apple-calendar-mcp

A local MCP server that lets Claude read and create events in Apple Calendar on macOS. macOS only — it uses Apple's EventKit framework, which has no cross-platform equivalent.

What Claude can do with it

• List your calendars — see every calendar configured in Calendar.app, including iCloud calendars.

• List events in a time range, with optional text search.

• Create a new event — title, time, location, notes, alarms, all-day or timed.

• Find free time — get open slots of a given length, restricted to working hours, personal hours, or any time at all.

Full details, including all parameters: docs/tools.md.

Related MCP server: Nextcloud CalDAV MCP Server

Requirements

• macOS 14 (Sonoma) or newer

• Node.js 20 or newer

• Xcode Command Line Tools (xcode-select --install) — a full Xcode install is not needed

Installation

Run these from the root of this repository, in order.

1. Install and build.

npm install
npm run build
./swift/build.sh

This installs the Node dependencies, compiles the TypeScript server to dist/, and compiles + signs the Swift calendar helper to bin/calendar-helper.

2. Register the background helper.

bash launchagent/install.sh

This installs the helper as a per-user background service that starts automatically at login, and waits for it to come up.

3. Grant calendar access.

A system dialog appears, asking to let calendar-helper access your calendar. Click OK, then open System Settings → Privacy & Security → Calendars → calendar-helper → Options… and make sure Full Access is selected, not "Add Only". Re-run bash launchagent/install.sh afterwards if it hadn't already reported success.

4. Configure Claude Desktop.

Quit Claude Desktop first (Cmd+Q). It rewrites its own config file on exit, so editing it while Claude Desktop is still running gets your change silently discarded.

Then add this to ~/Library/Application Support/Claude/claude_desktop_config.json, replacing the path with the absolute path to dist/index.js in this checkout:

{
  "mcpServers": {
    "apple-calendar": {
      "command": "node",
      "args": ["/absolute/path/to/apple-calendar-mcp/dist/index.js"]
    }
  }
}

5. Start Claude Desktop again.

It only reads the config file on startup, so this is what picks up the new server.

Did it work?

Ask Claude "what calendars do I have?" It should list your calendars. If instead you get a permission error or no tools appear, see docs/troubleshooting.md.

Updating after code changes

./swift/build.sh && bash launchagent/install.sh

With a Developer ID certificate, your calendar grant survives this. Without one, expect a fresh permission dialog every time.

Uninstalling

bash launchagent/uninstall.sh

This stops and removes the background service. It does not revoke the calendar grant itself — do that in System Settings if you want it gone too.

Learn more

• docs/architecture.md — how the pieces fit together, and why a background service is required at all (the whole TCC permissions story).

• docs/tools.md — full MCP tool reference: every parameter, defaults, and the all-day alarm rule.

• docs/cli.md — the standalone calendar-helper command-line tool, useful for testing without an MCP client.

• docs/troubleshooting.md — common errors and how to fix them.

License

MIT — see LICENSE.