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

42 tools across 4 protocols:

Domain	Protocol	Tools
Mail	JMAP	Send, reply, forward, search, read, archive, labels, masked email, attachments, threads
Contacts	CardDAV	List address books, CRUD contacts
Calendar	CalDAV	List calendars, CRUD events
Files	WebDAV	List, upload, download, move, delete, create folders

Installation

pip install pyfastmail-mcp

Or run directly with uvx:

uvx pyfastmail-mcp

Configuration

1. Get Fastmail Credentials

You need two credentials from Fastmail:

• API Token (for JMAP/mail): Fastmail Settings → Privacy & Security → API Tokens
• App Password (for CardDAV/CalDAV/WebDAV): Fastmail Settings → Privacy & Security → App Passwords — create one with DAV access

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_*)

Tool	Description
health_check	Verify connection and auth
mail_list_mailboxes	List all mailboxes
mail_create_mailbox	Create a mailbox
mail_rename_mailbox	Rename a mailbox
mail_delete_mailbox	Delete a mailbox
mail_get_email	Get a single email by ID
mail_get_recent_emails	Get recent emails
mail_search_emails	Search by query
mail_get_email_thread	Get full thread
mail_mark_email_read	Mark read/unread
mail_move_email	Move to mailbox
mail_delete_email	Move to trash
mail_archive_email	Archive
mail_manage_email_labels	Add/remove labels
mail_list_identities	List send-as identities
mail_send_email	Send new email
mail_reply_to_email	Reply to email
mail_forward_email	Forward email
mail_list_masked_emails	List masked emails
mail_create_masked_email	Create masked email
mail_update_masked_email_state	Enable/disable masked email
mail_download_attachment	Download attachment
mail_upload_attachment	Upload blob for sending

Contacts (contacts_*)

Tool	Description
contacts_list_address_books	List address books
contacts_list	List contacts
contacts_get_contact	Get contact details
contacts_create_contact	Create contact
contacts_update_contact	Update contact
contacts_delete_contact	Delete contact

Calendar (calendar_*)

Tool	Description
calendar_list_calendars	List calendars
calendar_list_events	List events
calendar_get_event	Get event details
calendar_create_event	Create event
calendar_update_event	Update event
calendar_delete_event	Delete event

Files (files_*)

Tool	Description
files_list	List files/folders
files_get	Download file
files_upload	Upload file
files_create_folder	Create folder
files_move	Move/rename file
files_delete	Delete file/folder

Development

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

License

MIT