Create a repo skill

The layout (invariants)

• .agents/skills/<kebab-name>/SKILL.md is the only canonical home for every skill — public product skills (SEO workflows customers install) and internal repo skills (agent workflows like merge-ready, papercuts, this one) alike. Users install from this tree via npx skills add every-app/open-seo.
• .claude/skills/ contains only symlinks into .agents/skills/ — one per skill that Claude Code agents working in this repo should auto-load. Never copy files: .agents/skills/ is prettier-ignored (vendored skills are hash-pinned) while .claude/skills/ is not, so a copy gets reformatted on the .claude side and the trees drift — this happened to three skills before symlinks became the rule. prettier --check . does not descend into the symlinks, so a symlink stays byte-identical to its canonical source by construction.
• Vendored skills (external origin) are hash-pinned in skills-lock.json (currently only webapp-testing, from anthropics/skills). Never hand-edit a vendored skill's content; re-vendor with the skills CLI so the lock hash stays valid.
• .agents/skills/** is part of the review control plane (see AGENTS.md): changes require explicit maintainer review via CODEOWNERS. Make the change on a branch and call it out in the PR — never treat skill edits as incidental.

Creating a skill

1. mkdir .agents/skills/<kebab-name> and write SKILL.md with frontmatter:

   ---
   name: <kebab-name>            # must match the directory name
   description: <what it does + explicit "use when ..." triggers>
   metadata:
     internal: true              # ONLY for internal repo skills — omit for product skills
   ---
   

2. Decide which kind it is:

   • Internal repo skill (agent/dev workflow): set metadata.internal: true. Do NOT register it on any public surface. If repo agents should auto-load it, add the mirror symlink:

     ln -s ../../.agents/skills/<name> .claude/skills/<name>
     

   • Public product skill (a customer-facing SEO workflow): no internal flag, usually no .claude/skills symlink (repo agents don't need customer workflows). A public skill is auto-served to SAM, the live in-app agent — the marking is fail-open, so a missing internal: true ships repo-dev instructions to end users. Give it the standard "Project context" preamble (copy a sibling like seo-audit) with the skill's required sections, and register it everywhere users discover skills:

     • src/server/features/sam/samSkills.test.ts — add the name to the pinned public roster (the test fails otherwise; that failure is the guard)
     • web/content/docs/skills/<name>.mdx — docs page (mirror a sibling like competitor-analysis.mdx: what it does, when to use it, what you get back, how to get the best result)
     • web/content/docs/skills/index.md — bullet in the right workflow section
     • web/content/docs/skills/meta.json — nav entry
     • src/routes/_app/ai.tsx — SKILL_NAMES
     • .agents/skills/seo-coach/SKILL.md — one line in the "What each workflow does" roster
     • plugins/openseo/skills/<name> — add the skill to the skills list in scripts/sync-plugin-skills.mjs, then run pnpm sync-plugin-skills (this directory holds real copies, not symlinks — the Claude Code and Codex plugins bundle from here, and Codex's installer silently skips symlinked files, so a symlink would ship a skill-less plugin). pnpm ci:check re-runs the sync and fails on drift, so a missed update here is caught, but the skill count and roster below are prose and aren't checked — update them by hand: both plugins/openseo/*/plugin.json description fields, the Codex manifest's interface.longDescription, and the skill lists in web/content/docs/claude-code-plugin.md and web/content/docs/codex-plugin.md
     • Optional: web/src/lib/feature-pages.ts and web/content/docs/skills/setup.md if it deserves marketing/setup placement

3. If the skill references MCP tools, use exact tool names and keep them in sync with src/server/mcp/server.ts — the tool names in skills are load-bearing for agents following them. For public skills also check src/server/features/sam/samChatTools.ts: SAM's toolset is a curated subset, and a skill step that names a tool SAM lacks dead-ends in the in-app agent.

4. pnpm format:write (covers the docs pages; .agents/skills itself is intentionally untouched), then commit. Skill prose follows openseo-review-web-content standards when public.

Sync check (run when in doubt, and after any skill change)

for d in .claude/skills/*/; do n=$(basename "$d")
  [ -L "${d%/}" ] || echo "DRIFT RISK — not a symlink: $n"
  [ -e ".agents/skills/$n" ] || echo "BROKEN — no canonical source: $n"
done

Anything flagged: move the canonical content to .agents/skills/<name>/ (reconciling differences deliberately — diff both sides first, newest intent wins), delete the .claude copy, and replace it with the symlink.