Apple Calendar MCP

A Claude Desktop extension that gives Claude full access to Apple Calendar on macOS via Apple's first-class EventKit framework. Read, search, create, update, and delete events — including recurring events (edited per-occurrence or for all future occurrences), alarms, structured locations, attendee read-back, and free/busy availability.

Packaged as an MCPB desktop extension with the Calendar.app icon and one-click install.

Companion to the Apple Mail, Apple Reminders, Apple Notes, and Apple Messages connectors.

What it does

Related MCP server: Apple EventKit MCP Server

How it works

Communication with Calendar happens through EventKit (EKEventStore, EKEvent, EKCalendar, EKRecurrenceRule, EKAlarm, EKStructuredLocation) via PyObjC — the same first-class framework Calendar.app itself uses, reading the same local store (including iCloud-, Google-, and Exchange-synced calendars).

This is the same approach as the companion Apple Reminders connector, and differs from the AppleScript/JXA route: EventKit exposes the full data model (recurrence read-back, per-occurrence editing, attendee responses, structured locations) and is dramatically faster. Unlike Reminders, event fetches are synchronous in EventKit, so no async bridging is needed; the one quirk is that the events predicate spans at most ~4 years per query, so wider ranges are chunked transparently.

Recurring events

Occurrences of a recurring event share one stable event_id; each occurrence returned by list_events also carries an occurrence_date. Write tools accept both:

• occurrence_date picks which occurrence you're targeting

• span picks the scope: this_event (just that occurrence, detaching it) or future_events (that occurrence and everything after)

Requirements

• macOS 14 Sonoma or later (requestFullAccessToEvents was added in 14)

• Python 3.11+

• Claude Desktop with extension support

• Calendar permission — Full Access — granted to the extension's uv (see Permissions)

Installation

Option 1: Desktop Extension (recommended)

Download the latest .mcpb from Releases, then double-click to install.

Or build from source:

git clone https://github.com/falconbradley/claude-connector-apple-calendar.git
cd claude-connector-apple-calendar
./build.sh

Then double-click dist/apple-calendar-<version>.mcpb (or drag it into Claude Desktop).

The extension appears in Settings > Extensions with the Calendar icon.

Option 2: Manual MCP config

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "apple-calendar": {
      "command": "uv",
      "args": ["run", "--project", "/path/to/claude-connector-apple-calendar", "apple-calendar-mcp"]
    }
  }
}

Permissions

The first time Claude calls a Calendar tool, macOS will prompt you to grant Calendars access. Choose Full Access — the macOS 14+ "Add Only" grant can't read events back, so every read tool (and the read-back after each write) would fail.

If the prompt doesn't appear (which can happen with unsigned interpreters launched as child processes):

1. Open System Settings → Privacy & Security → Calendars

2. Enable uv with Full Access — not Claude. Claude Desktop launches extension servers through a helper that makes the spawned uv (~/Library/Application Support/Claude/uv-runtime/<version>/uv) responsible for their permissions. The connector's permission error prints the exact path.

3. Quit Claude (⌘Q) and reopen it

To verify access status, run:

sqlite3 ~/Library/Application\ Support/com.apple.TCC/TCC.db \
  "SELECT client, auth_value FROM access WHERE service='kTCCServiceCalendar'"

(auth_value of 2 = full access, 0 = denied. The client is the uv path, not Claude. Reading TCC.db itself needs Full Disk Access for your terminal.)

Using several Apple connectors

This connector is one of a family of Claude Desktop extensions for Apple apps — Mail, Messages, Contacts, Calendar, Reminders, Notes — and they share the same setup quirks:

• Install them one at a time. Opening several .mcpb files at once can leave Claude Desktop showing only the last install dialog, so the others silently never install. Approve each dialog before opening the next, then check Settings → Extensions.

• Permissions belong to uv, not Claude. Claude Desktop launches every extension through the same bundled uv and macOS attributes their privacy grants to it. Full Disk Access granted once to ~/Library/Application Support/Claude/uv-runtime/<version>/uv covers Mail, Notes, Messages, and Reminders together; the Contacts, Calendars, and Reminders panes list the connectors as uv. Permission errors print the exact path in use, ready to paste.

• Re-grant after Claude Desktop updates uv. The <version> folder changes and macOS treats the new binary as a new app. Symptoms: Mail and Notes searches report "engine": "applescript" and get slow, Messages reads and Reminders tags fail with a Full Disk Access error.

• Restart after granting. Quit Claude (⌘Q) and reopen it — macOS reads Full Disk Access only at launch.

• Verify. Ask Claude for each connector's stats (get_stats). For Mail and Notes, a search result's engine should be "sqlite".

Usage examples

Once installed, just ask Claude naturally:

• "What's on my calendar today?"

• "When am I free for an hour tomorrow afternoon?"

• "Schedule lunch with Sam on Friday at noon at Zuni Café."

• "Move my 3pm to 4:30 and make it 45 minutes."

• "Set up a weekly team sync every Tuesday at 10am for the next 8 weeks."

• "Cancel just next Monday's standup, keep the rest of the series."

• "Add a 10-minute-before alert to my dentist appointment."

• "Who hasn't responded to the offsite invite?"

• "Create a 'Travel' calendar and put my flight itinerary on it."

Building from source

# Install mcpb CLI (one time)
npm install -g @anthropic-ai/mcpb

# Install uv (one time, if not already installed)
curl -LsSf https://astral.sh/uv/install.sh | sh

# Build the extension
./build.sh

# Or manually:
mcpb validate manifest.json
mcpb pack . dist/apple-calendar-<version>.mcpb

Project layout

claude-connector-apple-calendar/
├── manifest.json                    # MCPB desktop extension manifest
├── icon.png                         # Calendar.app icon (512x512)
├── icons/                           # Multi-size icons
│   ├── icon-128.png
│   ├── icon-256.png
│   └── icon-512.png
├── pyproject.toml                   # Python package + dependencies
├── build.sh                         # Test, check, and pack build script
├── tools/                           # Dev-only icon extraction (not packed)
├── tests/
│   └── test_e2e.py                  # End-to-end tests
└── src/
    └── apple_calendar_mcp/
        ├── __init__.py
        ├── server.py                # MCP tools (MCPServer)
        ├── calendars.py             # EventKit-backed CalendarStore
        ├── permissions.py           # TCC grant helpers
        └── models.py                # Pydantic data models

Tests

# Static tests (model shapes, validation, helpers — no permission needed)
uv run python tests/test_e2e.py --skip-live

# Full suite (requires Calendar permission)
uv run python tests/test_e2e.py

Live tests operate against a dedicated __claude_mcp_test__ calendar which is created at setup and torn down at the end.

Security & privacy

• All data stays on your Mac — this is a local MCP server. EventKit reads from the same store Calendar.app uses, including iCloud/Google/Exchange-synced calendars.

• Operations gated by macOS TCC: nothing happens until you grant Calendar access.

• macOS-only ("platforms": ["darwin"] in manifest).

• The connector never reaches outside the Calendar entity — no Reminders, contacts, or files.

• Destructive operations (delete_calendar, delete_event) are explicit tools the model must choose to call; they don't run as side effects of reads.

• Creating or modifying events never emails invitations — EventKit's public API can't add attendees, so nothing leaves your machine.

Troubleshooting

"Apple Calendar access was not granted" Open System Settings → Privacy & Security → Calendars, ensure Claude Desktop is listed with Full Access (not "Add Only"), then restart Claude Desktop.

Permission prompt doesn't appear Unsigned Python interpreters launched by Claude Desktop sometimes don't trigger the prompt automatically. Add Claude Desktop manually under System Settings → Privacy & Security → Calendars.

Events beyond ~4 years out don't appear EventKit's events predicate spans at most 4 years per query. The connector chunks wider ranges automatically, but extremely wide ranges will be slow — prefer narrower windows.

A recurring-event edit changed the whole series Pass occurrence_date (from list_events) to target one occurrence, and keep span='this_event'. span='future_events' intentionally rewrites that occurrence and everything after it.

Can Claude invite people to a meeting? No — EventKit's public API exposes attendees read-only. Claude can read who's invited and how they responded, but you add invitees in Calendar.app.

Extension doesn't appear after install Make sure you're running a recent Claude Desktop that supports MCPB extensions. Restart Claude Desktop after installing.

Roadmap

v1 — shipped

• List, create, rename, delete calendars

• List, search, get events with filters and pagination

• Create, update, delete events (span-aware for recurring series)

• Recurrence (daily/weekly/monthly/yearly with intervals, by-day, by-month, set positions, end conditions)

• Alarms (relative, absolute)

• Structured (geocoded) locations

• Attendee and organizer read-back with response status

• Free/busy availability with interval merging

• ical:// deep links

v2 — under consideration

• RSVP / respond-to-invite (blocked on public EventKit API)

• Travel-time and conference-URL read-back where EventKit exposes them

• Bulk operations (move/delete multiple events)

• Natural "find a slot for N people" helper on top of get_availability

Releasing

Every connector in the family releases the same way:

1. Bump the version in pyproject.toml, manifest.json, and src/apple_calendar_mcp/__init__.py, then run uv lock so uv.lock matches. CI fails if the three disagree.

2. Add a section for the version to CHANGELOG.md.

3. Commit, tag vX.Y.Z, and push the tag: git push origin main vX.Y.Z.

The release workflow then checks the tag matches all three version files, runs ./build.sh (tests, manifest and tool checks, pack), and publishes apple-calendar-X.Y.Z.mcpb to a GitHub release whose notes are that version's CHANGELOG section.

License

MIT