Google Analytics MCP server on Cloudflare Workers

A Model Context Protocol server that gives MCP clients (Claude, Gemini CLI, etc.) read access to Google Analytics 4 data, running as a Cloudflare Worker instead of the local pipx run analytics-mcp process from the original googleanalytics/google-analytics-mcp project.

Because a Worker can't run gcloud/Application Default Credentials the way a local process can, this port authenticates with a GCP service account key stored as a Cloudflare secret: the Worker signs its own JWT (via the Workers Web Crypto API) and exchanges it for a Google OAuth2 access token on each cold start.

The button above clones this repo into your own GitHub account, provisions a new Worker on your Cloudflare account, and wires up auto-deploy on every push. It does not set the GA_SERVICE_ACCOUNT_KEY / MCP_LOGIN_PASSWORD secrets or create the OAUTH_KV namespace for you — you still need to complete the Google Cloud setup below and steps 3 (KV namespace) and 4 (secrets) before the server can actually reach Google Analytics or let anyone sign in.

Tools exposed

Same 9 tools as the original server, called via the GA4 Data API and Admin API REST endpoints directly:

date_ranges, dimension_filter, metric_filter, and order_bys use the Data API's own camelCase REST JSON shapes directly (e.g. {"fieldName":"country","stringFilter":{"value":"United States"}}) rather than the snake_case Python proto kwargs the original server used — see the FilterExpression reference.

Related MCP server: google-ads-mcp-worker

1. Google Cloud setup

You'll need a GCP project with the Analytics Admin API and Analytics Data API enabled, and a service account granted read access to your GA4 properties. None of this can be done on your behalf from here — a Google Cloud project and Google Analytics account access are tied to your Google identity.

1. Create (or pick) a GCP project.

   gcloud projects create wigwam-ga-mcp --name="Wigwam GA MCP"
   gcloud config set project wigwam-ga-mcp

2. Enable the required APIs.

   gcloud services enable analyticsadmin.googleapis.com analyticsdata.googleapis.com

3. Create a service account and a JSON key for it.

   gcloud iam service-accounts create ga-mcp-reader \
     --display-name="GA4 MCP read-only"
   
   gcloud iam service-accounts keys create ga-mcp-key.json \
     --iam-account=ga-mcp-reader@wigwam-ga-mcp.iam.gserviceaccount.com

   ga-mcp-key.json is a secret — don't commit it. You'll paste its contents into a Cloudflare secret in step 3 below, then delete the local file.

4. Grant the service account access to your GA4 properties. This step happens in the Google Analytics UI, not GCP, since GA4 property access isn't an IAM role:

   • Go to analytics.google.com → Admin → Property Access Management (or Account Access Management to grant it across every property in the account at once).

   • Click + → Add users.

   • Enter the service account's email (ga-mcp-reader@wigwam-ga-mcp.iam.gserviceaccount.com).

   • Assign the Viewer role. Uncheck "Notify new users by email" (service accounts can't read email).

2. How auth works: a real OAuth 2.1 login, one shared password

Clients like claude.ai's and Claude Desktop's "Add custom connector" flow expect a remote MCP server to speak OAuth 2.1 (dynamic client registration, an authorization redirect, a token exchange) — they don't support pasting in a static bearer token. So this server implements that flow using @cloudflare/workers-oauth-provider:

• /register, /token — handled entirely by the library (dynamic client registration + code-for-token exchange), no code needed.

• /authorize — a login page this repo implements (src/oauth-handler.ts): it asks for one password (MCP_LOGIN_PASSWORD), and on success calls completeAuthorization() to issue the client a token.

• There's only one login for everyone (no per-user accounts) since every caller ends up using the same GA service account regardless of who signed in — the password just gates who's allowed to add the connector at all.

• OAuthProvider stores registered clients and issued grants/tokens in a Workers KV namespace (OAUTH_KV), created in step 3 below.

3. Create the KV namespace

npx wrangler kv namespace create OAUTH_KV

This prints an id. Paste it into wrangler.jsonc's kv_namespaces entry, replacing the placeholder string.

4. Local development

npm install
cp .dev.vars.example .dev.vars
# edit .dev.vars: paste the service account JSON as GA_SERVICE_ACCOUNT_KEY,
# and set MCP_LOGIN_PASSWORD to whatever password you want to sign in with
npm run dev

wrangler dev will print a local URL; MCP clients can connect to http://localhost:8787/mcp and will be sent through the /authorize login page on first connection.

5. Deploy to Cloudflare

npx wrangler login          # first time only
npx wrangler secret put GA_SERVICE_ACCOUNT_KEY   # paste the full JSON key contents
npx wrangler secret put MCP_LOGIN_PASSWORD        # the password you'll type in at /authorize
npm run deploy

Wrangler will print the deployed URL, e.g. https://wigwam-google-analytics-mcp.<your-subdomain>.workers.dev.

6. Connect an MCP client

Point your client at the /mcp URL, e.g. https://wigwam-google-analytics-mcp.<your-subdomain>.workers.dev/mcp. Since this is now a real OAuth flow, clients that support remote connectors (the claude.ai and Claude Desktop "Add custom connector" UI, for example) can add it directly from just that URL — no manual header configuration needed. The first connection will redirect to the /authorize login page; enter the MCP_LOGIN_PASSWORD you set above.

For clients that use a config file with a raw url field instead of a UI (some Claude Desktop versions, Claude Code's .mcp.json), the same URL works the same way — the client handles the OAuth redirect/token exchange itself:

{
  "mcpServers": {
    "google-analytics": {
      "url": "https://wigwam-google-analytics-mcp.<your-subdomain>.workers.dev/mcp"
    }
  }
}

An SSE-transport endpoint is also available at /sse for clients that don't yet support Streamable HTTP.

Project layout

src/
  index.ts          MCP server definition (tool schemas) + OAuthProvider wiring
  oauth-handler.ts  The /authorize login page and completeAuthorization() call
  ga-client.ts      fetch() wrappers for the GA Admin API and Data API
  auth.ts           Service-account JWT signing + Google OAuth2 token exchange
wrangler.jsonc      Worker/Durable Object/KV configuration