GA4 Audit

A one-time audit of a Google Analytics 4 property — configuration and data quality. GA4 collects data the moment the tag fires, but most properties quietly leak trust: unmarked key events, PII in parameters, no Ads link, (not set) traffic. This skill finds those before they corrupt a quarter of reporting.

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

Prerequisites Check

If mcp__cogny__google_analytics_4__tool_get_property is not available:

This skill requires Cogny's Google Analytics 4 MCP server.

1. Sign up at https://cogny.com/agent
2. Connect your GA4 property
3. Add Cogny to your .mcp.json (see the repo README)
4. Restart Claude Code

Stop here if the tools are missing.

Usage

/ga4-audit — full property audit /ga4-audit config — property + stream + link settings only /ga4-audit events — events, key events, custom dimensions only /ga4-audit data-quality — (not set), PII, anomaly checks only

Steps

1. Property discovery

tool_list_account_summaries
tool_get_property        (property_id)

Record: time zone, currency, industry category, data retention setting, and property type. Flag data retention left at the 2-month default — it should be 14 months so year-over-year exploration works.

2. Data streams

tool_list_data_streams   (property_id)

Flag:

• Multiple web streams for one site (splits data, double-counts users)
• Enhanced measurement off, or measuring events the team doesn't actually want
• Missing iOS/Android streams for a business that has apps

3. Key events (conversions)

tool_list_conversion_events   (property_id)

Flag:

• No key events configured — Ads bidding and GA4 reporting both lose their anchor
• Key events marked on noisy automatic events (page_view, scroll) — inflates the conversion count and misleads everyone
• Obvious business goals not marked as key events (e.g. generate_lead, purchase, sign_up)
• More than ~10–15 key events — when everything is a conversion, nothing is

4. Custom dimensions & metrics

tool_list_custom_dimensions   (property_id)
tool_list_custom_metrics      (property_id)
tool_get_metadata             (property_id)

Flag:

• Event parameters collected by the tag but never registered as custom dimensions (the data is invisible in reports) — compare get_metadata against what the streams send
• Approaching the 50 event-scoped / 25 user-scoped dimension limits
• High-cardinality registered dimensions (timestamps, IDs) — they cause (other) rows

5. Traffic & data-quality report

tool_run_report   (property_id, last 30 days,
  dimensions: sessionDefaultChannelGroup, sessionSource, sessionMedium,
  metrics: sessions, conversions, totalUsers)

Flag:

• A large Unassigned or (not set) share — broken UTMs or tagging gaps (point the user to /utm-builder)
• A Direct share above ~40% — usually lost referrer data or missing tags
• Self-referrals (your own domain as a source) — needs an unwanted-referral filter
• Internal traffic visible in reports — no internal-traffic filter applied

6. PII & policy check

Scan event and parameter names from get_metadata for anything that could carry personal data — email, phone, user_email, full names, raw addresses in parameters or in the page path / query string.

🔴 PII in GA4 violates Google's policy and risks the property being deleted. Flag it as critical and name the exact parameter.

7. Integrations

Flag:

• No Google Ads link — conversions can't flow to Ads for bidding (check with the user; the link isn't always API-visible)
• No BigQuery export — recommend it for any property that wants raw-data analysis (/ga4-bigquery-schema covers the schema)
• Search Console not linked

8. Score and report

GA4 Audit — [Property Name]
GA4 Health Score: X/100

Score breakdown:
  Configuration ...... X/20   (streams, retention, time zone)
  Key events ......... X/25   (the reporting + bidding anchor)
  Custom dimensions .. X/15
  Data quality ....... X/25   ((not set), Direct, self-referrals)
  Compliance ......... X/15   (PII, internal traffic)

🔴 Critical   — PII collected, no key events, retention at 2 months
🟡 Important  — unregistered dimensions, high (not set), no Ads link
🟢 Optimization — BigQuery export, enhanced measurement tuning

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

9. Record findings

{
  "title": "Email address captured in GA4 'page_location' — policy violation",
  "body": "The checkout-success URL includes ?email=… and GA4 stores it in page_location and page_path. Google policy prohibits PII in Analytics and can delete the property. Strip the parameter at the tag, or redact it before the event fires.",
  "action_type": "data_quality",
  "expected_outcome": "PII removed from collection; property compliant",
  "estimated_impact_usd": 0,
  "priority": "critical"
}

Action types: tracking_configuration, conversion_setup, data_quality, custom_dimension, integration, compliance.

Critical rules

1. PII is always critical. Flag it loudly and name the parameter.
2. Key events are the anchor — for GA4 reporting and for Ads bidding. Weight them.
3. Quote real numbers: retention months, (not set) %, dimension counts.
4. Read-only. Never change property settings — surface and recommend.