The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Apple Calendar listing page.
An MCP server that lets an AI assistant read and create events in Apple Calendar — and work out when you actually have time.
macOS only. It talks to EventKit, Apple's own calendar framework, which has no cross-platform equivalent.
No Xcode, no Swift toolchain, no repository clone. The signed helper binary ships inside the package.
Most calendar integrations answer what is on my calendar. This one also answers when am I free:
find_free_time returns the open gaps, not the busy blocks. It understands
that "work" means weekdays during working hours, that "personal" means any
day, and that all-day events usually shouldn't count as busy.
It can also keep a buffer around each meeting, because a gap wedged directly between two calls is free on paper and useless in practice.
Alongside that, the usual: list calendars, read events in a range with optional text search, create, update and delete events with location, notes, alarms, all-day or timed. Recurring events come back as individual occurrences, not as the master event — a detail AppleScript-based servers routinely get wrong.
Changing or deleting an occurrence of a recurring event requires saying explicitly whether you mean just that one or every later one too. There is no default for that, because "cancel this Tuesday" and "never again" are not the kind of thing to guess at.
Full parameter reference: docs/tools.md.
Nothing else. Building from source additionally needs Xcode Command Line Tools, but installing from npm does not.
1. Add the server to your client.
Quit Claude Desktop first (Cmd+Q) — it rewrites its config on exit, so
editing while it runs discards your change. Then add to
~/Library/Application Support/Claude/claude_desktop_config.json:
Any client that speaks MCP over stdio works. The command is npx, the
arguments are -y @redpop/apple-calendar-mcp, and no environment variables
are needed.
2. Grant calendar access on first use.
Ask your assistant "what calendars do I have?". A system dialog appears asking to let calendar-helper — not your assistant, the helper itself — access your calendar.
Confirm it, then open System Settings → Privacy & Security → Calendars → calendar-helper → Options… and make sure Full Access is selected, not "Add Only". Read-only access is not enough; the helper checks for full access at startup.
This one dialog is the only manual step, and no package format can take it away. It appears once and survives updates.
macOS grants calendar permission to the responsible parent process, not to the program actually asking. An AI client that declares no calendar usage in its bundle therefore locks out everything it starts — silently, with no dialog and no entry in System Settings. Several MCP calendar servers work around this by telling you to launch your client from a terminal.
This one doesn't need that. The helper disclaims that inherited responsibility at startup and becomes its own permission identity, so macOS reads the usage description from its bundle and prompts under its own name. One grant then covers every client on the machine.
The full story: docs/architecture.md.
Your calendar grant survives updates: the helper is installed to a fixed path, and macOS binds the grant to that path rather than to the binary's contents.
Remove the apple-calendar entry from your client's MCP configuration and
restart it. Then delete the helper and its permission:
The entry under System Settings → Privacy & Security → Calendars stays behind — macOS keeps those even when the binary is gone. Switch it off there if you want it revoked.
Then point your client at dist/index.js with node instead of using npx.
Without a Developer ID certificate the helper is signed ad-hoc, and macOS
then ties the calendar grant to the exact build — expect a new permission
dialog after every rebuild.
docs/architecture.md — how the two halves fit
together and the whole TCC permission storydocs/tools.md — every tool parameter, defaults, and
the all-day alarm ruledocs/cli.md — the standalone calendar-helper command,
useful for testing without an MCP clientdocs/troubleshooting.md — common errors and
how to fix themEverything runs locally. Calendar data goes from EventKit to the helper to the MCP server to your client, and nowhere else. There is no network code in this project.
MIT — see LICENSE.