SEO Technical Audit

Example output: examples/seo-technical-audit-linear-app-20260514/TECH-AUDIT.md

Technical Audit

A one-shot technical SEO audit for a domain. Discovers the URL set (XML sitemap / GSC indexed pages / DataForSEO top pages), loops DataForSEO On-Page checks over it, layers GSC indexation + sitemap truth and field Core Web Vitals, categorizes findings by area (crawlability, indexability, security, mobile, structured data, etc.), severity-sorts within each, and produces a top-10 fix list ranked by impact × effort.

The audit has a single canonical path: a single-page fast path (on_page_instant_pages + on_page_lighthouse) when the target is one URL, and a full-site path that loops those same On-Page tools over a capped, traffic-weighted URL set discovered from the sitemap, GSC, and DataForSEO. There is no hosted multi-page crawler — the crawl is rebuilt from tools the user already has.

Prerequisites

• DataForSEO MCP server connected.
• GSC (mcp__gscServer__*) recommended — it's the authoritative source for indexation status and sitemap ingestion truth on the user's own verified property. Firecrawl optional — for URL discovery (firecrawl_map) and raw HTML / JSON-LD where attributes matter.
• Claude's WebFetch tool available (used for sense-checking robots.txt and sitemap presence, and as a fallback URL-discovery / HTML source when Firecrawl is absent).
• User provides: a target domain (e.g. example.com). Optional: target country (default us), URL-ceiling override (default: top ~50–100 pages by traffic for large sites).

Optional accelerator: if you have a hosted-crawl MCP you can substitute it for the URL-discovery + per-page fetch loop (steps 1–2) — not required.

Process

1. Validate target & preflight. See skills/seo-firecrawl/references/preflight.md for the canonical 3-stage preflight (cost note, Firecrawl availability, Google APIs). Skill-specific notes:

   • Normalise domain (strip protocol, trailing slash) before continuing.
   • DataForSEO bills per call; looping on_page_instant_pages over a whole large site is the most expensive operation here. Cap to a documented top-N ceiling (default ~50–100 pages chosen by GSC/DataForSEO traffic + a sitemap sample) and say so in the deliverable. Use the documented limit/ceiling params to cap DataForSEO On-Page calls.
   • Firecrawl: optional. When available, step 8 (Modern signals checklist) runs on 5 sample URLs and /robots.txt, ~6 Firecrawl credits (hard cap). Without it, step 8 is skipped — JS-render canonical/noindex divergence, X-Robots-Tag headers, and AI-crawler robots-rule analysis are unavailable but the full technical-audit deliverable still ships. Pass --no-firecrawl to skip step 8 even when Firecrawl is available (saves credits).
   • Google APIs: tier 0 unlocks step 8b (CrUX field data); tier 1 also unlocks step 8c (per-URL GSC Inspection on top 5 traffic pages). See skills/seo-google/references/cross-skill-integration.md § "seo-technical-audit" for the full recipe and per-tier branches.

2. Discover the URL set (what to audit)

   • Single-page fast path. When the target is one URL (not a full domain), skip discovery and run mcp__dataforseo__on_page_instant_pages + mcp__dataforseo__on_page_lighthouse on that URL — single-page On-Page checks, then jump to step 7.
   • Full-site path. Build the URL set from any combination of:
     • XML sitemap — mcp__firecrawl-mcp__firecrawl_map (or WebFetch + parse /sitemap.xml, recursing sitemap-of-sitemaps). The declared page inventory.
     • GSC indexed pages — mcp__gscServer__get_search_analytics with dimensions=["page"] — the pages Google actually indexes, each with clicks/impressions for traffic-weighting.
     • DataForSEO top pages — mcp__dataforseo__dataforseo_labs_google_relevant_pages — top pages by estimated traffic.
   • Union the lists, dedupe, and cap to a top-N ceiling (default ~50–100 pages, biased toward GSC/DataForSEO traffic + a sitemap sample). State the ceiling in the deliverable.

3. Per-page technical fetch mcp__dataforseo__on_page_instant_pages (looped)

   • Loop on_page_instant_pages over the capped URL set. Each call returns status code, redirects, meta/title, headings, canonical, hreflang, structured-data presence, internal/external links, and resource counts.
   • Use mcp__dataforseo__on_page_content_parsing for main-content extraction where thin-content / duplicate checks need the body text.
   • Run mcp__dataforseo__on_page_lighthouse for lab CWV on the key pages only (homepage + top traffic pages — it's heavier per call).
   • This looped output is the audit's raw crawl: aggregate it by the skill into top-line metrics (pages fetched, health score derived from issue counts, total issues by severity) and per-category issue buckets (crawlability, indexability, mobile, security, structured data, content).

4. Derive per-issue page lists (from step 3 fields + GSC)

   • For each significant issue (severity ≥ medium, count ≥ 5), list the affected URLs straight from the on_page_instant_pages fields (e.g. pages with a noindex robots directive, a non-self canonical, a missing <title>, a redirect chain).
   • Enrich indexability buckets with mcp__gscServer__check_indexing_issues (coverage-state errors Google reports that the On-Page fetch can't see).
   • This produces the actionable fix list.

5. Cross-reference key URLs (aggregate per-URL from step 3)

   • For the top 5 pages by traffic (from mcp__gscServer__get_search_analytics clicks, or mcp__dataforseo__dataforseo_labs_google_relevant_pages, or homepage + key landing pages if no traffic data), collect all issues for those specific URLs from the looped on_page_instant_pages results.
   • This catches cases where one important page concentrates many issues.

5b. Indexation & sitemap truth (GSC) mcp__gscServer__*

• Indexation: mcp__gscServer__inspect_url_enhanced / mcp__gscServer__batch_url_inspection on the top traffic pages (indexed? coverage state? Google-chosen vs user canonical?) — see step 8c for the detailed branch.
• Sitemap status: mcp__gscServer__get_sitemaps / mcp__gscServer__list_sitemaps_enhanced / mcp__gscServer__get_sitemap_details (what Google ingested, error/warning counts). Surface ingestion errors in the Crawlability category.

6. Sense-check WebFetch

   • Fetch /robots.txt and /sitemap.xml directly.
   • Confirm the audit's findings match reality on these critical files (audits sometimes lag behind same-day deploys).
   • Extended security headers. WebFetch the homepage and 3 sample URLs (top-traffic landing pages from step 5, fall back to homepage + key landing pages if no keyword data); read response headers and flag any of:
     • csp_missing — Content-Security-Policy absent.
     • xframe_missing — X-Frame-Options absent (informational; CSP frame-ancestors supersedes).
     • xcontent_missing — X-Content-Type-Options not set to nosniff.
     • referrer_policy_missing — Referrer-Policy absent.
     • hsts_no_preload — Strict-Transport-Security present but preload directive missing AND domain not on the Chromium HSTS preload list.
   • Map findings via references/severity-mapping.md § Security and surface in evidence/02-issues-by-category/security.md (and inline into TECH-AUDIT.md's "By category → Security" section).

7. Categorize and prioritize using references/severity-mapping.md

   • Map each issue code to severity, fix, and effort estimate.
   • Score each finding: severity × affected-page-count / effort.
   • Build the top-10 fix list.

8. Modern signals checklist mcp__firecrawl-mcp__firecrawl_scrape

   • The on_page_instant_pages fetch doesn't execute JS and doesn't expose every response header per page. This step surfaces what's invisible to it.
   • If Firecrawl available (~6 Firecrawl credits, hard cap): pick 5 sample URLs from the audit — bias toward high-traffic landing pages and pages already flagged with noindex / canonical issues. For each:
     • JS-rendered canonical vs initial-HTML canonical (js_canonical_mismatch). Compare metadata.canonical (after JS render) against the canonical the audit recorded. Flag any divergence — per Google's Dec-2025 JavaScript SEO guidance, when a canonical in raw HTML differs from one injected by JS, Google MAY use either one, making canonical decisions non-deterministic. JS-injected canonical changes silently break indexing on JS-heavy sites.
     • JS-rendered noindex. Check metadata.robots for noindex after render. Catches client-side-only noindex injection that the audit can't see.
     • X-Robots-Tag header. Read response headers from metadata. Flag any noindex / nofollow / none directives at the HTTP layer.
     • Dec-2025 JS-SEO risk detection (Google's December 2025 JavaScript SEO guidance — four risks the static crawler cannot detect):
       • Risk 1 — Rendering-budget cuts (js_render_budget). Compare initial-HTML body size to rendered-HTML body size. Flag pages where rendered HTML is <50% of initial HTML size after JS execution — indicates Google may exhaust its render budget before the page's actual content loads.
       • Risk 2 — Hydration mismatch. Already detected above via js_canonical_mismatch; rationale: per the Dec-2025 guidance Google may pick either canonical, so any drift is a real-world ranking risk, not just a tidiness issue.
       • Risk 3 — CSR pitfalls (js_csr_meta_drift). Diff initial-HTML <title>, <h1>, and <meta name="description"> against the same fields in the JS-rendered DOM. Flag any divergence — Google does not reliably index content that only appears post-render, so the empty/wrong initial values may be what gets indexed.
       • Risk 4 — Soft-404 from JS errors (js_soft_404). Flag rendered pages where body text content is <500 chars but the HTTP response status is 200. This pattern indicates a JS render failure that Google treats as a soft-404 — the page returns 200 (so it's "live") but contains no real content (so it's "empty").
     • Then make one additional call: firecrawl_scrape on /robots.txt (1 credit). Parse for AI-crawler User-Agent rules — GPTBot, ClaudeBot, PerplexityBot, Google-Extended, ChatGPT-User, Bytespider, CCBot. Surface allow/disallow scope per agent.
   • If Firecrawl unavailable: skip this step. Note in TECH-AUDIT.md: Modern signals (JS canonical/noindex divergence, X-Robots-Tag, AI-crawler robots.txt rules, Dec-2025 JS-SEO risks): skipped — Firecrawl not installed.

8b. CWV field data via CrUX (only if google-api.json is present, tier ≥ 0)

• The looped on_page_lighthouse reports lab-only CWV (Lighthouse-flavoured estimates). CrUX returns actual Chrome user p75 metrics — the data Google ranks against.
• Run python3 scripts/pagespeed_check.py "https://{domain}" --crux-only --json for current p75 LCP / INP / CLS / FCP / TTFB.
• Run python3 scripts/crux_history.py "https://{domain}" --origin --json for the 25-week trend per metric (improving / stable / degrading).
• If CrUX has no field data ("insufficient data"), surface that and continue — low-traffic origins are common.
• Surface in TECH-AUDIT.md as a new section "## Core Web Vitals (field data)" with current p75 + trend per metric, source labelled "CrUX 28-day origin".

8c. Per-URL indexation status via GSC URL Inspection (only if google-api.json is present, tier ≥ 1)

• For each of the top 5 traffic pages identified in step 5 (or homepage + key landing pages if no keyword data), run: python3 scripts/gsc_inspect.py "{url}" --site-url "{config.default_property}" --json
• Capture indexStatusVerdict, coverageState, googleCanonical (vs userCanonical), and lastCrawlTime per URL.
• Cross-check against the On-Page noindex / canonical findings. If GSC reports INDEXED but the On-Page fetch flagged noindex, the fetch is stale or the directive was added recently — flag for re-audit. If GSC reports EXCLUDED for a page the On-Page fetch treats as healthy, that's a hidden indexability issue the per-page fetch can't see.
• Critical-issue elevation: any userCanonical ≠ googleCanonical divergence on a top-traffic page is added to the Top-10 fix list at Critical severity regardless of severity-mapping.md's default — Google having decided on a different canonical is a real-world ranking problem.
• If the property isn't verified in GSC for this account, surface "GSC: {domain} not verified — add it in Search Console" and skip 8c only.
• Surface in TECH-AUDIT.md as a new section "## Indexation reality check (GSC URL Inspection)" with one row per top-5-traffic URL: status / canonical-divergence / last-crawled.
• See skills/seo-google/references/cross-skill-integration.md § "seo-technical-audit" for the full recipe and failure modes.

8d. IndexNow detection WebFetch

• Detection logic — IndexNow advertises its key one of three ways. Check in this order:
  1. robots.txt hint: look in the already-fetched /robots.txt (step 6) for an IndexNow: directive or a comment referencing the key file path.
  2. Response header hint: scan response headers from the homepage WebFetch (step 6) for x-indexnow-key, x-indexnow, or x-indexnow-key-location.
  3. Conventional path probe: WebFetch /<key>.txt if a key was hinted in (1) or (2). If neither hint exists, additionally probe a small set of conventional locations only when the user's domain has signalled IndexNow elsewhere (e.g. Bing Webmaster integration disclosed in robots.txt).
• Map findings via references/severity-mapping.md § IndexNow:
  • No key advertised anywhere → indexnow_no_key (Low; informational — Bing-only benefit).
  • Key advertised but /<key>.txt content ≠ advertised key → indexnow_key_mismatch (Medium).
  • Key file present and matches but no recent submissions detected → indexnow_not_submitted_recently (Low; informational).
• Detect last-key-rotation date when possible: WebFetch the key file and read the Last-Modified response header (or fall back to the file's Date header).
• Surface in evidence/02-issues-by-category/security.md (or a new evidence/02-issues-by-category/indexnow.md if findings are non-trivial; either way, fold into TECH-AUDIT.md's "By category" section) and add a row to the TECH-AUDIT.md Modern signals section showing IndexNow status: configured (Y/N) and last-key-rotation date if detectable.

9. Synthesise TECH-AUDIT.md

Output format

Create a folder seo-technical-audit-{target-slug}-{YYYYMMDD}/ with:

seo-technical-audit-{target-slug}-{YYYYMMDD}/
├── TECH-AUDIT.md                       (synthesised top-10 fix list + category summary — primary deliverable; inlines 01-audit-summary header + the six 02-issues-by-category/* tables under "By category")
├── issues.csv                          (every issue: code, severity, count, fix, effort — load-bearing CSV engineering pastes into Jira)
├── 03-key-pages-issues.md              (top 5 traffic pages, all their issues — load-bearing reference engineering / on-call consult per-URL)
└── evidence/
    ├── 02-issues-by-category/          (raw per-category tables — preserved in case a reader wants the unmerged view)
    │   ├── crawlability.md
    │   ├── indexability.md
    │   ├── security.md
    │   ├── mobile.md
    │   ├── structured-data.md
    │   └── content.md
    ├── 04-robots-sitemap-snapshot.md   (raw fetched files — preserved for reproducibility)
    └── 05-modern-signals.md            (JS-render canonical/noindex divergence, X-Robots-Tag, AI-crawler rules — requires Firecrawl)

Top-level: TECH-AUDIT.md + issues.csv + 03-key-pages-issues.md. The audit summary header (01-audit-summary) is already in TECH-AUDIT.md's header; the six per-category tables (02-issues-by-category/*.md) are inlined under TECH-AUDIT.md's "By category" section. The raw category files, robots/sitemap snapshot, and modern-signals dump live under evidence/ for reproducibility.

TECH-AUDIT.md follows this shape:

# Technical Audit: {domain}

> Audit date {YYYY-MM-DD} · Pages crawled: {n} · Health score: {n}/100

## Summary

| Severity | Count |
|---|---|
| Critical | {n} |
| High | {n} |
| Medium | {n} |
| Low | {n} |

## Top 10 fixes (impact × effort)

| Rank | Issue | Severity | Pages | Fix | Effort |
|---|---|---|---|---|---|
| 1 | {issue name} | {severity} | {n} | {one-line fix} | {S/M/L} |
| ... |

## By category

### Crawlability ({n} issues)
- {issue name} ({n} pages) — {fix}
- ...

### Indexability ({n} issues)
- ...

### Security ({n} issues)
- ...

### Mobile ({n} issues)
- ...

### Structured data ({n} issues)
- ...

### Content ({n} issues)
- ...

### Modern signals ({n} findings — Firecrawl)
- {URL} — initial-HTML canonical `{X}` differs from JS-rendered canonical `{Y}` (`js_canonical_mismatch`)
- {URL} — JS-rendered `noindex` not visible to static crawler
- {URL} — `X-Robots-Tag: noindex` at HTTP layer
- {URL} — rendered HTML <50% of initial HTML size (`js_render_budget` — Google may stop rendering before content loads)
- {URL} — title / H1 / meta description differ between initial HTML and post-render DOM (`js_csr_meta_drift`)
- {URL} — rendered body <500 chars but HTTP 200 (`js_soft_404` — likely JS render failure, treated as soft-404 by Google)
- robots.txt — `GPTBot`: {allow / disallow `/path`}, `ClaudeBot`: {…}, `Google-Extended`: {…}, ...
- IndexNow — configured: {Y/N} · key-file: `/<key>.txt` {found / missing / mismatch} · last-key-rotation: {YYYY-MM-DD or "unknown"}
- (Or: `Modern signals: skipped — Firecrawl not installed`)

### Security headers (extended — WebFetch)

| Header | Homepage | Sample 1 | Sample 2 | Sample 3 | Issue |
|---|---|---|---|---|---|
| Content-Security-Policy | {present/absent} | … | … | … | `csp_missing` if absent |
| X-Frame-Options | {present/absent} | … | … | … | `xframe_missing` if absent (informational; CSP frame-ancestors supersedes) |
| X-Content-Type-Options | {`nosniff`/absent/other} | … | … | … | `xcontent_missing` if not `nosniff` |
| Referrer-Policy | {present/absent} | … | … | … | `referrer_policy_missing` if absent |
| HSTS preload | {preload directive Y/N · on Chromium preload list Y/N} | … | … | … | `hsts_no_preload` if not on list |

## Core Web Vitals (field data — CrUX)

| Metric | p75 (current) | 25-week trend | Threshold | Status |
|---|---|---|---|---|
| LCP | {n} ms | {improving/stable/degrading} | ≤2500 ms good · ≤4000 ms needs improvement | {pass/warn/fail} |
| INP | {n} ms | … | ≤200 ms good · ≤500 ms needs improvement | … |
| CLS | {n} | … | ≤0.1 good · ≤0.25 needs improvement | … |
| FCP | {n} ms | … | ≤1800 ms good · ≤3000 ms needs improvement | … |
| TTFB | {n} ms | … | ≤800 ms good · ≤1800 ms needs improvement | … |

Source: CrUX 28-day origin. If insufficient field data: "CrUX: insufficient data for {domain} (low-traffic origin)."
(Or: `CWV (field data): not configured — run `bash extensions/google/install.sh` for setup.`)

## Indexation reality check (GSC URL Inspection)

| URL | Status | userCanonical → googleCanonical | Last crawled |
|---|---|---|---|
| {top-traffic URL 1} | {INDEXED|EXCLUDED|...} | {URL} {→ different URL if divergent} | {YYYY-MM-DD} |
| {top-traffic URL 2} | … | … | … |
| ... |

Source: GSC URL Inspection (Tier 1). If property not verified: "GSC: {domain} not verified — add it in Search Console."
(Or: `Indexation reality check: not configured (Tier 1 setup required).`)

## Key-page deep dives

### {URL with most issues}
{n} issues found. Top fixes:
1. ...
2. ...

## Recommended cadence
Re-run this skill monthly to catch regressions, or wire `seo-drift` to baseline + diff between audits.

issues.csv columns: category,issue_code,issue_name,severity,affected_pages,suggested_fix,effort,priority_score

Tips

• DataForSEO allows up to 2,000 calls/min, 30 concurrent. Skills pace sequentially.
• The looped on_page_instant_pages fetch is the most expensive operation — cap to the documented top-N ceiling (default ~50–100 pages) and lead with the highest-traffic pages so the budget is spent where impact is highest.
• Looping On-Page over a large URL set takes time (one call per page, sequential). Lead with GSC/DataForSEO top-traffic pages so the most important pages are covered first even if you trim the tail.
• The severity scale comes from the DataForSEO On-Page issue signals (not arbitrary) — see references/severity-mapping.md so impact × effort scoring is consistent run-to-run.
• For sites with >10k pages, audit critical sections separately (scope the discovered URL set to one path prefix) rather than fetching the whole site every time.
• Pair with seo-drift for regression tracking: this skill is the snapshot, drift is the diff.
• Pair with seo-sitemap for orphan/missing-page analysis (it consumes this skill's audit data).
• Don't auto-apply fixes. The skill diagnoses; humans decide which fixes to ship and in what order.