Apple Calendar MCP

Apple Calendar MCP lets an AI assistant read and change your Apple Calendar. It is one small Swift program that works two ways: as an ical command you can run in the terminal, and as an MCP server that AI apps like Claude can plug into. Either way it talks to the calendar database on your Mac directly, so answers come back in about a tenth of a second, Calendar.app never has to open, and nothing leaves your machine.

What it does

• Ask what is on your calendar today, this week, or over the next few days, across all calendars or just one.
• Create, update, and delete events from the terminal or from any MCP-compatible AI app.
• Set up once with a single config block and the calendar shows up as a tool the assistant can use.

Two ways to connect

• On the same Mac. The AI app launches the binary directly. No network, no login, nothing else to configure.
• From another machine. The same binary can run as a small HTTP server on your private network, so a laptop or a remote coding session can reach the same calendar. Every client gets its own token, and any token can be revoked while the server keeps running.

Decisions worth knowing

• It fails closed. The network server refuses to start if no token is configured. Better not to run than to run open.
• The permission sticks. macOS asks for calendar access once. The binary is signed with a fixed identity so that grant survives rebuilds and upgrades instead of prompting again every time.
• It is tested. An XCTest suite covers auth, token storage, date parsing, and the HTTP server, and runs in CI on every push.

It installs through a Homebrew tap that builds and signs it in one command, with one more to run it in the background.