SEO Audit 2026

You produce a comprehensive SEO audit that grades a site on the 2026 ranking surface — classic Google + the AI engines (ChatGPT browsing, Perplexity, Claude, Gemini, Google AI Overviews, Bing Copilot). Output is a single prioritized report, not a 200-item checklist dump.

The reality of 2026 SEO:

• AI Overviews handle 30%+ of informational queries with zero-click answers.
• 96% of AI Overview citations come from strong-E-E-A-T sources.
• Core Web Vitals INP < 200ms replaced FID as a ranking signal.
• Server-side rendering is non-negotiable — AI crawlers don't execute JS.
• Entity density predicts citations more than keyword density.

============================================================ === PRE-FLIGHT ===

Verify:

• Site URL (root domain).
• Access level — what you can actually fix vs only audit. If no CMS access, output read-only audit + remediation steps.
• Tools available — curl, playwright/puppeteer for render diffs, Lighthouse CLI for CWV, jq for JSON parsing. Install missing tooling or fall back to web-based equivalents.
• Target queries / pages — 5-10 priority queries OR top pages from Search Console.
• Crawl budget consent — full audit may crawl up to 1000 pages. Respect robots.txt; obey rate limits (default 1 req/sec).

Recovery:

• If user doesn't have target queries, derive from <title> tags of top nav + top 10 referrer pages.
• If full crawl is impossible (auth-walled site), audit the public surface + provide a sitemap-based audit for internal pages.

============================================================ === PHASE 1: CRAWL & INDEX AUDIT ===

Most ranking issues in 2026 trace back to crawl/index — audit before optimizing content.

Check:

1. robots.txt parity — fetch as Googlebot, GPTBot, PerplexityBot, ClaudeBot. Identical access? Flag any bot-specific blocks.
2. Sitemap correctness — fetch /sitemap.xml. Verify each listed URL returns 200, has lastmod, isn't noindex.
3. Canonical chain — for each page, follow rel=canonical. Catch self-canonical errors, redirect chains, conflicting hreflang.
4. Indexability — <meta name="robots">, X-Robots-Tag headers. Spot pages set to noindex unintentionally.
5. HTTP status distribution — count 200/301/302/404/410/500. Excessive 302→301 chains hurt; soft-404s (200 status with empty content) are the silent killer.
6. Pagination & faceted nav — are search/filter URLs canonicalized to parent OR noindexed?

Generate seo/crawl_report.md with the index status of every important URL.

VALIDATION: Every URL in the report has a definitive status (Indexable / Blocked / Redirected / Error). No "unknown" rows.

FALLBACK: If crawl is rate-limited mid-run, persist partial results and resume later.

============================================================ === PHASE 2: AI CRAWLER PARITY ===

(See geo-optimize Phase 1 for full detail.)

Run the user-agent matrix test. Diff rendered (Playwright) vs static (curl as GPTBot, PerplexityBot, OAI-SearchBot, ClaudeBot, Claude-Web, Google-Extended, Applebot-Extended).

P0 if any AI bot sees < 50% of the rendered text or schema is missing in static HTML.

VALIDATION: Parity report contains a row per page × per bot with content diff %.

============================================================ === PHASE 3: CORE WEB VITALS (2026 THRESHOLDS) ===

Run Lighthouse CI for each priority URL on both mobile and desktop. Capture:

• LCP (Largest Contentful Paint): < 2.5s (good), 2.5–4.0s (needs improvement), > 4.0s (poor)
• INP (Interaction to Next Paint): < 200ms (good), 200–500ms (needs improvement), > 500ms (poor) — REPLACED FID in March 2024
• CLS (Cumulative Layout Shift): < 0.1 (good), 0.1–0.25 (needs improvement), > 0.25 (poor)
• TTFB (Time to First Byte): < 0.8s (good)
• Total Blocking Time (lab proxy for INP)

For each fail, generate a specific fix:

• LCP fail: preload hero image, eliminate render-blocking CSS/JS, use modern image formats (AVIF/WebP), CDN for hero.
• INP fail: split long tasks, defer non-critical JS, debounce input handlers, use requestIdleCallback.
• CLS fail: explicit width/height on images, reserve space for ads, avoid font-swap layout jump (use font-display: optional or size-adjust).

VALIDATION: Each fail has a concrete code-level fix, not "improve performance."

============================================================ === PHASE 4: ON-PAGE AUDIT ===

Per priority URL, check:

• Title tag: 30–60 chars, unique site-wide, includes target query naturally (not stuffed), brand at end.
• Meta description: 120–160 chars, action-oriented, includes primary entity. Note: AI Overviews often pull from H1+first paragraph, not meta — but meta still drives SERP CTR for classic search.
• H1: exactly one per page, contains primary entity.
• Heading hierarchy: H1 → H2 → H3 (no skipping levels). Each H2 is a question or noun phrase that maps to a search intent.
• Image alt text: every content image has descriptive alt (not "image1.jpg" or empty).
• Internal linking: each priority page has ≥ 3 inbound internal links from contextually related pages. Anchor text varied (not all "click here").
• Outbound citations: at least 2 outbound links to authoritative third-party sources (E-E-A-T signal — AI engines mirror your citation behavior).
• First paragraph: states the answer to the page's primary query in plain language within the first 80 words. AI engines extract this as the citation snippet.

Generate seo/onpage_report.md per-URL.

VALIDATION: Report flags specific elements, not just "needs work."

============================================================ === PHASE 5: SCHEMA & ENTITY AUDIT ===

(Delegated to geo-optimize Phases 3 + 4.)

For each priority page, audit JSON-LD coverage and entity density. Generate missing schema. Recommend entity additions to hit ≥ 15 recognized entities per pillar page.

VALIDATION: Per-page entity count and schema validation status.

============================================================ === PHASE 6: CONTENT QUALITY & E-E-A-T ===

Per priority page:

• Author byline present and linked to /author/{slug}?
• Author Person page exists with bio + sameAs to LinkedIn / Wikidata / X / Crunchbase?
• Last-updated date visible in DOM and in Article schema dateModified?
• Original content markers — original screenshots / data / interviews / first-hand experience? (Not just rewritten generic content.)
• Citations within body to primary sources?
• HTTPS, no mixed content, valid SSL cert?
• About / Contact / Privacy pages present and linked from footer? (Trust signal.)

Generate seo/eeat_report.md with per-page and per-author scores.

VALIDATION: Each author has either a complete Person profile (5+ checkboxes pass) or a clear remediation list.

============================================================ === PHASE 7: COMPETITIVE GAP ===

For each priority query:

1. SERP scrape top 10 organic + top 5 AI Overview citations (note: those overlap ~70%).
2. Extract competitor entities, headings, schema types, word count.
3. Diff vs the user's page: entities they cite that you don't, headings they cover that you don't, schema types they have that you don't.
4. Output as a per-query gap matrix.

VALIDATION: Per-query gap report identifies at least 3 concrete additions (entities or sections) to add.

FALLBACK: If SERP scraping is rate-limited, fall back to manual top-3 analysis via the user's browser (instruct them, don't claim full coverage).

============================================================ === PHASE 8: PRIORITIZED PUNCH LIST ===

Single output seo/audit_report.md ranking findings:

# SEO Audit — {site} — {date}

## Executive Summary

- Indexability: {green/yellow/red} ({N} pages indexable / {M} blocked)
- AI Crawler Parity: {green/yellow/red} ({N} priority pages pass)
- Core Web Vitals: {N/M priority pages passing all 3}
- Schema Coverage: {N%} of priority pages have complete schema
- Entity Density: {N/M priority pages ≥15 entities}
- E-E-A-T: {N/M pages have linked author Person entity}

## P0 — Blocking Issues

- [ ] Site renders client-side, GPTBot sees empty HTML. Move /blog/\* to SSR via Next.js getServerSideProps OR pre-render via next-build.
- [ ] Missing Organization schema on homepage. (Generate JSON-LD — see fix snippet below.)

## P1 — High-Impact Fixes

- [ ] 6 of 10 priority pages fail INP > 500ms. Defer analytics.js and reduce main-thread blocking in checkout.js.
- [ ] 4 of 10 priority pages have < 15 entities. Add brand + product entity mentions per page (specifics in entity_audit.md).

## P2 — Medium-Impact

- [ ] No llms.txt at root.
- [ ] FAQPage schema missing on 3 pages with FAQ sections.

## P3 — Polish

- [ ] 14 images missing alt text in /blog/\*.

## Re-audit Checklist

After fixes, re-run with `/seo-audit-2026 {site}` and verify P0/P1 items move to ✅.

VALIDATION: Punch list ranked by impact, capped at top 20 items. Each P0/P1 includes a code-level fix or precise file path.

============================================================ === SELF-REVIEW ===

Score 1–5:

• Complete: All 8 phases ran? AI crawler parity tested? CWV measured on both mobile + desktop?
• Robust: Handled CSR sites, paywalled sites, rate limits, missing tools?
• Clean: Punch list is prioritized, not a 200-item dump?
• 2026-current: References INP (not FID), AI Overview citations, llms.txt, entity density, E-E-A-T binary gating? Doesn't recommend obsolete tactics (keyword density tuning, exact-match anchors at scale, doorway pages)?

Most common gap: failing to test AI crawler parity AND not measuring INP. These are the two table-stakes items that catch teams still running 2023-era audits.

============================================================ === LEARNINGS CAPTURE ===

Append to ~/.claude/skills/seo-audit-2026/LEARNINGS.md:

<YYYY-MM-DD> — <site, vertical, framework>

• What worked: <approach that produced clean output>
• What was awkward: <retry/manual fix needed>
• Suggested patch: <concrete improvement>
• Verdict: [Smooth / Minor friction / Major friction]

============================================================ === STRICT RULES ===

• Never use FID. It was retired March 2024. Use INP.
• Never recommend keyword density tuning. Entity density and topical authority are the modern signals.
• Never dump a 200-item checklist. Prioritize.
• Never claim "SEO complete" without AI crawler parity + schema validation + entity audit.
• Never overlook E-E-A-T author entity. 96% of AI citations come from strong-EEAT sources — it's a gate, not a polish.
• If the user only wants the AI search portion, route to /geo-optimize instead of running the full classic audit.