SEO Optimizer

Verified by Sigistry

Comprehensive SEO plugin for Claude Code. Audit, optimize, and review website content for search engines, and now make your site legible to AI answer engines too with built-in llms.txt generation and validation.

Purpose

The SEO Optimizer plugin helps developers and content creators implement SEO best practices directly from the command line. It audits existing SEO implementation, optimizes content for search, and applies precision micro-edits that improve discoverability without altering the original voice or style.

New in 1.1.0: AI discoverability. Search is no longer only ten blue links. ChatGPT, Claude, Perplexity, and Google AI Overviews read sites too, and they look for signals classic SEO ignores. The plugin now generates and validates llms.txt, checks AI-crawler access in robots.txt (GPTBot, ClaudeBot, PerplexityBot, Google-Extended), and flags content that AI crawlers cannot read. Run /seo-optimizer:llms-audit for the full pass.

Installation

/plugin marketplace add sigistry/marketplace

/plugin install seo-optimizer@sigistry

Usage

Commands

/seo-optimizer:seo-audit - SEO Compliance Audit

Perform a comprehensive SEO audit on HTML files or web applications.

# Audit a specific file
/seo-optimizer:seo-audit src/index.html

# Audit an entire directory
/seo-optimizer:seo-audit ./public

# Audit a Next.js app
/seo-optimizer:seo-audit app/layout.tsx

What it checks:

  • Essential meta tags (title, description, viewport)
  • Open Graph tags for social sharing
  • Twitter Card tags
  • Heading hierarchy (H1-H6 structure)
  • Image alt text
  • robots.txt and sitemap.xml
  • Canonical URLs
  • Structured data (Schema.org)

/seo-optimizer:seo-optimize - Content Optimization

Apply minimal, high-precision SEO edits to improve organic search performance.

# Optimize a content file
/seo-optimizer:seo-optimize content/blog/my-article.md

# Optimize an HTML page
/seo-optimizer:seo-optimize pages/about.html

What it does:

  • Enhances keyword placement naturally
  • Optimizes headings for search intent
  • Improves meta-friendly structure
  • Adds internal linking opportunities
  • Preserves original voice and tone

/seo-optimizer:seo-reviewer - Micro-Edit Review

Apply minimal SEO micro-edits as part of a content review pipeline. Stricter than optimize, with a 5% character change limit.

# Review and apply micro-edits
/seo-optimizer:seo-reviewer content/landing-page.md

Constraints:

  • Maximum 5% character change
  • No alteration of voice or narrative
  • YMYL content protection (health/finance/legal)
  • No fabrication of facts or data

/seo-optimizer:llms-audit - AI Discoverability & llms.txt

Audit whether your site is legible to AI answer engines and agents, and generate a compliant llms.txt when one is missing.

# Audit a local project (finds the web root)
/seo-optimizer:llms-audit ./

# Audit a live site
/seo-optimizer:llms-audit https://example.com

What it does:

  • Checks for a valid /llms.txt (and /llms-full.txt) per the llmstxt.org standard
  • Generates a curated llms.txt from your real pages when one is missing
  • Reports AI-crawler access in robots.txt (GPTBot, OAI-SearchBot, ClaudeBot, PerplexityBot, Google-Extended, CCBot)
  • Flags content AI crawlers cannot read (JS-only rendering, missing answer-shaped schema)

Crawler access is treated as an owner policy decision: the audit reports the tradeoff and never changes robots.txt on its own.

Skill

SEO Expert

Activate the SEO Expert skill for interactive consultation on SEO topics.

Expertise areas:

  • Technical SEO (crawlability, Core Web Vitals, structured data)
  • On-page SEO (meta tags, headings, content optimization)
  • Platform-specific SEO (Next.js, React, Vue, WordPress)
  • AI discoverability & GEO (llms.txt, AI-crawler policy, getting cited in AI answers)
  • Content strategy and search intent

Example interactions:

  • "How do I implement structured data for my blog?"
  • "What's wrong with my meta tag setup?"
  • "Help me optimize this page for Core Web Vitals"
  • "Set up an llms.txt so ChatGPT and Perplexity can read my site"
  • "Which AI crawlers is my robots.txt blocking?"

Typical Workflow

1. Audit Existing SEO

Start by auditing your current SEO implementation:

/seo-optimizer:seo-audit ./src

This generates a comprehensive report with:

  • Overall SEO score
  • Critical issues to fix immediately
  • Warnings to review
  • Passed checks
  • Prioritized recommendations

2. Fix Critical Issues

Use the SEO Expert skill to understand and fix critical issues:

User: The audit found my site is missing structured data. How do I add it?
SEO Expert: [Provides framework-specific implementation guidance]

3. Optimize Content

Run the optimizer on content pages:

/seo-optimizer:seo-optimize content/services.md

Review the changes and apply them to your files.

4. Final Review

Before publishing, run the micro-editor for final polish:

/seo-optimizer:seo-reviewer content/services.md

This applies conservative, high-precision edits that won't alter your voice.

Plugin Structure

seo-optimizer/
├── .claude-plugin/
│   └── plugin.json         # Plugin metadata
├── commands/
│   ├── seo-audit.md        # SEO compliance audit (incl. AI discoverability)
│   ├── seo-optimize.md     # Content optimization
│   ├── seo-reviewer.md     # Micro-edit review
│   └── llms-audit.md       # llms.txt audit + generator
├── skills/
│   └── seo-expert.md       # Interactive SEO consultant
└── README.md               # This file

SEO Checklist

Use this checklist alongside the plugin:

Essential Meta Tags

  • Title tag (50-60 characters)
  • Meta description (70-160 characters, optimal: 120-155)
  • Viewport meta tag
  • Canonical URL

Social Tags

  • Open Graph title, description, image, URL
  • Twitter Card tags

Structure

  • Single H1 per page
  • Proper H2-H6 hierarchy
  • Alt text on all images
  • Semantic HTML

Technical Files

  • robots.txt
  • sitemap.xml
  • Structured data (JSON-LD)

AI Discoverability

  • llms.txt at the site root (valid, curated, current)
  • llms-full.txt for docs/content-heavy sites
  • AI crawlers allowed (or intentionally blocked) in robots.txt
  • Answer-shaped content is server-rendered with FAQ/HowTo schema

Requirements

  • Claude Code CLI
  • Access to HTML/content files to audit and optimize

Framework Support

The plugin works with:

  • Static HTML/CSS sites
  • React (Create React App, Next.js)
  • Vue (Nuxt.js)
  • Angular (Universal)
  • Svelte (SvelteKit)
  • Static site generators (Gatsby, Eleventy, Hugo, Astro)
  • WordPress themes
  • Any HTML-based content

Managing the Plugin

View installed plugins

claude plugins list

Disable temporarily

claude plugins disable seo-optimizer

Re-enable

claude plugins enable seo-optimizer

Uninstall

/plugin uninstall seo-optimizer@sigistry

Contributing

Contributions are welcome! Please see the CONTRIBUTING.md guide in the main marketplace repository.

License

MIT License - see LICENSE for details.