Technical SEO audit across 8 categories: crawlability, indexability, security, URL structure, mobile, Core Web Vitals, structured data, and JavaScript rendering. Use when user says "technical SEO", "crawl issues", "robots.txt", "Core Web Vitals", "site speed", or "security headers".
Installation
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Technical SEO audit across 8 categories: crawlability, indexability, security, URL structure, mobile, Core Web Vitals, structured data, and JavaScript rendering. Use when user says "technical SEO", "crawl issues", "robots.txt", "Core Web Vitals", "site speed", or "security headers".
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
As of 2025-2026, AI companies actively crawl the web to train models and power AI search. Managing these crawlers via robots.txt is a critical technical SEO consideration.
Known AI crawlers:
Crawler
Company
robots.txt token
Purpose
GPTBot
OpenAI
GPTBot
Model training
ChatGPT-User
OpenAI
ChatGPT-User
Real-time browsing
ClaudeBot
Anthropic
ClaudeBot
Model training
PerplexityBot
Perplexity
PerplexityBot
Search index + training
Bytespider
ByteDance
Bytespider
Model training
Google-Extended
Google
Google-Extended
Gemini training (NOT search)
CCBot
Common Crawl
CCBot
Open dataset
Key distinctions:
Blocking Google-Extended prevents Gemini training use but does NOT affect Google Search indexing or AI Overviews (those use Googlebot)
Blocking GPTBot prevents OpenAI training but does NOT prevent ChatGPT from citing your content via browsing (ChatGPT-User)
~3-5% of websites now use AI-specific robots.txt rules
Example — selective AI crawler blocking:
# Allow search indexing, block AI training crawlers
User-agent: GPTBot
Disallow: /
User-agent: Google-Extended
Disallow: /
User-agent: Bytespider
Disallow: /
# Allow all other crawlers (including Googlebot for search)
User-agent: *
Allow: /
Recommendation: Consider your AI visibility strategy before blocking. Being cited by AI systems drives brand awareness and referral traffic. Cross-reference the seo-geo skill for full AI visibility optimization.
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
