Technical SEO Checker

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

• Crawlability Audit: Checks robots.txt, sitemaps, crawl issues

• Indexability Review: Analyzes index status and blockers

• Site Speed Analysis: Evaluates Core Web Vitals and performance

• Mobile-Friendliness: Checks mobile optimization

• Security Check: Reviews HTTPS and security headers

• Structured Data Audit: Validates schema markup

• URL Structure Analysis: Reviews URL patterns and redirects

• 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 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:

• Site URL(s) to audit

• PageSpeed Insights screenshots or reports

• robots.txt file content

• 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

WebFetch failure handling: If WebFetch returns an empty response, HTTP error, or fewer than 300 characters (JS-rendered or access-blocked page), do not proceed with empty data. Immediately ask the user to paste the page HTML or text content directly.

Core Web Vitals via PageSpeed API (free, no key required): For steps requiring CWV data (LCP, CLS, INP, TTFB, FCP), fetch live metrics using:

• Mobile: https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url=[URL]&strategy=mobile

• Desktop: https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url=[URL]&strategy=desktop

Parse lighthouseResult.audits for largest-contentful-paint , cumulative-layout-shift , interaction-to-next-paint , server-response-time , and first-contentful-paint . If the API call fails, note which metrics are estimated vs. measured.

When a user requests a technical SEO audit:

Audit Crawlability

Crawlability Analysis

Robots.txt Review

URL: [domain]/robots.txt Status: [Found/Not Found/Error]

Current Content:

[robots.txt content]

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]

Issues Found:

• [Issue 1]

Crawl Budget Analysis

Crawlability Score: [X]/10

Audit Indexability

Indexability Analysis

Index Status Overview

Index Blockers Check

Canonical Tags Audit

Duplicate Content Issues

Indexability Score: [X]/10

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 for the performance analysis template (Step 3).

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

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

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

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

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

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

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

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

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

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

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 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 for a full worked example (cloudhosting.com technical audit) and the comprehensive technical SEO checklist.

Tips for Success

• Prioritize by impact - Fix critical issues first

• Monitor continuously - Use ~~search console alerts

• Test changes - Verify fixes work before deploying widely

• Document everything - Track changes for troubleshooting

• 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.

Reference Materials

• robots.txt Reference — Syntax guide, templates, common configurations

• HTTP Status Codes — SEO impact of each status code, redirect best practices

• Technical Audit Templates — Detailed output templates for steps 3-9 (CWV, mobile, security, URL structure, structured data, international, audit summary)

• Technical Audit Example & Checklist — Full worked example and comprehensive technical SEO checklist

Related Skills

• on-page-seo-auditor — On-page SEO audit

• schema-markup-generator — Fix schema issues

• performance-reporter — Monitor improvements

• internal-linking-optimizer — Fix link issues

• alert-manager — Set up alerts for technical issues found

• content-quality-auditor — Full 80-item CORE-EEAT audit