paolobtl/gtm-mcp

GTM MCP Server

A Model Context Protocol (MCP) server that enables Claude to interact with Google Tag Manager.

Table of Contents

• Features
• Quick Start
  • Prerequisites
• Complete Setup Guide
  • Part 1: Install the Package
  • Alternative Install Options
    • Install in development mode (editable)
    • Install from built wheel
    • Install from source tarball
  • Part 2: Create Google Cloud OAuth Credentials
    • Step 1: Create a Google Cloud Project
    • Step 2: Enable Tag Manager API
    • Step 3: Configure OAuth Consent Screen
    • Step 4: Create OAuth Credentials
    • Step 5: Save Your Credentials
  • Part 3: Configure Claude Desktop
  • Part 4: Restart and Authorize
• Available Tools
• How Authentication Works
• Upgrade
• Troubleshooting
• Security Notes
• Development
  • Running Tests
• License
• Contributing
• Getting Help

Features

⬆ top

• List GTM accounts and containers
• Manage tags, triggers, and variables
• Create and publish container versions
• Full workspace management

🚀 Quick Start

⬆ top

Prerequisites

• Python 3.10 or higher
• Claude Desktop (or any MCP-compatible client like Cursor)
• A Google account with access to Google Tag Manager

📋 Complete Setup Guide

⬆ top

Part 1: Install the Package

pip install gtm-mcp

See PyPi

🔧 Alternative Install Options

Instead of installing from PyPI, you can also install from source or from the built distributions:

1. Install in development mode (editable)

git clone https://github.com/paolobtl/gtm-mcp.git
cd gtm-mcp
pip install -e .

Useful if you plan to modify the code locally. Changes in src/gtm_mcp/ are immediately reflected.

Run this command from the same directory where pyproject.toml is located:

This command should output a lot of text and once completed should generate two files in the dist directory.

2. Install from built wheel

pip install dist/gtm_mcp-0.1.0-py3-none-any.whl

3. Install from source tarball

pip install dist/gtm_mcp-0.1.0.tar.gz

Part 2: Create Google Cloud OAuth Credentials

⬆ top

Step 1: Create a Google Cloud Project

1. Go to Google Cloud Console
2. Click on the project dropdown (top left)
3. Click "New Project"
4. Enter a project name (e.g., "My GTM MCP Server")
5. Click "Create"
6. Wait for the project to be created and select it

Step 2: Enable Tag Manager API

1. In your project, go to "APIs & Services" → "Library"
2. Search for "Tag Manager API"
3. Click on it and click "Enable"
4. Wait for it to enable (may take a minute)

Step 3: Configure OAuth Consent Screen

1. Go to "APIs & Services" → "OAuth consent screen"
2. Select "External" (unless you have a Google Workspace)
3. Click "Create"
4. Fill in required fields:
   • App name: My GTM MCP (or whatever you like)
   • User support email: Your email
   • Developer contact email: Your email
5. Click "Save and Continue"
6. Click "Update" then "Save and Continue"
7. Add your email as a test user
8. Click "Save and Continue"

Step 4: Create OAuth Credentials

1. Go to "APIs & Services" → "Credentials"
2. Click "Create Credentials" → "OAuth client ID"
3. Select "Desktop app" as the application type
4. Enter a name: "GTM MCP Desktop Client"
5. Click "Create"
6. IMPORTANT: A dialog appears with your credentials - DO NOT CLOSE IT YET

Step 5: Save Your Credentials

From the dialog that appeared:

1. Copy the Client ID (looks like: 123456789-abc123.apps.googleusercontent.com)
2. Copy the Client secret (looks like: GOCSPX-...)
3. Note your Project ID from the Google Cloud Console (top bar, next to project name)
4. Save these somewhere safe - you'll need them in the next step

You can also download the JSON file, but you only need the three values above.

Part 3: Configure Claude Desktop

⬆ top Edit your Claude Desktop config file:

• Linux: ~/.config/Claude/claude_desktop_config.json
• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Claude Code ~/.claude.json

Add your credentials:

{
  "mcpServers": {
    "gtm-mcp": {
      "command": "gtm-mcp",
      "env": {
        "GTM_CLIENT_ID": "your-client-id.apps.googleusercontent.com",
        "GTM_CLIENT_SECRET": "GOCSPX-your-client-secret",
        "GTM_PROJECT_ID": "your-project-id"
      }
    }
  }
}

Replace the values with your actual credentials from Part 2, Step 5.

Note: If you have other MCP servers configured, just add the "gtm-mcp" entry to the existing "mcpServers" object.

Part 4: Restart and Authorize

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1. Restart Claude Desktop completely (close and reopen)

2. Ask Claude to use a GTM tool (e.g., "List my GTM accounts")

3. First-time authorization - a browser window will open automatically:

   • Sign in with your Google account
   • You'll see "Google hasn't verified this app" warning
   • Click "Advanced" → "Go to [Your App Name] (unsafe)"
   • This is safe because you created the app yourself
   • Grant the requested permissions
   • You'll see "The authentication flow has completed"
   • Return to Claude Desktop

4. Your authorization is saved locally - you won't need to do this again!

🛠️ Available Tools

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Once configured, Claude will have access to these GTM tools:

🔐 How Authentication Works

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This MCP server uses OAuth 2.0 to securely access Google Tag Manager:

1. You create OAuth credentials in your own Google Cloud project
2. You configure those credentials in Claude Desktop
3. First use: Browser opens to authorize access to your GTM account
4. Your tokens are saved locally on your machine (~/.gtm-mcp-token.json) for future use

Why Do I Need My Own OAuth Credentials?

For security and privacy:

• ✅ You maintain full control over the OAuth app
• ✅ No shared credentials between users
• ✅ You can revoke access anytime
• ✅ Your credentials stay private
• ✅ Compliant with Google's OAuth policies

Upgrade

Run pip install --upgrade gtm-mcp

❓ Troubleshooting

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"Missing required OAuth credentials" Error

Problem: The MCP server can't find your credentials.

Solution: Make sure you:

• Set the environment variables correctly in claude_desktop_config.json (or ~/.claude.json)
• Restarted Claude Desktop after editing the config
• Used the correct format (no extra quotes in JSON)
• The config file is valid JSON (use a JSON validator if unsure)

"Google hasn't verified this app" Warning

Problem: Google shows a security warning during first authorization.

Solution: This is completely normal for personal OAuth apps. Since you created the OAuth app yourself, Google shows this warning.

To proceed: Click "Advanced" → "Go to [App Name] (unsafe)"

This is safe because you control the app.

Can't Access GTM Accounts

Possible causes:

• Your Google account doesn't have access to any GTM accounts
• You didn't grant all requested permissions during authorization
• Tag Manager API isn't enabled in your Google Cloud project

Solution:

1. Verify your Google account has GTM access
2. Re-authorize by deleting ~/.gtm-mcp-token.json and trying again
3. Check that Tag Manager API is enabled in Google Cloud Console

Connection Issues

Debugging steps:

1. Verify Claude Desktop is completely restarted
2. Check Claude Desktop logs for MCP server errors
3. Verify gtm-mcp command works: run gtm-mcp in terminal
4. Check your config file is valid JSON
5. Ensure all three environment variables are set correctly

Package Not Found After Install

Problem: gtm-mcp command not found after installation.

Solution:

# Ensure pip install location is in PATH
pip install --user gtm-mcp

# Or use pipx for isolated installation
pipx install gtm-mcp

Revoking Access

To revoke access to your GTM account:

1. Go to Google Account Permissions
2. Find your app name in the list
3. Click "Remove access"
4. Delete the local token file: rm ~/.gtm-mcp-token.json

You can re-authorize anytime by using any GTM tool in Claude again.

🔒 Security Notes

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• Your OAuth credentials are yours alone - keep them private
• Never share your Client Secret - treat it like a password
• Your access tokens are stored locally: ~/.gtm-mcp-token.json
• You can regenerate credentials anytime in Google Cloud Console
• You can revoke access anytime from your Google account settings
• This server only accesses GTM - no other Google services

💻 Development

Running Tests

pip install -e ".[dev]"
pytest

📝 License

⬆ top see LICENSE file for details

🤝 Contributing

⬆ top Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

For bugs and feature requests, please open an issue.

🆘 Getting Help

⬆ top If you encounter issues:

1. Check the Troubleshooting section above
2. Review Claude Desktop logs for error messages
3. Verify your Google Cloud project has Tag Manager API enabled
4. Ensure environment variables are set correctly in the config
5. Open an issue on GitHub with:
   • Your operating system
   • Python version (python --version)
   • Error messages from Claude Desktop logs
   • Steps to reproduce the issue