technical-seo-checker by aaron-he-zhu

---
name: technical-seo-checker
version: "3.0.0"
description: 'This skill should be used when the user asks to "technical SEO audit", "check page speed", "Core Web Vitals", "LCP is slow", "CLS problem", "INP issues", "crawl errors", "indexing problems", "robots.txt check", "XML sitemap errors", "hreflang issues", "canonical tag problems", "HTTPS not working", "mobile SEO", "JavaScript rendering", or "site health check". Performs comprehensive technical SEO audits: Core Web Vitals (LCP/CLS/INP/TTFB), crawlability, indexability, mobile-friendliness, HTTPS/HSTS security, URL structure, redirect chains, robots.txt, XML sitemaps, hreflang, canonical tags, and structured data validation. Produces a scored technical health report (0–100) with critical/high/medium issue triage and a prioritized implementation roadmap. Works with Google PageSpeed Insights, Google Search Console, crawl tools, or manual audit. For content element issues, see on-page-seo-auditor. For link architecture, see internal-linking-optimizer.'
license: Apache-2.0
compatibility: "Claude Code ≥1.0, skills.sh marketplace, ClawHub marketplace, Vercel Labs skills ecosystem. No system packages required. Optional: MCP network access for SEO tool integrations."
allowed-tools: WebFetch
metadata:
  author: aaron-he-zhu
  version: "3.0.0"
  geo-relevance: "low"
  tags:
    - seo
    - technical seo
    - page speed
    - core web vitals
    - crawlability
    - indexability
    - mobile-friendly
    - site speed
    - security audit
    - core-web-vitals
    - page-speed
    - lcp
    - cls
    - inp
    - ttfb
    - crawl-errors
    - robots-txt
    - xml-sitemap
    - hreflang
    - canonicalization
    - https
    - mobile-seo
    - redirect-chains
    - javascript-rendering
    - site-health
  triggers:
    - "technical SEO audit"
    - "check page speed"
    - "crawl issues"
    - "Core Web Vitals"
    - "site indexing problems"
    - "mobile-friendly check"
    - "site speed"
    - "my site is slow"
    - "Google can't crawl my site"
    - "mobile issues"
    - "indexing problems"
---

# Technical SEO Checker


> **[SEO & GEO Skills Library](https://skills.sh/aaron-he-zhu/seo-geo-claude-skills)** · 20 skills for SEO + GEO · Install all: `npx skills add aaron-he-zhu/seo-geo-claude-skills`

<details>
<summary>Browse all 20 skills</summary>

**Research** · [keyword-research](../../research/keyword-research/) · [competitor-analysis](../../research/competitor-analysis/) · [serp-analysis](../../research/serp-analysis/) · [content-gap-analysis](../../research/content-gap-analysis/)

**Build** · [seo-content-writer](../../build/seo-content-writer/) · [geo-content-optimizer](../../build/geo-content-optimizer/) · [meta-tags-optimizer](../../build/meta-tags-optimizer/) · [schema-markup-generator](../../build/schema-markup-generator/)

**Optimize** · [on-page-seo-auditor](../on-page-seo-auditor/) · **technical-seo-checker** · [internal-linking-optimizer](../internal-linking-optimizer/) · [content-refresher](../content-refresher/)

**Monitor** · [rank-tracker](../../monitor/rank-tracker/) · [backlink-analyzer](../../monitor/backlink-analyzer/) · [performance-reporter](../../monitor/performance-reporter/) · [alert-manager](../../monitor/alert-manager/)

**Cross-cutting** · [content-quality-auditor](../../cross-cutting/content-quality-auditor/) · [domain-authority-auditor](../../cross-cutting/domain-authority-auditor/) · [entity-optimizer](../../cross-cutting/entity-optimizer/) · [memory-management](../../cross-cutting/memory-management/)

</details>

This skill performs comprehensive technical SEO audits to identify issues that may prevent search engines from properly crawling, indexing, and ranking your site.

## When to Use This Skill

- Launching a new website
- Diagnosing ranking drops
- Pre-migration SEO audits
- Regular technical health checks
- Identifying crawl and index issues
- Improving site performance
- Fixing Core Web Vitals issues

## What This Skill Does

1. **Crawlability Audit**: Checks robots.txt, sitemaps, crawl issues
2. **Indexability Review**: Analyzes index status and blockers
3. **Site Speed Analysis**: Evaluates Core Web Vitals and performance
4. **Mobile-Friendliness**: Checks mobile optimization
5. **Security Check**: Reviews HTTPS and security headers
6. **Structured Data Audit**: Validates schema markup
7. **URL Structure Analysis**: Reviews URL patterns and redirects
8. **International SEO**: Checks hreflang and localization

## How to Use

### Full Technical Audit

```
Perform a technical SEO audit for [URL/domain]
```

### Specific Issue Check

```
Check Core Web Vitals for [URL]
```

```
Audit crawlability and indexability for [domain]
```

### Pre-Migration Audit

```
Technical SEO checklist for migrating [old domain] to [new domain]
```

## Data Sources

> See [CONNECTORS.md](../../CONNECTORS.md) for tool category placeholders.

**With ~~web crawler + ~~page speed tool + ~~CDN connected:**
Claude can automatically crawl the entire site structure via ~~web crawler, pull Core Web Vitals and performance metrics from ~~page speed tool, analyze caching headers from ~~CDN, and fetch mobile-friendliness data. This enables comprehensive automated technical audits.

**With manual data only:**
Ask the user to provide:
1. Site URL(s) to audit
2. PageSpeed Insights screenshots or reports
3. robots.txt file content
4. sitemap.xml URL or file

Proceed with the full audit using provided data. Note in the output which findings are from automated crawl vs. manual review.

## Instructions

When a user requests a technical SEO audit:

1. **Audit Crawlability**

   ```markdown
   ## Crawlability Analysis
   
   ### Robots.txt Review
   
   **URL**: [domain]/robots.txt
   **Status**: [Found/Not Found/Error]
   
   **Current Content**:
   ```
   [robots.txt content]
   ```
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | File exists | ✅/❌ | [notes] |
   | Valid syntax | ✅/⚠️/❌ | [errors found] |
   | Sitemap declared | ✅/❌ | [sitemap URL] |
   | Important pages blocked | ✅/⚠️/❌ | [blocked paths] |
   | Assets blocked | ✅/⚠️/❌ | [CSS/JS blocked?] |
   | Correct user-agents | ✅/⚠️/❌ | [notes] |
   
   **Issues Found**:
   - [Issue 1]
   - [Issue 2]
   
   **Recommended robots.txt**:
   ```
   User-agent: *
   Allow: /
   Disallow: /admin/
   Disallow: /private/
   
   Sitemap: https://example.com/sitemap.xml
   ```
   
   ---
   
   ### XML Sitemap Review
   
   **Sitemap URL**: [URL]
   **Status**: [Found/Not Found/Error]
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Sitemap exists | ✅/❌ | [notes] |
   | Valid XML format | ✅/⚠️/❌ | [errors] |
   | In robots.txt | ✅/❌ | [notes] |
   | Submitted to ~~search console | ✅/⚠️/❌ | [notes] |
   | URLs count | [X] | [appropriate?] |
   | Only indexable URLs | ✅/⚠️/❌ | [notes] |
   | Includes priority | ✅/⚠️ | [notes] |
   | Includes lastmod | ✅/⚠️ | [accurate?] |
   
   **Issues Found**:
   - [Issue 1]
   
   ---
   
   ### Crawl Budget Analysis
   
   | Factor | Status | Impact |
   |--------|--------|--------|
   | Crawl errors | [X] errors | [Low/Med/High] |
   | Duplicate content | [X] pages | [Low/Med/High] |
   | Thin content | [X] pages | [Low/Med/High] |
   | Redirect chains | [X] found | [Low/Med/High] |
   | Orphan pages | [X] found | [Low/Med/High] |
   
   **Crawlability Score**: [X]/10
   ```

2. **Audit Indexability**

   ```markdown
   ## Indexability Analysis
   
   ### Index Status Overview
   
   | Metric | Count | Notes |
   |--------|-------|-------|
   | Pages in sitemap | [X] | |
   | Pages indexed | [X] | [source: site: search] |
   | Index coverage ratio | [X]% | [good if >90%] |
   
   ### Index Blockers Check
   
   | Blocker Type | Found | Pages Affected |
   |--------------|-------|----------------|
   | noindex meta tag | [X] | [list or "none"] |
   | noindex X-Robots | [X] | [list or "none"] |
   | Robots.txt blocked | [X] | [list or "none"] |
   | Canonical to other | [X] | [list or "none"] |
   | 4xx/5xx errors | [X] | [list or "none"] |
   | Redirect loops | [X] | [list or "none"] |
   
   ### Canonical Tags Audit
   
   | Check | Status | Notes |
   |-------|--------|-------|
   | Canonicals present | ✅/⚠️/❌ | [X]% of pages |
   | Self-referencing | ✅/⚠️/❌ | [notes] |
   | Consistent (HTTP/HTTPS) | ✅/⚠️/❌ | [notes] |
   | Consistent (www/non-www) | ✅/⚠️/❌ | [notes] |
   | No conflicting signals | ✅/⚠️/❌ | [notes] |
   
   ### Duplicate Content Issues
   
   | Issue Type | Count | Examples |
   |------------|-------|----------|
   | Exact duplicates | [X] | [URLs] |
   | Near duplicates | [X] | [URLs] |
   | Parameter duplicates | [X] | [URLs] |
   | WWW/non-WWW | [X] | [notes] |
   | HTTP/HTTPS | [X] | [notes] |
   
   **Indexability Score**: [X]/10
   ```

3. **Audit Site Speed & Core Web Vitals** — CWV metrics (LCP/FID/CLS/INP), additional performance metrics (TTFB/FCP/Speed Index/TBT), resource loading breakdown, optimization recommendations

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the performance analysis template (Step 3).

4. **Audit Mobile-Friendliness** — Mobile-friendly test, responsive design check, mobile-first indexing verification

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the mobile optimization template (Step 4).

5. **Audit Security & HTTPS** — SSL certificate, HTTPS enforcement, mixed content, HSTS, security headers (CSP, X-Frame-Options, etc.)

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the security analysis template (Step 5).

6. **Audit URL Structure** — URL patterns, issues (dynamic params, session IDs, uppercase), redirect analysis (chains, loops, 302s)

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the URL structure template (Step 6).

7. **Audit Structured Data** — Schema markup validation, missing schema opportunities. CORE-EEAT alignment: maps to O05.

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the structured data template (Step 7).

8. **Audit International SEO (if applicable)** — Hreflang implementation, language/region targeting

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the international SEO template (Step 8).

9. **Generate Technical Audit Summary** — Overall health score with visual breakdown, critical/high/medium issues, quick wins, implementation roadmap (weeks 1-4+), monitoring recommendations

   > **Reference**: See [references/technical-audit-templates.md](./references/technical-audit-templates.md) for the audit summary template (Step 9).

## Validation Checkpoints

### Input Validation
- [ ] Site URL or domain clearly specified
- [ ] Access to technical data (robots.txt, sitemap, or crawl results)
- [ ] Performance metrics available (via ~~page speed tool or screenshots)

### Output Validation
- [ ] Every recommendation cites specific data points (not generic advice)
- [ ] All issues include affected URLs or page counts
- [ ] Performance metrics include actual numbers with units (seconds, KB, etc.)
- [ ] Source of each data point clearly stated (~~web crawler data, ~~page speed tool, user-provided, or estimated)

## Example

> **Reference**: See [references/technical-audit-example.md](./references/technical-audit-example.md) for a full worked example (cloudhosting.com technical audit) and the comprehensive technical SEO checklist.

## Tips for Success

1. **Prioritize by impact** - Fix critical issues first
2. **Monitor continuously** - Use ~~search console alerts
3. **Test changes** - Verify fixes work before deploying widely
4. **Document everything** - Track changes for troubleshooting
5. **Regular audits** - Schedule quarterly technical reviews

> **Technical reference**: For issue severity framework, prioritization matrix, and Core Web Vitals optimization quick reference, see [references/http-status-codes.md](./references/http-status-codes.md).

## Reference Materials

- [robots.txt Reference](./references/robots-txt-reference.md) — Syntax guide, templates, common configurations
- [HTTP Status Codes](./references/http-status-codes.md) — SEO impact of each status code, redirect best practices
- [Technical Audit Templates](./references/technical-audit-templates.md) — Detailed output templates for steps 3-9 (CWV, mobile, security, URL structure, structured data, international, audit summary)
- [Technical Audit Example & Checklist](./references/technical-audit-example.md) — Full worked example and comprehensive technical SEO checklist

## Related Skills

- [on-page-seo-auditor](../on-page-seo-auditor/) — On-page SEO audit
- [schema-markup-generator](../../build/schema-markup-generator/) — Fix schema issues
- [performance-reporter](../../monitor/performance-reporter/) — Monitor improvements
- [internal-linking-optimizer](../internal-linking-optimizer/) — Fix link issues
- [alert-manager](../../monitor/alert-manager/) — Set up alerts for technical issues found
- [content-quality-auditor](../../cross-cutting/content-quality-auditor/) — Full 80-item CORE-EEAT audit