MCP Server for Google Tag Manager

This is a server that supports remote MCP connections, with Google OAuth built-in and provides an interface to the Google Tag Manager API.

Access the remote MCP server from Claude Desktop

Open Claude Desktop and navigate to Settings -> Developer -> Edit Config. This opens the configuration file that controls which MCP servers Claude can access.

Replace the content with the following configuration. Once you restart Claude Desktop, a browser window will open showing your OAuth login page. Complete the authentication flow to grant Claude access to your MCP server. After you grant access, the tools will become available for you to use.

{
  "mcpServers": {
    "gtm-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://gtm-mcp.stape.ai/mcp"
      ]
    }
  }
}

Troubleshooting

MCP Server Name Length Limit

Some MCP clients (like Cursor AI) have a 60-character limit for the combined MCP server name + tool name length. If you use a longer server name in your configuration (e.g., gtm-mcp-server-your-additional-long-name), some tools may be filtered out.

To avoid this issue:

• Use shorter server names in your MCP configuration (e.g., gtm-mcp-server)

Clearing MCP Cache

mcp-remote stores all the credential information inside ~/.mcp-auth (or wherever your MCP_REMOTE_CONFIG_DIR points to). If you're having persistent issues, try running:

rm -rf ~/.mcp-auth

Then, restart your MCP client.

Running locally for development/testing

You can run the server on your own machine against your own Google Cloud OAuth credentials instead of the hosted gtm-mcp.stape.ai server. This is useful for testing changes before they're deployed.

1. Set up a Google Cloud OAuth client

1. In the Google Cloud Console, create or select a project, then enable the Tag Manager API.
2. Go to APIs & Services > OAuth consent screen and configure it (External is fine). While the app is in Testing publishing status, only accounts listed as test users can log in.
3. Go to Audience, under Test users add your own Google account.
4. Go to APIs & Services > Credentials > Create Credentials > OAuth client ID, type Web application.
5. Under Authorized redirect URIs, add http://localhost:8788/callback. (You can leave Authorized JavaScript origins empty — this flow is server-side only, no browser JS calls Google directly.)
6. Save, then copy the generated Client ID and Client secret.

2. Configure local environment variables

Copy the example file and fill in the values from the previous step:

cp .dev.vars.example .dev.vars

GOOGLE_CLIENT_ID="<your client ID>"
GOOGLE_CLIENT_SECRET="<your client secret>"
COOKIE_ENCRYPTION_KEY="<any random string, at least 32 chars, e.g. output of: openssl rand -hex 32>"
WORKER_HOST="http://localhost:8788"
HOSTED_DOMAIN=""

.dev.vars is git-ignored — it's only used locally and never committed.

3. Start the server

npm install
npm run dev

This starts the Worker on http://localhost:8788.

4. Point your MCP client at the local server

Same as the Claude Desktop config above, but pointing at localhost instead of the hosted URL:

{
  "mcpServers": {
    "gtm-mcp-server-local": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "http://localhost:8788/mcp"]
    }
  }
}

Restart Claude Desktop. A browser window will open for the Google OAuth flow; log in with the account you added as a test user in step 1.

Note: if you've previously connected to the hosted server (or switch back and forth between local and hosted), clear mcp-remote's cache first (see "Clearing MCP Cache" above) and fully restart your MCP client, otherwise it may reuse a stale/cached connection.