jmap-calendar-mcp

An MCP server that lets an AI agent see your calendars, find events, and create, change or (if you allow it) delete events on any JMAP server that supports JMAP for Calendars, such as Stalwart 1.0 and later.

One Python file, standard library only.

Tools

Built to be safe to hand to an agent:

• No delete by default. An agent can move or rename an event but cannot remove one. Set JMAP_ALLOW_DELETE=1 to offer delete_calendar_event; it sends no cancellations.
• No invitations by default. Attendees are added without being emailed. Sending invitations needs both JMAP_ALLOW_INVITES=1 on the server and send_invitations: true on the call.
• Use a key with calendar permissions only, so the agent cannot read or send mail through it.

Setup

1. Create an API key for the account. On Stalwart, open the account in the admin (Directory → Accounts), set the key's permissions to Replace all permissions, and give it only these:

   • Sign in to the server
   • JMAP: Retrieve calendar details and properties
   • JMAP: Track changes to calendars since a given state
   • JMAP: Retrieve calendar event details
   • JMAP: Track changes to calendar events since a given state
   • JMAP: Search for calendar events matching criteria
   • JMAP: Track changes to calendar event query results
   • JMAP: Create new calendar events
   • JMAP: Modify existing calendar events
   • JMAP: Remove calendar events (only if you set JMAP_ALLOW_DELETE=1)

   The key then cannot read or send mail.

2. Add the server to your MCP client. For Claude Code:

claude mcp add calendar \
  -e JMAP_SESSION_URL=https://mail.example.com/.well-known/jmap \
  -e JMAP_BEARER_TOKEN=your-api-key \
  -- uvx jmap-calendar-mcp

For several accounts, add one server per account (calendar-work, calendar-home).

Keep the key out of shell history and config files where you can: load it from your password manager or secret store when the server starts.

License

MIT