SEO your agent can actually reproduce.

• Zero dependency

  Markdown files and nothing else. No API keys to provision, no MCP server to keep alive, no install script. Copy the folder and it works offline.

• Strong on edge and static sites

  Dedicated reference layers for Astro and Cloudflare Workers/Pages: island hydration against INP and LCP, the blind spots of _redirects and _headers next to Worker code, dynamic sitemaps out of D1 or KV, crawler verification at the edge.

• Staleness is tracked, not hoped away

  Every reference file carries a last_verified date that CI enforces. Corrected claims trace back to a primary source in research-notes.md, releases follow semver, and a scheduled workflow opens a re-verification issue every month.

• Technical SEO technical-seo.md

  robots.txt, sitemaps, canonical, hreflang, index coverage, redirect and status-code handling.

• Content SEO content-seo.md

  Meta tags, heading structure, internal linking, and E-E-A-T signals that reviewers can actually check.

• Structured data structured-data.md

  JSON-LD templates: Article, Product, LocalBusiness, BreadcrumbList, VideoObject, Organization, WebSite, Event.

• Core Web Vitals core-web-vitals.md

  LCP, INP and CLS — the causes, the fixes as code, and the measurement scripts to confirm them.

• AI search / GEO / LLMO ai-search.md

  AI Overviews and AI Mode, crawler control for GPTBot, ClaudeBot and Google-Extended, citation-ready content, entity clarity, information gain.

• Astro SEO astro-seo.md

  Client directives against hydration cost, @astrojs/sitemap, ClientRouter, content collections. Verified against Astro 6.

• Edge SEO edge-seo.md

  Cloudflare Workers and Pages: _redirects, _headers, X-Robots-Tag, HTMLRewriter, D1/KV sitemaps, Pages Functions.

• Audit workflow audit-workflow.md

  A staged audit process and the report format that comes out of it, so two runs on the same site are comparable.

1. 1Add the marketplace

   claude plugin marketplace add kpab/seo-mastery-agent-skills

2. 2Install the plugin

   claude plugin install seo-mastery@seo-mastery-agent-skills

Installs both the English and Japanese skills, and keeps them updatable through the plugin manager.

.claude/skills/
├── seo-mastery/            # English
│   ├── SKILL.md              # routing + overview
│   ├── technical-seo.md
│   ├── content-seo.md
│   ├── structured-data.md
│   ├── core-web-vitals.md
│   ├── ai-search.md
│   ├── astro-seo.md
│   ├── edge-seo.md
│   └── audit-workflow.md
└── seo-mastery-jp/         # Japanese (same nine files)

Fetching SKILL.md alone leaves the skill incomplete — the reference files are where the criteria live.

• Date-stamped

  Every file under .claude/skills carries last_verified in its frontmatter. CI checks it is present, valid, not in the future, and identical between the English and Japanese versions.

• Sourced

  Claims added or corrected in a verification pass are traceable to a primary source in docs/research-notes.md — the vendor documentation, not a summary of it.

• Versioned

  Semver read for a knowledge base: MAJOR for reversed guidance or a removed file, MINOR for new knowledge, PATCH for corrections and freshness. The release workflow fails if SKILL.md, both manifests, the CHANGELOG heading and the git tag disagree.

• Re-checked on a schedule

  A scheduled workflow opens a re-verification issue every month, so a stale claim surfaces as work rather than sitting quietly in a file.