Technical SEO audit across 8 categories: crawlability, indexability, security, URL structure, mobile, Core Web Vitals, structured data, JS rendering. Schema deep validation → seo-schema. AI crawlers → seo-geo-technical. Use when user says "technical SEO", "crawl issues", "robots.txt", "Core Web Vitals".
Installation
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
Technical SEO audit across 8 categories: crawlability, indexability, security, URL structure, mobile, Core Web Vitals, structured data, JS rendering. Schema deep validation → seo-schema. AI crawlers → seo-geo-technical. Use when user says "technical SEO", "crawl issues", "robots.txt", "Core Web Vitals".
allowed-tools
["WebFetch","Read"]
Technical SEO Audit
Categories
1. Crawlability
robots.txt: exists, valid, not blocking important resources
XML sitemap: exists, referenced in robots.txt, valid format
Noindex tags: intentional vs accidental
Crawl depth: important pages within 3 clicks of homepage
JavaScript rendering: check if critical content requires JS execution
Crawl budget: for large sites (>10k pages), efficiency matters
AI Crawler Management
For detailed checks, use seo-geo-technical
This skill only checks basic robots.txt configuration. For detailed AI crawler checks (GPTBot, ClaudeBot, PerplexityBot), llms.txt generation, and SSR checks, use seo-geo-technical.
2. Indexability
Canonical tags: self-referencing, no conflicts with noindex
Duplicate content: near-duplicates, parameter URLs, www vs non-www
Thin content: pages below minimum word counts per type
Pagination: rel=next/prev or load-more pattern
Hreflang: correct for multi-language/multi-region sites
Index bloat: unnecessary pages consuming crawl budget
3. Security
HTTPS: enforced, valid SSL certificate, no mixed content
Security headers:
Content-Security-Policy (CSP)
Strict-Transport-Security (HSTS)
X-Frame-Options
X-Content-Type-Options
Referrer-Policy
HSTS preload: check preload list inclusion for high-security sites
4. URL Structure
Clean URLs: descriptive, hyphenated, no query parameters for content
Hierarchy: logical folder structure reflecting site architecture
Redirects: no chains (max 1 hop), 301 for permanent moves
URL length: flag >100 characters
Trailing slashes: consistent usage
5. Mobile Optimization
Responsive design: viewport meta tag, responsive CSS
Touch targets: minimum 48x48px with 8px spacing
Font size: minimum 16px base
No horizontal scroll
Mobile-first indexing: Google indexes mobile version. Mobile-first indexing is 100% complete as of July 5, 2024. Google now crawls and indexes ALL websites exclusively with the mobile Googlebot user-agent.
6. Core Web Vitals
LCP (Largest Contentful Paint): target <2.5s
INP (Interaction to Next Paint): target <200ms
INP replaced FID on March 12, 2024. FID was fully removed from all Chrome tools (CrUX API, PageSpeed Insights, Lighthouse) on September 9, 2024. Do NOT reference FID anywhere.
CLS (Cumulative Layout Shift): target <0.1
Evaluation uses 75th percentile of real user data
Use PageSpeed Insights API or CrUX data if MCP available
7. Structured Data
Detection: JSON-LD (preferred), Microdata, RDFa
Validation against Google's supported types
See seo-schema skill for full analysis
8. JavaScript Rendering
Check if content visible in initial HTML vs requires JS
Identify client-side rendered (CSR) vs server-side rendered (SSR)
Flag SPA frameworks (React, Vue, Angular) that may cause indexing issues
Verify dynamic rendering setup if applicable
JavaScript SEO — Canonical & Indexing Guidance (December 2025)
Google updated its JavaScript SEO documentation in December 2025 with critical clarifications:
Canonical conflicts: If a canonical tag in raw HTML differs from one injected by JavaScript, Google may use EITHER one. Ensure canonical tags are identical between server-rendered HTML and JS-rendered output.
noindex with JavaScript: If raw HTML contains <meta name="robots" content="noindex"> but JavaScript removes it, Google MAY still honor the noindex from raw HTML. Serve correct robots directives in the initial HTML response.
Non-200 status codes: Google does NOT render JavaScript on pages returning non-200 HTTP status codes. Any content or meta tags injected via JS on error pages will be invisible to Googlebot.
Structured data in JavaScript: Product, Article, and other structured data injected via JS may face delayed processing. For time-sensitive structured data (especially e-commerce Product markup), include it in the initial server-rendered HTML.
Best practice: Serve critical SEO elements (canonical, meta robots, structured data, title, meta description) in the initial server-rendered HTML rather than relying on JavaScript injection.
9. IndexNow Protocol
Check if site supports IndexNow for Bing, Yandex, Naver
Supported by search engines other than Google
Recommend implementation for faster indexing on non-Google engines
Output
Technical Score: XX/100
Category Breakdown
Category
Status
Score
Crawlability
✅/⚠️/❌
XX/100
Indexability
✅/⚠️/❌
XX/100
Security
✅/⚠️/❌
XX/100
URL Structure
✅/⚠️/❌
XX/100
Mobile
✅/⚠️/❌
XX/100
Core Web Vitals
✅/⚠️/❌
XX/100
Structured Data
✅/⚠️/❌
XX/100
JS Rendering
✅/⚠️/❌
XX/100
Critical Issues (fix immediately)
High Priority (fix within 1 week)
Medium Priority (fix within 1 month)
Low Priority (backlog)
[PROTOCOL]: Update this header on changes, then check CLAUDE.md
