/conversion-debug

name: conversion-debug
description: Conversion Tracking Debugger — diagnose discrepancies across GTM, GA4, Google Ads & Meta Pixel with live API access, BigQuery validation queries, and troubleshooting flowcharts
version: "1.0.0"
author: Cogny AI
platforms: []
user-invocable: true
argument-hint: "<issue or topic>"
allowed-tools:
  - WebFetch
  - WebSearch
  - Bash
  - Read
  - Write
  # GTM tools
  - mcp__cogny__google_tag_manager__tool_list_tags
  - mcp__cogny__google_tag_manager__tool_list_triggers
  - mcp__cogny__google_tag_manager__tool_get_tag
  - mcp__cogny__google_tag_manager__tool_search_tags
  - mcp__cogny__google_tag_manager__tool_get_workspace_status
  # GA4 tools
  - mcp__cogny__google_analytics_4__tool_list_conversion_events
  - mcp__cogny__google_analytics_4__tool_run_report
  - mcp__cogny__google_analytics_4__tool_run_realtime_report
  - mcp__cogny__google_analytics_4__tool_list_data_streams
  # Google Ads tools
  - mcp__cogny__google_ads__tool_execute_gaql
  - mcp__cogny__google_ads__tool_get_gaql_doc
  # Meta tools
  - mcp__cogny__meta_ads__tool_get_pixels
  - mcp__cogny__meta_ads__tool_get_insights

Conversion Tracking Debugger

Debug conversion tracking across GTM, GA4, Google Ads, and Meta Pixel. Diagnose discrepancies, find duplicate conversions, validate enhanced conversions, audit Consent Mode v2, and run BigQuery validation queries.

Full docs: https://cogny.com/docs/conversion-tracking-debugger

Usage

/conversion-debug                          # Full debugging overview
/conversion-debug duplicate conversions    # Diagnose duplicate purchases
/conversion-debug consent mode             # Consent Mode v2 audit
/conversion-debug meta vs ga4              # Cross-platform discrepancy analysis
/conversion-debug enhanced conversions     # Validate enhanced conversion setup
/conversion-debug server-side tagging      # Server-side GTM overview
/conversion-debug value wrong              # Debug incorrect conversion values

Instructions

You are a conversion tracking debugging expert. Use this reference and the available MCP tools to help users diagnose and fix conversion tracking issues across GTM, GA4, Google Ads, and Meta Pixel.

When the user asks a question, find the relevant section below and provide precise, actionable answers. When MCP tools are available, use them to pull live data from the user's accounts to validate findings.

If the user provides a specific topic as an argument, focus on that area. Otherwise, ask what platform or issue they need help with.

**When MCP tools are available, follow this diagnostic approach:**

1. Use GTM tools to inspect tags, triggers, and workspace status 2. Use GA4 tools to check conversion events, run reports, and verify data streams 3. Use Google Ads tools to query conversion action status and performance 4. Use Meta tools to check pixel configuration and compare conversion counts 5. Cross-reference findings across platforms to identify the root cause

---

The Conversion Tracking Stack

Understanding data flow is the first step to debugging:

User Action (click, form submit, purchase)
        |
        v
+-------------------+
|   Website / App   |
|   (dataLayer)     |
+-------------------+
        |
        v
+-------------------+       +-------------------+
|  Google Tag       | ----> |  GA4              |
|  Manager (GTM)    |       |  (Measurement     |
|                   |       |   Protocol)       |
|  - GA4 Config Tag |       +-------------------+
|  - GA4 Event Tag  |               |
|  - Google Ads Tag |               v
|  - Meta Pixel Tag |       +-------------------+
+-------------------+       |  BigQuery Export  |
        |                   |  (daily/intraday) |
        |                   +-------------------+
        |
        +----------> +-------------------+
        |            |  Google Ads       |
        |            |  (Conversion      |
        |            |   Tracking)       |
        |            +-------------------+
        |
        +----------> +-------------------+
                     |  Meta Pixel       |
                     |  + Conversions    |
                     |    API (CAPI)     |
                     +-------------------+

**Key data flow points:**

1. **dataLayer push** -- Website pushes event data to `window.dataLayer` 2. **GTM triggers** -- Tags fire based on trigger conditions matching dataLayer events 3. **Network requests** -- Each tag sends a separate HTTP request to its destination 4. **Platform processing** -- Each platform processes, deduplicates, and attributes independently 5. **BigQuery export** -- GA4 exports raw events to BigQuery (daily ~5 AM property timezone)

Common Discrepancies and Why

GA4 vs Google Ads Conversion Count Differences

GA4 and Google Ads will almost never match. This is expected.

| Factor | GA4 | Google Ads | |--------|-----|------------| | **Attribution model** | Data-driven (cross-channel) | Data-driven (Google channels only) | | **Counting method** | Configurable: once per session or once per event | Configurable: one or every conversion | | **Conversion window** | Default 30 days | Default 30 days (up to 90 days) | | **Cross-device** | Google Signals + User-ID | Google account sign-in | | **View-through** | Not counted by default | Included for Display/Video (1-day default) | | **Data freshness** | 24-72h processing lag | Conversions appear within hours | | **Modeled conversions** | Behavioral modeling for consent gaps | Conversion modeling for unobserved |

Typical variance: 5-20% is normal. Over 20% warrants investigation.

**MCP diagnostic approach:**

1. GA4: tool_list_conversion_events → check which events are marked as conversions
2. GA4: tool_run_report → pull conversion counts by date
3. Google Ads: tool_execute_gaql → query conversion_action metrics
4. Compare the numbers and identify the gap source

Meta Pixel vs GA4 Differences

| Factor | Meta | GA4 | |--------|------|-----|