Better Email MCP

mcp-name: io.github.n24q02m/better-email-mcp

IMAP/SMTP email for AI agents -- read, send, organize folders, and manage attachments across multiple accounts, with auto-discovery.

Table of contents

• Features
• Install
• CLI
• Smithery
• Documentation
• Tools
• Comparison
• Remote (HTTP Mode)
• Outlook OAuth Device Code (HTTP mode)
• Configuration
• Security
• Build from Source
• Deploy to Cloudflare
• Trust Model
• License

Features

• Multi-account support -- manage 6+ email accounts (Gmail, Outlook, Yahoo, iCloud, Zoho, ProtonMail, custom IMAP)
• App Passwords -- no OAuth2 setup required for most providers; clone and run in 1 minute
• 4 composite tools with 22 actions (plus help + config__open_relay) -- search, read, send, reply, forward, organize, and credential setup in single calls
• Auto-discovery -- provider settings detected from email address, custom IMAP host supported
• Thread-aware -- reply/forward maintains In-Reply-To and References headers
• Tiered token optimization -- compressed descriptions + on-demand help tool + MCP Resources

Install

The server runs in two modes: stdio (default, single-user, credentials from env vars) and HTTP (opt-in, multi-user with OAuth 2.1). For stdio, add it to your MCP client config:

{
  "mcpServers": {
    "better-email": {
      "command": "npx",
      "args": ["--yes", "@n24q02m/better-email-mcp@latest"],
      "env": {
        "EMAIL_CREDENTIALS": "user@gmail.com:app-password"
      }
    }
  }
}

Multiple accounts are comma-separated: user1@gmail.com:pass1,user2@outlook.com:pass2. See Configuration for all env vars, and Remote (HTTP Mode) to run a hosted multi-user server.

Most providers use an App Password (no OAuth setup); Outlook/Hotmail/Live use a bundled OAuth device-code flow in HTTP mode. Settings (IMAP/SMTP host, port) are auto-discovered from the email domain.

CLI

The package ships one binary, better-email-mcp (run via npx @n24q02m/better-email-mcp). With no arguments it starts the MCP server over stdio; it also accepts one flag and one subcommand:

# stdio server (normally launched by your MCP client, not by hand)
EMAIL_CREDENTIALS="user@gmail.com:app-password" npx @n24q02m/better-email-mcp

# HTTP multi-user server
npx @n24q02m/better-email-mcp --http

# One-off Outlook OAuth device-code sign-in
npx @n24q02m/better-email-mcp auth user@outlook.com

# Sign out of a single account (or omit the email to clear all)
npx @n24q02m/better-email-mcp logout user@outlook.com

auth/logout are only for Outlook/Hotmail/Live addresses -- other providers use an App Password in EMAIL_CREDENTIALS. See Remote (HTTP Mode) for the HTTP config.

Smithery

Published with a Smithery config (smithery.yaml). Smithery runs the server over stdio with no build config required; credentials are supplied at runtime through the server's own setup flow (see Configuration). The start command is:

startCommand:
  type: stdio
  commandFunction: |-
    (config) => ({ command: 'npx', args: ['-y', '@n24q02m/better-email-mcp'] })

Documentation

Full docs at mcp.n24q02m.com/servers/better-email-mcp/setup/:

• Setup -- install methods for Claude Code, Codex, Gemini CLI, Cursor, Windsurf, mcp.json
• Modes overview -- stdio (default) and HTTP (opt-in, multi-user with OAuth 2.1)
• Multi-user setup -- per-JWT-sub credential model

Install with AI agent -- paste this to your AI coding agent:

Install MCP server better-email-mcp following the steps at https://raw.githubusercontent.com/n24q02m/claude-plugins/main/plugins/better-email-mcp/setup-with-agent.md

Tools

Public tool rename

The public send tool is replaced by messages with action: new, reply, or forward. This follows the MCP N+2 standard: sending is an action in the messages domain, so keeping a separate send entry would duplicate that domain and add redundant tool-list and help-topic surface. The old name is removed directly; there is no compatibility alias.

MCP Resources

Comparison

How better-email-mcp stacks up against direct competitors in each pillar:

Remote (HTTP Mode)

Run as a multi-user HTTP server with OAuth 2.1 authentication:

{
  "mcpServers": {
    "better-email": {
      "type": "http",
      "url": "https://<your-host>/mcp"
    }
  }
}

Self-Hosting (HTTP Mode)

Single multi-user mode (relay form for App-Password providers + bundled Outlook OAuth device-code):

export CREDENTIAL_SECRET='replace-with-a-stable-secret'
docker run -p 8080:8080 \
  -e PORT=8080 \
  -e PUBLIC_URL=https://your-domain.com \
  -e MCP_STORAGE_BACKEND=local \
  -e HOME=/data \
  -e CREDENTIAL_SECRET="$CREDENTIAL_SECRET" \
  -v email-data:/data \
  n24q02m/better-email-mcp:latest

Users provide their own email credentials through the OAuth flow / paste form. No server-side EMAIL_CREDENTIALS is needed. The stable CREDENTIAL_SECRET encrypts the local per-user credential files; the mounted /data volume survives container restarts. Without that volume, the container filesystem remains ephemeral. Cloudflare deployments use Workers KV instead.

Cloudflare serverless mode (KV-only)

Self-hostable as a per-user serverless instance on Cloudflare Workers + Containers: each JWT sub gets its own Container Durable Object, and all credentials AND Outlook OAuth tokens are AES-256-GCM encrypted into Workers KV (one subs/<sub>/config blob per user) so they survive scale-to-zero / container recreate with no re-auth. The JWT signing key is derived deterministically from CREDENTIAL_SECRET (EdDSA), so the user's identity is stable across recreate. Required secrets: CREDENTIAL_SECRET (per-sub vault + EdDSA), MCP_RELAY_PASSWORD (form gate), MCP_DCR_SERVER_SECRET (intentional multi-user deploy). See wrangler.jsonc.

Keying Outlook tokens by JWT sub (in the per-sub KV blob) resolves the former email-keyed tokens.json ambiguity (CLAUDE.md Known Bug #4): two users' Outlook accounts can no longer collide.

Caveat: localhost IMAP accounts (email:pass:localhost:1993) are valid for local / VM deployments but CANNOT work on Cloudflare — there is no co-located IMAP proxy inside the container. Use a publicly-reachable IMAP host on CF.

Outlook OAuth Device Code (HTTP mode)

In HTTP mode, Outlook/Hotmail/Live accounts use OAuth2 device-code automatically. On first use:

1. The server prints a device code and a Microsoft login URL
2. Open the URL in a browser and enter the code
3. Sign in and authorize the app
4. Tokens are persisted per JWT sub — in the encrypted Cloudflare KV credential blob (subs/<sub>/config) on the serverless deploy, in the local in-memory store for local HTTP, or in ~/.better-email-mcp/tokens.json for single-user / stdio

OAuth uses the bundled public Azure client (d56f8c71-9f7c-43f4-9934-be29cb6e77b0, Thunderbird-pattern) -- no user-side Azure registration needed.

In stdio mode, Outlook accounts use an App Password instead (Outlook Account Settings → Security → Advanced security options → App passwords).

Configuration

To trust mise configuration automatically, set trusted_config_paths in the user-level config at ~/.config/mise/config.toml; do not add it to this project's .mise.toml.

Multiple Accounts

EMAIL_CREDENTIALS=user1@gmail.com:pass1,user2@outlook.com:pass2,user3@yahoo.com:pass3

Custom IMAP Host

# Custom hostname (default port 993, implicit TLS)
EMAIL_CREDENTIALS=user@custom.com:password:imap.custom.com

# Custom hostname with a custom port
EMAIL_CREDENTIALS=user@custom.com:password:imap.custom.com:1993

# Local IMAP proxy -- "localhost" is accepted as a host, even without a dot
EMAIL_CREDENTIALS=user@custom.com:password:localhost:1993

Each account can use its own host and port. A non-993 port is treated as plaintext/STARTTLS -- the usual shape for a local IMAP proxy (for example email-oauth2-proxy).

Microsoft 365 work/school accounts

A mailbox in a Microsoft 365 organisation -- including one on your own domain -- signs in through Entra ID rather than the consumer directory, and Microsoft disabled basic auth for Exchange Online in 2024, so an App Password is not an option. Two settings make it work:

# Sign in against the directory that owns the mailbox
OUTLOOK_TENANT=common                      # or a tenant GUID / verified domain

# Route your own domain to OAuth instead of asking for a password
OUTLOOK_EXTRA_DOMAINS=company.com

OUTLOOK_TENANT applies to the token refresh as well as the initial sign-in -- refreshing a work/school token against the consumer directory fails with AADSTS7000012: The grant was obtained for a different tenant.

If the mailbox was consented with a narrower grant (say IMAP but no SMTP), match it with OUTLOOK_SCOPES so the refresh does not ask for more than was granted.

Search Query Language

Supported Providers

Security

• Credential sanitization -- Passwords never leaked in error messages
• App Passwords -- Uses app-specific passwords, not regular passwords
• Token storage -- Outlook OAuth tokens saved with 600 permissions
• IMAP validation -- Search queries validated before execution

Build from Source

git clone https://github.com/n24q02m/better-email-mcp.git
cd better-email-mcp
bun install
bun run dev

Deploy to Cloudflare

Run your own multi-user better-email instance serverless on Cloudflare (Containers + KV). Each JWT sub gets its own Container Durable Object, and every user's email credentials and Outlook OAuth tokens are AES-256-GCM encrypted into a single Workers KV blob per user, so they survive scale-to-zero / container recreate with no re-auth.

Prerequisites: a Cloudflare account on the Workers Paid plan — required for Containers (the Cloudflare free tier does not include Containers) — and the wrangler CLI.

1. git clone https://github.com/n24q02m/better-email-mcp && cd better-email-mcp
2. wrangler login
3. Create the KV namespace (better-email is KV-only -- no D1 / Vectorize):
   Terminal

   Copy

   wrangler kv namespace create better-email-kv
   

   Paste the returned id into <better-email-kv-namespace-id> in wrangler.jsonc.
4. Push the container image to your Cloudflare managed registry (CF Containers cannot pull from external registries directly), then set <YOUR_ACCOUNT_ID> in wrangler.jsonc:
   Terminal

   Copy

   docker pull ghcr.io/n24q02m/better-email-mcp:beta
   docker tag ghcr.io/n24q02m/better-email-mcp:beta better-email-mcp:beta
   wrangler containers push better-email-mcp:beta   # prints registry.cloudflare.com/<ACCOUNT_ID>/better-email-mcp:beta
   

5. Point wrangler.jsonc at your own domain: set <YOUR_PUBLIC_URL> (e.g. https://email.example.com) and <YOUR_WORKER_DOMAIN> (e.g. email.example.com).
6. Set the deploy secrets:
   Terminal

   Copy

   wrangler secret put CREDENTIAL_SECRET      # per-sub vault key + deterministic EdDSA signing (required)
   wrangler secret put MCP_RELAY_PASSWORD     # gate for the /authorize setup form
   wrangler secret put MCP_DCR_SERVER_SECRET  # proof of an intentional multi-user deploy
   

   Optional Outlook overrides -- only to replace the bundled public Azure device-code client (default needs no user-side Azure app): wrangler secret put OUTLOOK_CLIENT_ID and wrangler secret put OUTLOOK_EMAIL. For a Microsoft 365 organisation, also set OUTLOOK_TENANT (and OUTLOOK_EXTRA_DOMAINS for mailboxes on your own domain).
7. wrangler deploy, then open <YOUR_PUBLIC_URL>/authorize and complete the browser relay form.

End-users supply their own email credentials -- an App Password via the paste form, or the bundled Outlook device-code sign-in -- through that relay form; there is no server-side EMAIL_CREDENTIALS. Storage maps to Cloudflare via MCP_STORAGE_BACKEND=cf-kv (already set in wrangler.jsonc); see Cloudflare serverless mode (KV-only) for the encryption and trust details.

Trust Model

This plugin implements TC-NearZK. Storage durability depends on the deployment mode; see the mcp-core trust model for full classification.

License

Apache-2.0 -- See LICENSE.