apple-calendar-mcp

MCP server for Apple Calendar via native EventKit API with proper recurring event support.

Why This Exists

AppleScript-based calendar integrations fail to correctly expand recurring events — they return the master event instead of individual occurrences. This project uses Apple’s native EventKit framework with predicateForEvents, which properly expands recurring events into their individual occurrences within a date range.

Architecture

Claude Code ──stdio JSON-RPC──▶ TypeScript MCP Server ──execa──▶ Swift CLI (apple-bridge) ──EventKit──▶ macOS Calendar

• TypeScript layer — MCP server with 6 tools, Zod validation, JSON-RPC over stdio
• Swift layer — CLI binary using EventKit, returns JSON envelope {status, data, error}

Prerequisites

• macOS 13+ (Ventura or later)
• Swift 5.9+ (included with Xcode 15+)
• Node.js 20+

Installation

Option 1: npm (recommended)

claude mcp add --scope user apple-calendar -- npx apple-calendar-mcp

This will automatically download the package, compile the Swift bridge, and register the MCP server. Requires macOS with Xcode or Swift toolchain installed.

After installation, grant calendar access:

npx apple-calendar-mcp doctor

Grant Full Access when prompted. If access was previously denied:

tccutil reset Calendar
npx apple-calendar-mcp doctor

Option 2: From source

git clone https://github.com/EgorKurito/apple-calendar-mcp.git
cd apple-calendar-mcp
./scripts/build.sh

Grant calendar access:

swift/.build/release/apple-bridge doctor

Connect to Claude Code using one of these methods:

Project-level .mcp.json

Copy .mcp.json.example to .mcp.json in your project and update paths:

{
  "mcpServers": {
    "apple-calendar": {
      "command": "node",
      "args": ["/path/to/apple-calendar-mcp/build/index.js"],
      "env": {
        "APPLE_BRIDGE_BIN": "/path/to/apple-calendar-mcp/swift/.build/release/apple-bridge"
      }
    }
  }
}

User-level CLI registration

claude mcp add --scope user apple-calendar \
  node /path/to/apple-calendar-mcp/build/index.js \
  -e APPLE_BRIDGE_BIN=/path/to/apple-calendar-mcp/swift/.build/release/apple-bridge

MCP Tools

Verification

# Check system diagnostics
swift/.build/release/apple-bridge doctor

# List calendars
swift/.build/release/apple-bridge calendars

# Today's events
swift/.build/release/apple-bridge today

# Events in a date range (recurring events expanded)
swift/.build/release/apple-bridge events --start "2026-02-01T00:00:00Z" --end "2026-02-28T23:59:59Z"

Troubleshooting

Calendar access denied Reset TCC permissions and re-run:

tccutil reset Calendar
swift/.build/release/apple-bridge doctor

Recurring events not expanding This is the exact problem this project solves. Ensure you’re using the MCP tools (which use predicateForEvents) rather than AppleScript-based alternatives.

ISO 8601 parse error The Swift binary expects dates in format 2026-02-07T10:00:00Z or 2026-02-07T10:00:00.000Z.

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Run ./scripts/build.sh to verify the build
5. Submit a pull request

License

MIT