal: ai-train=yes, search=yes, ai-input=yes or your preferred policy). One line, IETF draft, low cost.Link header on /* pointing to discovery files (sitemap, llms.txt, api-catalog, schemamap). Agents reading response headers find them without parsing HTML. Host-specific (_headers on Cloudflare Pages / Netlify, vercel.json on Vercel, server config elsewhere)./.well-known/mcp/server-card.json and / or A2A agent card at /.well-known/agent-card.json. Only relevant when the site exposes an MCP server or A2A agent.<link rel="nlweb"> pointing to a conversational endpoint. NLWeb adoption is early; the tag is one line and worth having, but not a scoring blocker in 2026./.well-known/ai-catalog.json, listing what the domain offers (MCP server, A2A agent, OKF bundle, site-specific APIs). v0.9 draft, so optional — but it's the discovery layer the MCP / A2A cards and OKF bundle pay off through. Two gotchas: the base spec (Agent-Card/ai-catalog) names the media-type field mediaType while the ARD layer (ards-project/ard-spec) names it type — emit both keys with the same value so the entry validates under either reading (both specs require consumers to ignore unknown keys). ARD also adds an optional representativeQueries array of sample prompts per entry. Static JSON file..tar.gz, with index files in between. Serving and discovery are explicit non-goals of OKF — that's what the ARD catalog entry is for. v0.9 draft, optional. There's no registered media type yet, so the interim string is application/okf-bundle+gzip (tracked in knowledge-catalog#111 and ard-spec#27); mark it interim, it may change. Best generated from the same source the rest of the site derives from rather than a hand-maintained copy.Cache-Control: public, max-age=31536000, immutable (or equivalent) so they only download once.woff2 via <link rel="preload" as="font" crossorigin>.No-Vary-Search response header strips UTM parameters from cache key (so /?utm_source=x and / share a cache entry).loading="lazy" below the fold._redirects / vercel.json / server config maintained for every URL that ever existed and moved.301 not 302 for permanent moves.404.html (or equivalent) returns a 404 status, not 200. Verify with curl -I against a deliberately wrong URL.<title> and <meta name="description">, flags anything outside SERP-truncation bounds (title 30–65, description 70–200).Based on the audit, produce concrete code. Always ask before overwriting. Read AGENTS.md for detailed recipes.
Branch on the Phase 0 findings. If the site is a known build tool (Hugo, Jekyll, 11ty, Gatsby, Next.js), apply changes at the source level (templates, config, frontmatter). For hand-rolled or scraped HTML, post-process the built output. The recipes in AGENTS.md are output-shape recipes — show the HTML you want to land at — and a per-tool note on where to plumb them through.
AGENTS.md sections: Head metadata (the canonical block), JSON-LD graph, OG image generation (build-script options), sitemap.xml and robots.txt, IndexNow, llms.txt, Markdown alternates, API catalog, Content Signals, Link headers, Performance headers, Redirects by host, CI workflows.
Invoke the metadata-check skill on every short string the skill generated or modified: page titles, meta descriptions, schema description fields, FAQ answers, and any frontmatter excerpt values you wrote. It checks front-loading, concreteness, filler, active voice, title / description duplication, difficult words, SERP-truncation fit (title 30–65, description 70–200), and one-idea-per-field. Apply fixes directly. Skip the pass for technical strings (URLs, schema @id values, enum values).
If the project has a blog or docs section, mention as a follow-up that the readability-check skill can audit individual posts for multi-paragraph prose quality — but don't audit the entire content corpus yourself.
<head> should be clean, canonical correct, JSON-LD graph present and linked./sitemap.xml exists, returns 200, and references the right URLs./robots.txt references the sitemap and includes Content Signals./<key>.txt.linkinator http://localhost:8080 --recurse)..txt verification file.## Static SEO audit: [site name]
### Score
| Category | Score |
| ------------------------------------- | ----: |
| 1. Head metadata | x/10 |
| 2. Structured data / JSON-LD | x/10 |
| 3. Content quality | x/10 |
| 4. Open Graph images | x/10 |
| 5. Sitemaps and indexing | x/10 |
| 6. Agent discovery | x/10 |
| 7. Performance | x/10 |
| 8. Redirects and error handling | x/10 |
| 9. CI validation | x/10 |
| **Total** | xx/90 |
### Findings
[Grouped by category. Quote actual HTML / config. Be specific.]
### Files generated or changed
[List with short description of each.]
### Next steps
[Non-file tasks: GSC, Bing Webmaster Tools, IndexNow key, analytics.]
_redirects vs vercel.json), give both forms.astro-seo for Astro. That skill produces less hand-rolled boilerplate via @jdevalk/astro-seo-graph. static-seo is for everything else.Take jdevalk/static-seo from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.