calendar-mcp

MCP server that gives Claude (and other MCP hosts) full access to Calendar.app on macOS — list, search, create, update, and delete events — across every account configured in Calendar.app (iCloud, Google, Exchange, etc.).

Prerequisites

• macOS (Calendar.app required)
• Node.js 20+
• An MCP host: Claude Desktop or any stdio MCP client

Installation

Claude Desktop — one-click install (recommended)

1. Download calendar-mcp.mcpb from the latest release
2. Double-click the .mcpb file — Claude Desktop installs it automatically
3. Grant the required macOS permissions (see below)

Manual / other hosts

npx @p-l-ta/calendar-mcp

Or install globally:

npm install -g @p-l-ta/calendar-mcp
calendar-mcp

Point your MCP host at the calendar-mcp binary (stdio transport). Example config:

{
  "mcpServers": {
    "calendar-app": {
      "command": "npx",
      "args": ["@p-l-ta/calendar-mcp"]
    }
  }
}

Required macOS permissions

Grant these to the application that runs the MCP host (Claude Desktop, etc.):

Permission	Where to grant
Full Disk Access	System Settings → Privacy & Security → Full Disk Access
Automation → Calendar	System Settings → Privacy & Security → Automation

The MCP server process inherits permissions from the host application that launches it.

Tools

Tool	Description
list_calendars	List all calendars with name, color, account, and UUID
list_events	List events in a date range, including recurring-event occurrences
get_event	Get full details of a single event by UUID, including attendees
search_events	Search events by text across title, description, and location
create_event	Create a new calendar event
update_event	Update properties of an existing event
delete_event	Permanently delete an event

How it works

• Reads (list_calendars, list_events, search_events, get_event) — query Calendar's SQLite database directly for fast, structured results across all accounts. Recurring events are expanded correctly via Calendar's OccurrenceCache table.
• Writes (create_event, update_event, delete_event) — driven by AppleScript automation against Calendar.app, so changes sync to all connected accounts (iCloud, Google, Exchange) just as if you'd made them in the app.

Development

npm install
npm run dev          # tsx watch — live reload
npm run build        # compile TypeScript → dist/
npm run mcpb         # build Claude Desktop extension → build/calendar-mcp.mcpb
npm run smoke        # smoke-test all 7 tools against live Calendar.app data

Note: npm run smoke requires Terminal.app (or your terminal emulator) to have Full Disk Access, since it reads Calendar.sqlitedb directly.

Interactive MCP testing:

npm run build
npx @modelcontextprotocol/inspector node dist/server.js

Privacy Policy

calendar-mcp is a local MCP server that runs entirely on your Mac. It has no backend, no telemetry, and makes no network requests of its own.

What it accesses:

• Calendar's SQLite database (~/Library/Group Containers/group.com.apple.calendar/Calendar.sqlitedb) — read-only, used for list/search queries
• Calendar.app via AppleScript — to create, update, and delete events

What it does NOT do:

• Collect, store, or transmit any data outside your Mac
• Connect to any external server or API
• Log calendar data anywhere

All calendar data stays on your device and is only passed to the MCP host (Claude Desktop or another client) as part of normal tool responses. You control exactly which tools Claude can invoke.

License

MIT