thunderbird-mcp-server

An MCP (Model Context Protocol) server that gives AI assistants like Claude the ability to send, read, and search emails directly — no UI automation, no browser extensions, just clean IMAP/SMTP over SSL.

Built for Claude Code, but works with any MCP-compatible client.

What it does

Instead of driving an email client's UI with clicks and keystrokes, this server exposes email operations as structured tools that an AI assistant can call programmatically:

You: "list my recent emails"
Claude Code → calls list_emails() via MCP → IMAP fetch → structured results

Related MCP server: mcp-imap

Tools

Architecture

┌─────────────┐   stdio (JSON-RPC)   ┌──────────────┐   IMAP/SMTP (SSL)   ┌─────────────┐
│ Claude Code  │ ◄──────────────────► │  server.py   │ ◄────────────────► │ Mail Server  │
│ (MCP Client) │                      │ (MCP Server) │                    │ (any IMAP)   │
└─────────────┘                       └──────────────┘                    └─────────────┘

• Transport: stdio with JSON-RPC — Claude Code launches the server as a subprocess

• Reading: IMAP4_SSL (port 993) — encrypted connection, server-side search

• Sending: SMTP_SSL (port 465) — encrypted, authenticated relay

• Auth: credentials via environment variables, never hardcoded

Setup

Prerequisites

• Python 3.9+

• An IMAP/SMTP email account

1. Clone and install

git clone https://github.com/yuvi2118/thunderbird-mcp-server.git
cd thunderbird-mcp-server
python3 -m venv venv
source venv/bin/activate
pip install "mcp[cli]>=1.0.0"

2. Configure

Copy the example env file and fill in your credentials:

cp .env.example .env
# Edit .env with your email credentials

3. Register with Claude Code

claude mcp add email -s user \
  -e EMAIL_USER=your_username \
  -e EMAIL_PASS=your_password \
  -e EMAIL_IMAP_SERVER=your.mail.server \
  -e EMAIL_SMTP_SERVER=your.mail.server \
  -e "EMAIL_FROM_NAME=Your Name" \
  -- python3 /path/to/thunderbird-mcp-server/server.py

Restart Claude Code. The email tools are now available in every session.

4. Test with MCP Inspector

npx @modelcontextprotocol/inspector -- bash run.sh

Opens a web UI at localhost:6274 where you can call each tool interactively.

Configuration

All configuration is via environment variables:

Screenshots

MCP Inspector — listing emails

MCP Inspector — sending email

Claude Code — live demo

Usage examples

Once registered, just talk naturally in Claude Code:

> list my emails
> read email 748
> search emails from "professor name"
> send an email to john@example.com about the meeting tomorrow
> show my sent folder

Tech stack

• Python — standard library only (imaplib, smtplib, email) + MCP SDK

• MCP SDK — compatible with both v1 (FastMCP) and v2 (MCPServer)

• Security — SSL/TLS for all connections, credentials via env vars following 12-factor principles

License

MIT