astro-seo

astro-seo is a skill for Claude Code, Codex from jdevalk/skills. It costs 105 tokens per session (4,833 once invoked), scanned A, original, MIT.

An SEO audit and improvement guide for Astro websites. Astro is a tool for building websites, while SEO improves how pages are understood and shown by search engines.

In plain words
What is it for?
Use it to audit and improve an Astro project, including JSON-LD, sitemaps, IndexNow, Open Graph previews, language versions, agent discovery, and search analytics.
Why use it?
It finds gaps in page metadata, structured data, content, navigation, performance, indexing, redirects, analytics, and related search setup.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/jdevalk/skills/astro-seo
Any agent
npx skills add jdevalk/skills --skill astro-seo
Clone the repo
git clone --depth 1 https://github.com/jdevalk/skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for astro-seo

README.md
[![agentmods](https://agentmods.dev/badge/skills/jdevalk/skills/astro-seo.svg)](https://agentmods.dev/skills/jdevalk/skills/astro-seo)
Your own site
<a href="https://agentmods.dev/skills/jdevalk/skills/astro-seo"><img src="https://agentmods.dev/badge/skills/jdevalk/skills/astro-seo.svg" alt="Measured on agentmods" height="20"></a>
Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,833 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00105 $0.04833
Opus 5 $0.00053 $0.02416
Sonnet 5 $0.00021 $0.00967
Haiku 4.5 $0.00011 $0.00483

Measured 5d ago against content hash 58ab70dc056c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

astro-seo scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

- **Should** — `lastmod` populated from git commit timestamps, not frontmatter dates or CI file timestamps. `@jdevalk/astro-seo-graph` ≥ 1.4.0 exports `gitLastmod(filePath, { excludeCommits, depth })` for this — it retur
astro-seo/SKILL.md · 212 lines

How it starts

The opening of the file, as written. The whole thing — 212 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Astro SEO

Audits and improves the SEO setup of an Astro site against the full stack described in Astro SEO: the definitive guide. The skill covers nine areas — technical foundation, structured data, content, site structure, performance, sitemaps and indexing, agent discovery, redirects, and analytics — and produces drop-in code for anything missing or weak.

The opinionated spine of this skill is @jdevalk/astro-seo-graph. Most of the fixes route through it. If the project doesn't use it yet, installing it is the first recommendation.

Code recipes live in AGENTS.md — read it when you need to implement a specific fix. This file has the workflow and audit checklist.

Workflow

  1. Detect the project — confirm this is an Astro site and understand its shape.
  2. Audit — score nine categories and produce actionable findings.
  3. Improve — generate or modify files to close the gaps. Recipes are in AGENTS.md.
  4. Metadata pass — invoke metadata-check on every short string the skill generated (titles, descriptions, schema description fields, FAQ answers, frontmatter excerpts).
  5. Verify — run the build, check validations pass, remind the user about non-file tasks (Search Console, Bing Webmaster Tools, IndexNow key verification).

Phase 0: Detect the project

Confirm the basics before auditing:

  • astro.config.mjs / astro.config.ts exists.
  • package.json has astro as a dependency.
  • site: is set in astro.config — canonicals, sitemaps, and OG image URLs all derive from this. If it's missing, empty, or http://localhost, flag it as a blocking issue before anything else. This is the single most common misconfiguration.
  • Content collections in src/content/ (or legacy src/pages/ markdown).
  • Deployment target — read package.json, vercel.json, netlify.toml, wrangler.toml, or public/_headers to determine the host. This drives redirect and header syntax in Phase 2.
  • Is @jdevalk/astro-seo-graph already installed? If yes, record the version and which features are wired (grep for <Seo, seoGraph(, createSchemaEndpoint, createSchemaMap, FuzzyRedirect, createIndexNowKeyRoute, createMarkdownEndpoint, createApiCatalog, gitLastmod). Check the installed version against the latest on npm with npm view @jdevalk/astro-seo-graph version. If the project is behind, recommend an upgrade in Phase 2 before auditing feature gaps — the package ships new defaults and fixes regularly, and an outdated version is a plausible cause for any audit finding. Phase 2 branches on this.
  • Is the site multilingual? Check for i18n in astro.config or multiple locale directories under src/content/. If yes, hreflang matters; if no, skip it.

Read the full file on GitHub · 212 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 212 lines · 105 tokens per session scan A 58ab70dc056c

Subscribe to this mod's changes

astro-seo is a skill published in the GitHub repository jdevalk/skills (97 stars, last pushed 2mo ago), licensed MIT. It adds 105 tokens to every session and 4,833 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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