GTM MCP Server

A Model Context Protocol (MCP) server for Google Tag Manager using service account authentication - no OAuth dance required.

Features

• No OAuth required - Uses Google Service Account for authentication
• Covers the core GTM workflow - Accounts, Containers, Workspaces, Tags, Triggers, Variables, Built-In Variables, and Versions (29 tools)
• Local & private - Runs entirely on your machine
• Works with Claude Desktop, Cursor, and other MCP clients

Quick Start

1. Create a Google Cloud Service Account

1. Go to Google Cloud Console
2. Select or create a project
3. Enable the Tag Manager API:
   • Go to APIs & Services → Library
   • Search for "Tag Manager API"
   • Click Enable
4. Create a service account:
   • Go to IAM & Admin → Service Accounts
   • Click "Create Service Account"
   • Give it a name (e.g., "gtm-mcp-server")
   • Click Create and Continue (skip optional permissions)
   • Click Done
5. Create a key:
   • Click on your new service account
   • Go to Keys tab
   • Add Key → Create new key → JSON
   • Save the downloaded JSON file somewhere safe (e.g., ~/.config/gtm-service-account.json)

2. Grant GTM Access to the Service Account

1. Go to Google Tag Manager
2. Click Admin (gear icon)
3. Under Account, click "User Management"
4. Click the + button to add a user
5. Enter the service account email (looks like name@project-id.iam.gserviceaccount.com)
6. Set appropriate permissions:
   • Read - for listing/viewing only
   • Edit - for creating/modifying tags, triggers, variables
   • Publish - for publishing versions
   • Admin - for full access including user management

3. Configure Your MCP Client

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on Mac, %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "gtm": {
      "command": "npx",
      "args": ["-y", "gtm-mcp-server"],
      "env": {
        "GOOGLE_APPLICATION_CREDENTIALS": "/path/to/your/service-account.json"
      }
    }
  }
}

Cursor

Add to your Cursor MCP settings:

{
  "mcpServers": {
    "gtm": {
      "command": "npx",
      "args": ["-y", "gtm-mcp-server"],
      "env": {
        "GOOGLE_APPLICATION_CREDENTIALS": "/path/to/your/service-account.json"
      }
    }
  }
}

4. Restart Your Client

After saving the config, restart your MCP client. You should see the GTM tools available.

Available Tools

Account Management

• gtm_list_accounts - List all accessible GTM accounts

Container Management

• gtm_list_containers - List containers in an account
• gtm_get_container - Get container details

Workspace Management

• gtm_list_workspaces - List workspaces in a container
• gtm_create_workspace - Create a new workspace
• gtm_get_workspace_status - Show pending changes and merge conflicts in a workspace
• gtm_sync_workspace - Sync a workspace to the latest container version

Tag Management

• gtm_list_tags - List all tags in a workspace
• gtm_get_tag - Get full tag details with parameters
• gtm_create_tag - Create a new tag
• gtm_update_tag - Update an existing tag
• gtm_delete_tag - Delete a tag

Trigger Management

• gtm_list_triggers - List all triggers in a workspace
• gtm_get_trigger - Get full trigger details
• gtm_create_trigger - Create a new trigger
• gtm_update_trigger - Update an existing trigger
• gtm_delete_trigger - Delete a trigger

Variable Management

• gtm_list_variables - List all variables in a workspace
• gtm_get_variable - Get full variable details
• gtm_create_variable - Create a new variable
• gtm_update_variable - Update an existing variable
• gtm_delete_variable - Delete a variable

Built-In Variable Management

• gtm_list_built_in_variables - List enabled built-in variables
• gtm_enable_built_in_variables - Enable built-in variables (e.g. Page URL, Click Classes)
• gtm_disable_built_in_variables - Disable built-in variables

Version Management

• gtm_list_versions - List container versions
• gtm_get_live_version - Get the currently live (published) version
• gtm_create_version - Create a version from a workspace
• gtm_publish_version - Publish a version to make it live

All list tools return results one page at a time; when more results exist, the response includes a page_token to pass to the next call.

Usage Examples

Once configured, you can ask Claude things like:

• "List my GTM accounts"
• "Show me all containers in account 123456"
• "What tags are in my website container?"
• "Create a new pageview trigger called 'All Pages'"
• "Create a custom HTML tag that fires on all pages"
• "Create a version and publish it"

Troubleshooting

"GOOGLE_APPLICATION_CREDENTIALS not set"

Make sure the environment variable is set in your MCP client config and points to a valid JSON key file.

"Permission denied" errors

• Verify the service account email has been added to your GTM account
• Check that the permission level is sufficient for the operation

"API not enabled" errors

Make sure the Tag Manager API is enabled in your Google Cloud project.

Server not appearing in Claude Desktop

• Check that the paths in your config are correct
• Look at Claude Desktop's MCP logs for errors
• Try running npx gtm-mcp-server directly to see any error messages

Development

# Clone the repository
git clone https://github.com/alexstansfield/gtm-mcp-server.git
cd gtm-mcp-server

# Install dependencies
npm install

# Build
npm run build

# Watch mode for development
npm run dev

# Test with MCP Inspector
npx @modelcontextprotocol/inspector node dist/index.js

License

MIT