GTM Audit

A one-time audit of a Google Tag Manager container. GTM rarely fails loudly — it fails as a duplicate GA4 tag double-counting conversions, a tag with no trigger that never fires, or analytics tags firing before consent. This skill reads the container and finds those.

Requires: Cogny Agent subscription ($9/mo) — Sign up

Prerequisites Check

If mcp__cogny__google_tag_manager__tool_list_containers is not available:

This skill requires Cogny's Google Tag Manager MCP server.

1. Sign up at https://cogny.com/agent
2. Connect your GTM account
3. Add Cogny to your .mcp.json (see the repo README)
4. Restart Claude Code

Stop here if the tools are missing.

Usage

/gtm-audit — full container audit /gtm-audit tags — tag health only /gtm-audit triggers — trigger coverage only /gtm-audit consent — Consent Mode wiring only

Steps

1. Account & container discovery

tool_list_accounts
tool_list_containers   (account_id)

If multiple containers exist, ask which to audit. Note the container type (web vs server) — this audit targets web containers.

2. Tag inventory

tool_list_tags         (account_id, container_id, workspace_id)

For tags that need detail, call tool_get_tag. Bucket every tag by type (GA4 config, GA4 event, Google Ads conversion, Google Ads remarketing, Floodlight, custom HTML, third-party).

Flag:

• Paused tags still sitting in the container (dead weight, or accidentally off)
• More than one GA4 configuration tag for the same Measurement ID — the classic double-counting bug
• Multiple tags sending the same event to the same destination
• Custom HTML tags doing what a native tag template should do (fragile, slow)
• Google Ads conversion tags with no conversion label / ID set

3. Trigger coverage

tool_list_triggers     (account_id, container_id, workspace_id)

Cross-reference every tag's firingTriggerId against the trigger list.

Flag:

• Tags with no firing trigger — they will never fire (orphaned)
• Triggers attached to no tag — dead triggers
• All Pages triggers on conversion or event tags (should fire on a specific event)
• Click / form triggers with no conditions (fire on every click — noisy, wrong data)

4. Variable hygiene

tool_list_variables    (account_id, container_id, workspace_id)

Flag:

• Data Layer Variables referenced by tags but not defined
• Defined variables referenced by nothing (clutter)
• No version of the consent-state variables if Consent Mode is expected

5. Consent Mode v2

Inspect tags and the container setup for Consent Mode wiring.

Flag:

• Analytics / Ads tags firing with no consent check — a compliance and data risk in the EEA and UK
• No consent initialization (default denied state) before tags load
• ad_storage / analytics_storage / ad_user_data / ad_personalization not all handled

6. GA4 wiring correctness

For each GA4 event tag (tool_get_tag):

Flag:

• Event tags not referencing the GA4 config tag (or no config tag at all)
• Event names that break GA4 rules — uppercase, spaces, reserved prefixes, >40 chars (cross-reference the /ga4-events conventions)
• Ecommerce event tags not reading the ecommerce object from the data layer
• Missing parameters on key conversion events (value, currency, transaction_id)

7. Naming & workspace status

tool_get_workspace_status   (account_id, container_id, workspace_id)

Flag:

• Unpublished changes sitting in the workspace — live site is behind the container
• No naming convention (GA4 - Event - purchase style) — unmaintainable at scale
• Many open workspaces (merge-conflict risk)

8. Score and report

GTM Audit — [Container Name]
Container Health Score: X/100

Score breakdown:
  Tag health ......... X/25   (duplicates, orphans, paused)
  Trigger coverage ... X/20
  GA4 wiring ......... X/20
  Consent Mode ....... X/20
  Hygiene ............ X/15   (naming, variables, workspace)

Inventory: X tags · X triggers · X variables  ·  Unpublished changes: [yes/no]

🔴 Critical   — duplicate GA4 config, tags firing before consent
🟡 Important  — orphaned tags, bad event names, missing parameters
🟢 Optimization — naming, unused variables, custom HTML to native

Top 3 Actions:
1. [Highest impact]
2. ...
3. ...

9. Record findings

{
  "title": "Two GA4 configuration tags for G-XXXX — every page view counted twice",
  "body": "'GA4 - Config' and 'GA4 Base (old)' both load Measurement ID G-XXXX on All Pages. GA4 is counting every page_view and session twice, inflating traffic and deflating conversion rate. Pause the older tag and republish.",
  "action_type": "tag_fix",
  "expected_outcome": "Accurate GA4 traffic and conversion-rate numbers",
  "estimated_impact_usd": 0,
  "priority": "critical"
}

Action types: tag_fix, trigger_fix, consent_configuration, container_hygiene, ga4_wiring.

Critical rules

1. Duplicate GA4 config tags and pre-consent firing are always critical — they corrupt data and create compliance exposure.
2. An orphaned tag fires nothing — say which tags are dead and why.
3. Quote real numbers: tag/trigger/variable counts, the specific tag names.
4. Read-only. Never edit or publish the container — surface and recommend.