our-claude-skills/custom-skills/60-gtm-audit/code/SKILL.md

name, description

name

description

gtm-audit

Automated GTM audit and analysis. Scans websites for tracking coverage, compares against GTM container config, identifies gaps, and reports to Notion. Uses Chrome DevTools MCP for browser inspection and DTM Agent MCP for container operations. Triggers on "GTM audit", "audit website", "scan page", "check tracking", "tracking coverage", "gap analysis", "site audit", "tag firing check". NOT for creating/modifying tags (use gtm-editor) or validating/QA (use gtm-validator).

GTM Audit Skill

Analyze GTM implementations by scanning websites and comparing against container configuration.

Available Tools

Browser Inspection (Chrome DevTools MCP)

• navigate_page — Load target URL
• evaluate_script — Capture dataLayer, detect GTM containers, check JS globals
• list_network_requests — Capture tag firing network requests
• take_screenshot — Document page state
• click / hover — Simulate user interactions
• list_console_messages — Check for JS errors

GTM Container (DTM Agent MCP)

• dtm_status — Check auth and active container
• dtm_list_tags / dtm_list_triggers / dtm_list_variables — Get container config
• dtm_audit_scan — Scan page with collected data (returns structured PageData)
• dtm_audit_gap — Run gap analysis (returns GapReport with OK/MISSING/ORPHAN)

Reporting (Notion MCP)

• Write findings to GTM Audit Log: collection://2cf581e5-8a1e-815a-a7f8-000b88b93585

4 Audit Modes

Mode A: Page Scan (/gtm-audit scan <url>)

Quick single-page diagnostics. No GTM container needed.

1. navigate_page to URL, wait for load
2. evaluate_script: capture dataLayer

   JSON.stringify(window.dataLayer || [])
   

3. evaluate_script: detect GTM containers

   (function(){var s=document.querySelectorAll('script[src*="googletagmanager.com/gtm.js"]');var ids=[];s.forEach(function(el){var m=el.src.match(/id=(GTM-[A-Z0-9]+)/);if(m)ids.push(m[1]);});return JSON.stringify(ids);})()
   

4. evaluate_script: detect tracking pixels

   (function(){var f=[];if(window.fbq)f.push('Meta Pixel');if(window.gtag)f.push('GA4');if(window.clarity)f.push('Clarity');if(window.kakaoPixel)f.push('Kakao');if(window.wcs)f.push('Naver');if(window.ttq)f.push('TikTok');return JSON.stringify(f);})()
   

5. list_network_requests — filter for tag domains
6. Call dtm_audit_scan with collected html, network_requests, datalayer_json
7. Report findings

Mode B: Site Audit (/gtm-audit site <url>)

Full website coverage audit with auto-discovery.

1. Navigate to root URL
2. evaluate_script: extract all internal links
3. Classify pages by type (home, product, service, form, blog, about)
4. For each page type: run Mode A scan
5. Build coverage matrix (page type × event × platform)
6. Run Mode C gap analysis against container
7. Write comprehensive report to Notion

Mode C: Gap Analysis (/gtm-audit gap <url>) — MOST IMPORTANT

Compare GTM container config against actual tag firing.

1. dtm_status — verify auth and active container
2. dtm_list_tags + dtm_list_triggers — get expected configuration
3. navigate_page to URL
4. evaluate_script — capture dataLayer
5. list_network_requests — capture actual tag firings
6. Call dtm_audit_gap with network_requests
7. Analyze gaps: MISSING (in GTM, not firing), ORPHAN (firing, not in GTM)
8. Write to Notion GTM Audit Log

Mode D: Tag Design (/gtm-audit design <url>)

AI-powered analysis of what SHOULD be tracked on a page.

1. navigate_page to URL
2. take_screenshot — visual reference
3. evaluate_script — inspect DOM: forms, buttons, links, product elements
4. evaluate_script — capture existing dataLayer schema
5. dtm_list_tags — check existing configuration
6. Design recommendations: which events, triggers, variables are needed
7. Output as structured blueprint (hand off to gtm-editor for implementation)

Detection Patterns

Cloudflare Zaraz Proxy

URLs with /1tbv/ path proxy GA4/Ads through the site's domain:

https://site.com/1tbv/ag/g/c?tid=G-XXXXX → GA4
https://site.com/1tbv/ag/g/c?tid=AW-XXXXX → Google Ads

Server-Side GTM (sGTM)

Custom subdomains: stms.*, sgtm.*, ss.*, tag.*

https://stms.site.com/g/collect?tid=G-XXXXX → GA4 via sGTM

GA4 Multiple Endpoints

One GA4 page_view fires to multiple endpoints — this is normal:

• google-analytics.com/g/collect
• analytics.google.com/g/s/collect
• stats.g.doubleclick.net/g/collect
• www.google.com/ccm/collect (Consent Mode)
• Zaraz proxy endpoints

Notion Report Fields

Field	Value
Site	domain name
URL	full URL
Container IDs	GTM-XXXXX
Audit Status	Pass / Warning / Fail
GTM Status	Installed / Not Found / Multiple Containers
Tags Fired	[GA4, Google Ads, Meta Pixel, Kakao, Naver, ...]
Journey Type	full / pageview / scroll / form / checkout / datalayer
Critical Issues	count
Issues Count	count
Summary	AI-generated findings

Rules

• Always check dtm_status before gap analysis
• Wait for page to fully load before capturing network requests
• Use evaluate_script to check consent mode before interpreting missing tags
• Orphan count may be high due to GA4 multi-endpoint — note this in reports
• In Mode D (tag design), check elements for id attributes — if missing, recommend adding IDs before designing CSS-based triggers. Suggest naming: [section]-[element]-[action]
• Hand off tag creation work to gtm-editor skill
• Hand off QA/validation work to gtm-validator skill