Apple Events MCP Server

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A Model Context Protocol (MCP) server providing native integration with Apple Reminders and Calendar on macOS via the EventKit framework. Exposes reminders, lists, subtasks, and calendar events through a standardized interface with full CRUD operations.

The EventKit backend is the standalone event Swift CLI, vendored as a git submodule and built into bin/event during pnpm install — no separate brew install required. See docs/migration-to-event-cli.md for the v1.5.0 backend swap and the list of write fields not yet exposed by event.

Table of Contents

• Features
• Prerequisites
• Quick Start
• Configuration
• macOS Permissions
• Usage Examples
• Available MCP Tools
• Structured Prompt Library
• Development
• License
• Contributing

Features

• Full CRUD for reminders, subtasks, reminder lists, and calendar events
• Priority (high/medium/low/none), tags, and checklist subtasks with progress tracking
• Multi-criteria filtering: completion, due-date range, priority, tags, full-text search, recurring, location-based
• Flexible date formats (YYYY-MM-DD, YYYY-MM-DD HH:mm:ss, ISO 8601) with timezone awareness
• Native macOS integration via EventKit — values configured in Reminders.app / Calendar.app round-trip through read responses
• Automatic macOS permission discovery and prompting
• Full Unicode support with comprehensive input validation

Prerequisites

• Node.js 20 or later
• macOS (required for EventKit)
• Xcode Command Line Tools (only when building from source)
• pnpm (recommended)

The published npm package ships a pre-built, universal, code-signed bin/event binary, so npx users need neither Xcode nor a Swift toolchain. Building from a git clone requires the items above.

Quick Start

npx mcp-server-apple-events

Configuration

Add the server to your MCP client. The npx form works for every client below; for a local build, replace command/args with node pointing at dist/index.js.

Cursor

Settings → MCP → Add new global MCP server:

{
  "mcpServers": {
    "apple-reminders": {
      "command": "npx",
      "args": ["-y", "mcp-server-apple-events"]
    }
  }
}

ChatWise

Settings → Tools → "+", then:

• Type: stdio
• ID: apple-reminders
• Command: mcp-server-apple-events
• Args: (empty)

Claude Desktop

Edit claude_desktop_config.json (open it via Settings → Developer Option → Edit Config, or directly at ~/Library/Application Support/Claude/claude_desktop_config.json on macOS / %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "apple-reminders": {
      "command": "npx",
      "args": ["-y", "mcp-server-apple-events"]
    }
  }
}

For a local build:

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

See the official MCP docs for connecting local servers. Restart Claude Desktop completely (quit, not just close) for changes to take effect.

macOS Permissions

The vendored event CLI embeds its own Info.plist (bundle id me.frad.event) declaring all Reminders and Calendar privacy strings, and is spawned through the bundled bin/event-disclaim shim, which disclaims TCC responsibility at spawn time. macOS therefore attributes the permission request to event itself, not the app that launched the MCP server — so the first EventKit call prompts for "event", the grant appears under System Settings > Privacy & Security > Reminders / Calendars as event, and one grant covers every MCP client on the machine (Claude Desktop, Codex Desktop, Cursor, terminal clients, …). See issue #93 for background.

When event detects a notDetermined status it calls requestFullAccessToReminders / requestFullAccessToEvents, which surfaces the system prompt. If the OS ever loses track of permissions, rerun ./check-permissions.sh to re-open the dialogs.

Calendar read errors

If you see Failed to read calendar events, set Calendar to Full Calendar Access under System Settings > Privacy & Security > Calendars, or rerun ./check-permissions.sh (it checks both Reminders and Calendars).

Recovering a stuck TCC state (no prompt ever appears)

If the permission dialog never appears and event is missing from System Settings → Privacy & Security → Reminders / Calendars, your machine is in a stale/misattributed TCC state. The server-side disclaim fix prevents this on a clean machine but cannot clear already-corrupted entries. Recovery:

1. Reset Calendar and Reminders TCC entries globally (per-app reset frequently does not work — the bare form clears all entries, which is what clears the bad state):

   bash

   Copy

   tccutil reset Calendar
   tccutil reset Reminders
   

   This clears Calendar/Reminders access for every app; other apps re-prompt next time.

2. Re-trigger the permission from inside a Claude conversation (Claude Desktop or Claude Code) by asking, e.g., "Use AppleScript to check my Calendar and Reminders." Grant access and the server should work normally. See issue #83.

Headless / launchd runs hang instead of failing

When the server runs from a context with no GUI session (SSH, launchd agent/daemon), the first EventKit call can block forever waiting on a permission prompt that can never be rendered — the MCP request never settles and a child process leaks per call. The server now kills any event call that exceeds 30 s (SIGKILL) and returns a readable error instead. Tune it with the EVENTKIT_CLI_TIMEOUT_MS environment variable (milliseconds; invalid/zero values fall back to the default — the timeout cannot be disabled, though huge values up to 2^31-1 ms are accepted). The vendored event CLI (pinned via FradSer/event#15) additionally fails fast when no GUI session exists and gives up on an unanswerable prompt after 15 s (EVENT_PERMISSION_TIMEOUT_MS), reporting Permission denied: Timed out waiting for ... so the host can show a permission-specific message before the server's kill fires (15 s < 30 s). See issue #113.

macOS 26 (Tahoe) could not build module 'Foundation'

If pnpm build fails with could not build module 'Foundation' (or SDK is not supported by the compiler), your Swift toolchain is older than the macOS 26 SDK requires — it needs Swift 6.3 or newer, but the Command Line Tools shipped with early macOS 26 point releases include Swift 6.2.x. pnpm build:event detects this and prints the same remediation; see issue #85. Fix by installing Xcode 26.x from the App Store, or updating Command Line Tools to a Swift 6.3+ version:

softwareupdate --list
sudo softwareupdate -i "Command Line Tools for Xcode-<latest>"
sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer   # if full Xcode is installed
xcrun swiftc --version    # should report Apple Swift version 6.3 or newer

Usage Examples

Once configured, ask Claude to interact with your Apple Reminders and Calendar. Example prompts:

Create a reminder to "Buy groceries" for tomorrow at 5 PM with tags shopping and errands.
Add a high-priority reminder to "Finish quarterly report" due Friday in my "Work" list.
Create "Grocery shopping" with subtasks: milk, eggs, bread, butter.
Show me all high-priority reminders due today tagged "urgent".
Show subtasks for my "Grocery shopping" reminder and mark "milk" as complete.
Update "Buy groceries" — change the title to "Buy organic groceries" and set priority to high.
Show reminders from my "Work" list, and list all my reminder lists.
Create a calendar event "Team standup" tomorrow from 9:00 to 9:30 in "Work".
Show my calendar events for the next week.
Invite alex@example.com to my "Team standup" event.
Cancel just the September 21 occurrence of my weekly "Team standup".

The server processes natural-language requests, interacts with Apple's native Reminders and Calendar apps, and returns formatted results.

Alarms, recurrence rules, and location triggers are read-only via this server — configure them in Reminders.app / Calendar.app. They still appear in read results with visual indicators.

Available MCP Tools

Service-scoped tools mirror Apple Reminders and Calendar domains. All take an action field plus action-specific parameters (the MCP client introspects the full Zod schema; only actions are listed here). Date fields accept YYYY-MM-DD, YYYY-MM-DD HH:mm:ss (local time), or ISO 8601 with timezone.

Example calls:

{
  "action": "create",
  "title": "Buy groceries",
  "dueDate": "2024-03-25 18:00:00",
  "targetList": "Shopping",
  "note": "Don't forget milk and eggs",
  "priority": 1,
  "tags": ["shopping", "errands"],
  "subtasks": ["Milk", "Eggs", "Bread"]
}

{ "action": "read", "filterList": "Work", "dueWithin": "today", "filterPriority": "high", "filterTags": ["urgent"] }

{ "action": "read", "startDate": "2026-08-01", "endDate": "2026-08-31" }

{ "action": "update", "id": "reminder-123", "completed": false, "addTags": ["followup"] }

{ "action": "toggle", "reminderId": "reminder-123", "subtaskId": "a1b2c3d4" }

{ "action": "create", "name": "Project Alpha" }

{ "action": "create", "title": "Team standup", "startDate": "2026-05-04 09:00:00", "endDate": "2026-05-04 09:30:00", "targetCalendar": "Work" }

{ "action": "update", "id": "event-123", "attendees": ["alex@example.com", "sam@example.com"] }

{ "action": "delete", "id": "event-123", "occurrenceDate": "2026-09-21T09:00:00" }

Attendees and single occurrences

These two calendar_events parameters are the only writes that do not go through the event CLI, because EventKit cannot express either one. Each needs setup the rest of the server does not.

attendees (update) — invites email addresses to an existing event. EKCalendarItem.attendees is read-only in the macOS SDK and EventKit has no invitation API, so the write goes through Calendar.app's scripting interface; adding the attendee locally is what makes iCloud send the invitation.

• Requires an Automation grant: the first call prompts, and the entry appears under System Settings > Privacy & Security > Automation. Needs a GUI session, so it does not work headless.
• Attendees must be updated alone. They travel through Calendar.app while every other field travels through EventKit, and the two share no concurrency token — a combined update has no safe ordering, so it is refused. Issue two calls.
• Two events sharing a title and a start date are refused, not guessed between. Calendar.app can only be queried by title and date, and writing to the wrong one would send a real invitation for it.

occurrenceDate (delete) — excepts one occurrence of a recurring series. Every occurrence shares one EventKit identifier, so span: "this-event" can only ever except the series start; aimed at a later occurrence it writes nothing and still reports success. Supplying occurrenceDate routes the delete over CalDAV, which can address the instance directly.

• Requires iCloud credentials. Set ICLOUD_APPLE_ID and ICLOUD_APP_PASSWORD, or set ICLOUD_APPLE_ID and store the password in the Keychain:

  bash

  Copy

  security add-generic-password -a "you@icloud.com" -s "icloud-caldav-mcp" -w
  

  Use an app-specific password, never your account password. Credentials are read from the environment first, then the Keychain, never from MCP client config, and are never logged.

• Only iCloud-synced events qualify — an event with no external identifier has no CalDAV resource to locate.

Read response shape

Read responses carry visual indicators: 🔄 recurring, 📍 location-based, 🏷️ has tags, 📋 has subtasks. Example:

- [ ] Buy groceries 🏷️📋
  - List: Shopping
  - ID: reminder-123
  - Priority: high
  - Tags: #shopping #errands
  - Subtasks (1/3):
    - [x] Milk
    - [ ] Eggs
    - [ ] Bread
  - Due: 2024-03-25 18:00:00

The url field is stored in the native url property (visible via the "i" icon in Reminders.app) and also appended to the notes in a structured URLs: block for parsing and multi-URL support. URLs accept any valid URI scheme (http, https, mailto, tel, obsidian, shortcuts, …); file, javascript, data, and similar dangerous schemes are rejected, and http(s) hostnames are checked against an SSRF blocklist.

Read-only fields: alarms, recurrence rules, location triggers, structured locations, calendar url/availability/isAllDay, and cross-calendar moves are not writable via this server — they round-trip from values configured in Reminders.app / Calendar.app. See docs/migration-to-event-cli.md for the full dropped-field table and workarounds.

Structured Prompt Library

The server ships a prompt registry exposed via the MCP ListPrompts / GetPrompt endpoints. Each template shares a mission, context inputs, numbered process, constraints, output format, and quality bar so downstream assistants get predictable scaffolding.

• daily-task-organizer — optional today_focus; produces a same-day execution blueprint, balances priority work with recovery, auto-creates calendar time blocks for due-today reminders.
• smart-reminder-creator — optional task_idea; generates an optimally scheduled reminder structure.
• reminder-review-assistant — optional review_focus (e.g. overdue or a list name); audits and optimizes existing reminders.
• weekly-planning-workflow — optional user_ideas; guides a Monday-through-Sunday reset with time blocks tied to existing lists.

Prompts are constrained to native Apple Reminders capabilities and ask for missing context before irreversible actions. Run pnpm test -- src/server/prompts.test.ts after amending prompt copy.

Development

pnpm install        # postinstall builds bin/event from vendor/event on macOS
pnpm build          # TypeScript + vendored event CLI
pnpm test           # Jest suite: repositories, schemas, build script, prompt templates
pnpm exec biome check   # lint + format

The CLI entry point walks up to ten directories to find package.json, so the server can start from nested paths (e.g. dist/ or editor task runners) without losing bin/event. Keep the manifest reachable within that depth if you customize the folder layout.

Scripts

• pnpm build — TypeScript + vendored event CLI (required before running from source)
• pnpm build:ts — TypeScript only
• pnpm build:event — vendored event CLI only (swift build -c release → bin/event)
• pnpm build:release — build plus notarization (release packaging)
• pnpm test / pnpm test:ci — Jest suite / with coverage
• pnpm lint — Biome format/fix + TypeScript type check
• pnpm check — lint + tests with coverage

License

MIT

Contributing

Contributions welcome! Please read the contributing guidelines first.