Technical SEO Audit

Performs a deep technical SEO audit of a website, focusing on infrastructure-level issues that affect search engine crawling, indexing, and ranking. Complements seo-auditor (which covers on-page content and off-page signals) by going deeper into the technical foundation.

Prerequisites

Target website URL
agency.config.json populated (for reporting context)
WebSearch and WebFetch tools available
Optional: Google Search Console access for indexation data

Phase 0: Intake

Read agency.config.json:

agency.name -- for report branding
services[] -- to flag relevant service recommendations

Accept parameters:

url -- (required) target website root URL
depth -- (optional) quick (homepage + 5 pages), standard (up to 25 pages), deep (up to 100 pages). Default: standard
focus_areas -- (optional) array to limit scope: core-web-vitals, crawlability, indexation, structured-data, redirects, security, mobile, international. Default: all
competitor_urls -- (optional) array of competitor URLs for comparison
gsc_data -- (optional) Google Search Console export data

Phase 1: Core Web Vitals Analysis

Use WebFetch to check PageSpeed Insights API or Chrome UX Report signals:

Metrics to Assess

Metric	Good	Needs Improvement	Poor
LCP (Largest Contentful Paint)	< 2.5s	2.5-4.0s	> 4.0s
INP (Interaction to Next Paint)	< 200ms	200-500ms	> 500ms
CLS (Cumulative Layout Shift)	< 0.1	0.1-0.25	> 0.25
FCP (First Contentful Paint)	< 1.8s	1.8-3.0s	> 3.0s
TTFB (Time to First Byte)	< 800ms	800-1800ms	> 1800ms

Page Types to Test

Homepage
Category/collection page
Product/detail page
Blog/content page
Search results page (if applicable)

Analysis

For each failing metric:

ISSUE: [metric] is [value] on [page type]
IMPACT: [how this affects rankings and UX]
CAUSE: [likely technical cause based on page analysis]
FIX: [specific technical recommendation]
PRIORITY: [HIGH/MEDIUM/LOW]
EFFORT: [quick-win / medium / major-refactor]

Phase 2: Crawlability Audit

Robots.txt Analysis

Fetch and parse robots.txt
Check for overly restrictive rules blocking important content
Check for missing rules allowing crawl of admin/private pages
Verify sitemap reference is present
Check for user-agent specific rules

XML Sitemap Analysis

Fetch sitemap(s) from robots.txt or common locations (/sitemap.xml, /sitemap_index.xml)
Count total URLs
Check for:
- URLs returning non-200 status codes
- Orphaned URLs (in sitemap but not linked from site)
- Missing URLs (important pages not in sitemap)
- Last modified dates (are they accurate or all the same?)
- Sitemap file size (under 50MB, under 50,000 URLs per file)
- Proper XML formatting

Crawl Depth Analysis

Map internal link structure from homepage
Flag pages requiring 4+ clicks to reach from homepage
Identify orphan pages (no internal links pointing to them)
Check for crawl traps (infinite pagination, faceted navigation creating duplicate URLs)

Internal Linking

Check for broken internal links (404s)
Check for redirect chains in internal links
Identify pages with very few internal links (low PageRank flow)
Check for excessive internal links on single pages (>100)

Phase 3: Indexation Audit

Index Status Checks

site:domain.com search to estimate indexed pages
Compare indexed count vs sitemap count vs actual page count
Flag significant discrepancies (indexed >> actual = duplicates; indexed << actual = indexation issues)

Common Indexation Issues

Check for:

noindex meta tags on pages that should be indexed
noindex in HTTP headers (X-Robots-Tag)
Pages blocked by robots.txt that have inbound links
Thin content pages (under 300 words) that may be filtered
Duplicate title tags across multiple pages
Duplicate meta descriptions
Missing or duplicate H1 tags

Canonical Tag Audit

Every page has a canonical tag
Self-referencing canonicals on unique pages
Canonical points to correct URL (not HTTP when HTTPS, not non-www when www)
No canonical chains (A canonicals to B, B canonicals to C)
Canonical matches the version in the sitemap

Phase 4: Structured Data Validation

Check for Existing Schema

Inspect pages for JSON-LD, Microdata, or RDFa markup:

Page Type	Expected Schema	Priority
Homepage	Organization, WebSite, SearchAction	HIGH
Product	Product, Offer, AggregateRating, Review	HIGH
Collection	CollectionPage, ItemList	MEDIUM
Blog post	Article, BlogPosting, BreadcrumbList	MEDIUM
FAQ page	FAQPage	HIGH
About page	Organization, Person	LOW
Contact	LocalBusiness, ContactPoint	MEDIUM

Validation

For each schema found:

Valid JSON-LD syntax
Required properties present (per schema.org spec)
No deprecated properties
Proper nesting
Consistent with page content (no schema spam)

Missing Schema Opportunities

Flag pages where adding schema would provide rich result eligibility:

Product pages without Product schema
FAQ content without FAQPage schema
Review content without Review schema
Events without Event schema
Breadcrumbs without BreadcrumbList schema

Phase 5: Redirect Audit

Redirect Chain Analysis

Identify redirect chains (A -> B -> C) -- all should be A -> C
Identify redirect loops
Check for mixed HTTP/HTTPS redirects
Check for mixed www/non-www redirects
Verify 301 (permanent) vs 302 (temporary) usage is correct

Common Redirect Issues

Old URLs redirecting through multiple hops
Trailing slash inconsistency (some URLs with, some without)
Case sensitivity issues (uppercase URLs not redirecting to lowercase)
Parameter-based redirects missing
Deleted page 404s that should 301 to relevant alternatives

Phase 6: Security & HTTPS

Full HTTPS: no mixed content warnings
HSTS header present and correctly configured
SSL certificate valid and not expiring within 30 days
No insecure resources loaded (images, scripts, stylesheets over HTTP)
Security headers check: CSP, X-Frame-Options, X-Content-Type-Options
Cookie security: Secure flag, HttpOnly, SameSite

Phase 7: Mobile Friendliness

Viewport meta tag present and correct
No horizontal scroll on mobile viewports
Touch targets adequately sized (min 48x48px)
Font sizes readable without zooming (min 16px body text)
No intrusive interstitials blocking content
Mobile page speed (separate from desktop CWV)

Phase 8: International SEO (if applicable)

Hreflang tags present and correct
Return tags (each hreflang pair must be bidirectional)
x-default tag present
Language/region targeting consistent across pages
No conflicting canonical and hreflang signals

Phase 9: Output

Return structured JSON:

{
  "url": "https://example.com",
  "audit_date": "2026-03-13",
  "audit_depth": "standard",
  "pages_analyzed": 25,
  "overall_health_score": 72,
  "score_breakdown": {
    "core_web_vitals": 65,
    "crawlability": 80,
    "indexation": 75,
    "structured_data": 60,
    "redirects": 85,
    "security": 90,
    "mobile": 70
  },
  "critical_issues": [
    {
      "category": "core-web-vitals",
      "issue": "LCP 4.2s on product pages",
      "impact": "Ranking penalty, 53% bounce rate increase above 3s",
      "fix": "Optimize hero image: compress, add srcset, preload LCP image",
      "priority": "HIGH",
      "effort": "quick-win",
      "pages_affected": 45
    }
  ],
  "warnings": [
    {
      "category": "structured-data",
      "issue": "Product pages missing AggregateRating schema",
      "impact": "Missing star ratings in search results",
      "fix": "Add AggregateRating to Product JSON-LD",
      "priority": "MEDIUM",
      "effort": "medium"
    }
  ],
  "opportunities": [
    {
      "category": "indexation",
      "opportunity": "45 blog posts with thin content could be consolidated",
      "impact": "Reduce index bloat, concentrate PageRank",
      "effort": "major-refactor"
    }
  ],
  "competitor_comparison": {
    "our_score": 72,
    "competitor_scores": [
      {"url": "competitor1.com", "score": 68},
      {"url": "competitor2.com", "score": 81}
    ]
  },
  "recommendations_summary": [
    {"priority": 1, "action": "Fix LCP on product pages", "impact": "HIGH", "effort": "quick-win"},
    {"priority": 2, "action": "Add Product schema to all product pages", "impact": "HIGH", "effort": "medium"},
    {"priority": 3, "action": "Resolve 12 redirect chains", "impact": "MEDIUM", "effort": "quick-win"}
  ],
  "generated_at": "2026-03-13T10:00:00Z"
}

Phase 10: Report & Handoff

Present findings as a prioritized action plan:

Critical (fix immediately): Issues causing ranking loss or indexation failures
High priority (fix this week): Significant performance or schema issues
Medium priority (fix this month): Optimization opportunities
Low priority (backlog): Nice-to-haves and future improvements

If write_to_crm context exists, log the audit as a prospect touchpoint.

Example Usage

Trigger phrases:

"Run a technical SEO audit on [url]"
"Check Core Web Vitals for [url]"
"Audit the structured data on [url]"
"Check [url] for crawlability issues"
"Run a redirect chain analysis on [url]"
"Full technical SEO check on this prospect's site"
"Compare our client's technical SEO against competitors"

technical-seo-audit

SKILL.mdskills/capabilities/technical-seo-audit/SKILL.md