pyfastmail-mcp

An MCP server that gives AI assistants full access to your Fastmail account — email, contacts, calendars, and file storage.

> ⚠️ This server can send email, delete messages, and modify contacts/calendars on your behalf. AI assistants may act on content from untrusted sources (emails, web pages, files) which could contain prompt injection attacks. Review tool calls before approving them, especially actions that send email or delete data.

Features

Installation

pip install pyfastmail-mcp

Or run directly with `uvx`:

uvx pyfastmail-mcp

Configuration

1. Get Fastmail Credentials

You need an API token from Fastmail. An app password is optional (only needed for calendar and file storage).

• API Token (required — mail and contacts): Fastmail Settings → Privacy & Security → API Tokens — enable the `urn:ietf:params:jmap:contacts` capability
• App Password (optional — calendars and files): Fastmail Settings → Privacy & Security → App Passwords — create one with the "DAV (CardDAV, CalDAV, WebDAV)" scope

If you only set the API token, the server starts with mail and contacts tools. Calendar and file tools are registered only when the app password is also provided.

2. Set Environment Variables

export FASTMAIL_API_TOKEN="fmu1-..."
export FASTMAIL_APP_PASSWORD="your-app-password"
export FASTMAIL_EMAIL="you@fastmail.com"

3. Add to Your MCP Client

For Claude Desktop, add to `claude_desktop_config.json`:

{
  "mcpServers": {
    "fastmail": {
      "command": "uvx",
      "args": ["pyfastmail-mcp"],
      "env": {
        "FASTMAIL_API_TOKEN": "fmu1-...",
        "FASTMAIL_APP_PASSWORD": "your-app-password",
        "FASTMAIL_EMAIL": "you@fastmail.com"
      }
    }
  }
}

For Kiro CLI, add to `.kiro/settings/mcp.json`:

{
  "mcpServers": {
    "fastmail": {
      "command": "uvx",
      "args": ["pyfastmail-mcp"],
      "env": {
        "FASTMAIL_API_TOKEN": "${FASTMAIL_API_TOKEN}",
        "FASTMAIL_EMAIL": "${FASTMAIL_EMAIL}",
        "FASTMAIL_APP_PASSWORD": "${FASTMAIL_APP_PASSWORD}"
      }
    }
  }
}

Tools

Mail (`mail_*`)

Contacts (`contacts_*`)

Calendar (`calendar_*`)

Files (`files_*`)

Development

git clone https://github.com/pjosols/pyfastmail-mcp.git
cd pyfastmail-mcp
uv sync --group dev
uv run pytest

License

MIT