Gmail MCP

Gmail for your AI assistant — several accounts at once, on a server you own.

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gmail-mcp connects Gmail to Claude and any other MCP client. It can search and read mail, send and reply-all with quoted history, forward, handle attachments and inline images, and manage drafts, labels, and threads — across several Google accounts at the same time.

It runs as a remote server on your own Cloudflare Worker, so the same connection answers from Claude Code on a laptop, claude.ai in a browser, and Claude on a phone. Each connection signs in to one Google account, and the Google refresh token stays in your Cloudflare account.

Two things push people here. The Gmail connectors built into Claude and Google read mail and write drafts, but cannot send, and hold one Google account per assistant account. Servers that can send are usually local processes — fine at a desk, invisible from a phone.

How it compares

Deploy it

About ten minutes. You need a Cloudflare account, bun, and a Google account. A domain on the Cloudflare account is optional — without one the Worker answers on workers.dev.

1 · Create a Google OAuth client

PROJECT="gmail-mcp-$(openssl rand -hex 3)"
gcloud auth login
gcloud projects create "$PROJECT" --name="gmail-mcp"
gcloud config set project "$PROJECT"
gcloud services enable gmail.googleapis.com

Google exposes no API for the next two steps, so they happen in the Cloud console:

• OAuth consent screen → External, then under Audience press Publish app. Left in Testing, Google expires every refresh token after 7 days and each connection dies with its token. Published, the app shows an unverified-app warning at sign-in and serves up to 100 accounts.
• Credentials → Create credentials → OAuth client ID → Web application, with https://<your-host>/callback as an authorized redirect URI. Keep the client ID and secret.

<your-host> is the domain you point at the Worker, or the workers.dev hostname it gets otherwise. Deploying first and coming back to fill this in works — the guide the Worker serves at / shows the exact value.

2 · Deploy the Worker

The button copies the repository into your GitHub account, creates the KV namespace and the Durable Object, and asks for the four secrets. It deploys to workers.dev; a custom domain is attached afterwards under Settings → Domains & Routes.

From a terminal instead:

git clone https://github.com/mkpoli/gmail-mcp && cd gmail-mcp
bun install
bun run setup

bun run setup asks which domain to answer on, creates or reuses the OAUTH_KV namespace, takes the client ID and secret, generates a cookie key, and deploys. Those first two answers land in wrangler.local.jsonc, which git ignores — wrangler.jsonc names no account's namespace and no one's domain, so a clone deploys anywhere. Re-running setup to rotate a single secret is safe.

3 · Connect a client

Leave the client ID and secret fields empty — MCP clients register themselves.

claude mcp add --transport http gmail-personal https://<your-host>/mcp
claude mcp add --transport http gmail-work     https://<your-host>/mcp/work

Run /mcp in Claude Code to sign each connection in to its Google account. In claude.ai it is Settings → Connectors → Add custom connector with the same URL. Any single-segment label works after /mcp/, which is how one deployment serves several mailboxes to clients that reject two servers sharing a URL.

Your deployment serves this guide at https://<your-host>/.

What it can do

Messages leave the way a mail client sends them: plain text with an HTML alternative, file attachments, and inline images referenced by cid:, nested as multipart/mixed › multipart/related › multipart/alternative. Subjects and display names use RFC 2047, filenames use RFC 2231, so Japanese, Chinese, and emoji survive the trip.

reply_all reads the original's Reply-To, From, To, and Cc, drops your own address and any address you send mail as, answers from the one the sender wrote to, carries the References chain, and quotes the original in whichever parts you send. forward_message reproduces the forwarded envelope and can re-attach the original's files.