apple-calendar-mcp

A local MCP server that gives Claude full CRUD access to the macOS Calendar and Reminders via Apple's EventKit framework — including real recurring-event operations.

Everything runs on your Mac. No cloud, no accounts, no external services — your calendar and reminder data never leaves the machine.

Requirements

• macOS (uses EventKit / the native Calendar database)
• Python 3.10+ (the MCP SDK requires it)
• An MCP client — these instructions cover Claude Desktop

Tools

Tool	What it does
list_calendars	All calendars: id, title, source, color, writable, default
list_events	Events in a date range, recurring events expanded to occurrences
get_event	Full detail for one event / occurrence
create_event	New event, optionally recurring
update_event	Change any field; retarget/reshape recurrence
delete_event	Delete one occurrence, "this and future", or the whole series
detach_occurrence	Make a standalone, non-recurring copy off a recurring series
create_calendar	New calendar in a chosen source, optional color
set_calendar_color	Recolor a calendar (hex, e.g. #FF3B30)
delete_calendar	Permanently delete a calendar + its events (guarded, id-only)

Note on colors: Apple Calendar has no per-event color — events inherit their calendar's color. So coloring happens at the calendar level; there's no event-color tool because EventKit exposes no such property.

Reminders tools

Tool	What it does
list_reminder_lists	All reminder lists: id, title, color, writable, default
list_reminders	Reminders, filterable by list, completion, and due-date window
get_reminder	Full detail for one reminder
create_reminder	New reminder (due date, priority, notes, url, optional recurrence)
update_reminder	Change any field; mark complete/incomplete; reshape recurrence
delete_reminder	Permanently delete a reminder

Reminders support the same recurrence spec as events, priority is none/low/medium/high, and due accepts a date (2026-08-10, no time-of-day) or a datetime (2026-08-10T14:30).

Working with recurring events

list_events returns each occurrence with its event_id and its own start. To act on a specific occurrence, pass that start back as occurrence_start, plus a span:

• this — only that occurrence (detaches it from the series)
• future — that occurrence and every later one
• all — the entire series

Change how an event recurs by passing a new recurrence spec to update_event; turn a series into a one-off with clear_recurrence=True.

Recurrence spec shape:

{
  "frequency": "weekly",            // daily | weekly | monthly | yearly
  "interval": 2,                    // every N periods
  "days_of_week": ["MO","WE","FR"], // weekly only
  "days_of_month": [1, -1],         // monthly only (-1 = last day)
  "count": 10,                      // total occurrences  (or)
  "end_date": "2026-12-31"          // stop after this date
}

Install

git clone https://github.com/maxiscoding28/apple-calendar-mcp.git
cd apple-calendar-mcp
python3 -m venv .venv
.venv/bin/python -m pip install -r requirements.txt

Use any Python 3.10+ interpreter to create the venv. If your default python3 is older, substitute a newer one (e.g. python3.12 -m venv .venv).

Connect to Claude Desktop

Add the server to your claude_desktop_config.json. You can open it from Claude Desktop via Settings → Developer → Edit Config, or find it at:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

Add an apple-calendar entry under mcpServers, using absolute paths to the Python interpreter in your venv and to server.py:

{
  "mcpServers": {
    "apple-calendar": {
      "command": "/absolute/path/to/apple-calendar-mcp/.venv/bin/python",
      "args": ["/absolute/path/to/apple-calendar-mcp/server.py"]
    }
  }
}

Replace /absolute/path/to/apple-calendar-mcp with wherever you cloned the repo (run pwd in the project directory to get it). Then fully quit and reopen Claude Desktop so it picks up the change.

Permissions (the one gotcha)

The first time a tool runs, macOS shows a "Claude wants to access Calendar" prompt — approve it. Reminders are a separate permission, so the first time you use a reminders tool you'll get a second "Claude wants to access Reminders" prompt. Both grants are tied to the app that launches the server (Claude Desktop), not to Python.

If it was denied, re-enable it under System Settings → Privacy & Security → Calendars, enable your MCP client, then fully quit and reopen it.

Try it

Ask Claude things like:

• "What's on my calendar this week?"
• "Move my 3pm Friday meeting to 4pm and add a location."
• "Create a standup every weekday at 9am for the next two weeks."
• "Delete just next Tuesday's occurrence of that standup."

See DEMO.md for a copy-paste prompt that exercises every tool on a self-cleaning scratch calendar — safe to run against a real account.

How it works

server.py is a single-file FastMCP server that talks to EventKit through PyObjC. It speaks MCP over stdio, so any stdio-capable MCP client can use it — Claude Desktop is just the documented example.

License

MIT — see LICENSE.