🍮 Oreo Pudding: Apple Calendar CalDAV MCP Server

An enterprise-grade Model Context Protocol (MCP) server built with Bun that connects LLM clients (such as Claude Desktop and Poke at poke.com) to Apple Calendar (iCloud) via CalDAV. Designed with strict Domain-Driven Design (DDD), CQRS, and Gang of Four (GoF) design patterns.

🚀 Key Features

• ⚡ Native CalDAV Protocol Sync: Full support for listing calendars, retrieving events, creating, moving/rescheduling, and updating events directly on Apple iCloud servers.

• 📍 Auto-Discovery & Intelligent Routing: Automatically resolves iCloud user principals, calendar-home-sets, and lists calendars under the hood. For commands missing a calendar path, it employs an intelligent scoring heuristic to automatically pick the most suitable default calendar (e.g., scoring Home or Personal highest).

• ⏰ Timezone-Aware Parser: Native handling of timezone normalizations. Defaults to America/Chicago (configurable). Correctly parses floating/local ISO-8601 datetimes without timezone indicators inside the context of the target IANA timezone using TimeZoneHelper, preventing incorrect offset shifts.

• 💨 Stale-While-Revalidate (SWR) Cache: Low-latency responses utilizing in-memory SWR caching for both calendar lists (48h TTL) and events (5m TTL) inside CalDavRepository. Spawns asynchronous background fetches on cache hits to guarantee fresh data without blocking execution.

• 🔌 Dual Transport Mode: Supports both standard I/O streams (stdio) for local integration and Web Standard HTTP SSE (text/event-stream) for remote/network hosting.

• 🖥️ Embedded Interactive Testing Dashboard: Built-in modern glassmorphic Vue 3 testing dashboard served on /dashboard (when running in SSE mode). Includes a live JSON-RPC logger to inspect commands and events in real time.

• 🛡️ Bearer Token Authorization: Option to secure the SSE server using static Bearer token authorization headers.

🛠️ Architecture Overview

The codebase is built on clean architectural principles, enforcing a strict inward dependency flow: Interface ➔ Application ➔ Infrastructure ➔ Domain

For a deep dive into the patterns used, check out the Architecture Documentation.

Design Patterns Utilized

• DDD (Domain-Driven Design): Pure domain entity layers with strict invariants (Tool, ToolId, ToolName, ToolDescription, ToolSchema).

• CQRS: Isolation of state-mutating commands (e.g., CreateCalendarEventCommand, MoveCalendarEventCommand) from read-only queries (e.g., RetrieveCalendarEventsQuery, ListCalendarsQuery).

• Mediator: Dispatching of CQRS messages via a decoupled Mediator bus using Mediator.

• Strategy: Abstract tool strategy executors allowing customizable behavior per registered tool.

• Observer (Domain Events): Broadcast of domain lifecycle occurrences (e.g., event saved, event moved) through an asynchronous event dispatcher.

• Decorator: Logging, performance timing, and schema validation cleanly wrapped around use-case handlers.

⚙️ Environment Configuration

Create a .env file in the root directory (Bun loads this automatically):

# iCloud credentials
APP_ID="your-apple-id@icloud.com"
APP_PASS="xxxx-xxxx-xxxx-xxxx" # iCloud App-Specific Password

# Optional: Server configuration for SSE mode
PORT=3000
BEARER_TOKEN="your-secure-bearer-token"

📦 Installation & Running

Ensure you have Bun installed.

1. Install Dependencies

bun install

2. Run in Standard I/O (stdio) Mode (Default)

This mode is ideal for local integrations (e.g., Claude Desktop):

bun run index.ts

3. Run in SSE (Server-Sent Events) Mode

Starts an HTTP server on the designated PORT:

PORT=3000 bun run index.ts

🖥️ Interactive Testing Dashboard

When running in SSE Mode, you can access the visual testing dashboard.

1. Start the server:

   PORT=3000 bun run index.ts

2. Open your browser and navigate to http://localhost:3000/dashboard (or http://localhost:3000/dashboard.html).

3. Set your Authorization Header using your BEARER_TOKEN (if configured) or connect directly.

4. Interact with the server: list calendars, view event timelines, create new events, and view live JSON-RPC request/response payload logs in the terminal console.

🛠️ Available MCP Tools

The server exposes the following tools to MCP-compatible client applications (configured in index.ts):

1. list_calendars

Lists all available calendars for the authenticated iCloud account.

• Arguments: None

2. retrieve_calendar_events

Retrieves events from the primary/default calendar within a specified date range.

• Arguments:

  • startDate (string, optional): Start datetime in ISO 8601 format. If omitted, defaults to the start of the current day.

  • endDate (string, optional): End datetime in ISO 8601 format. If omitted, defaults to 24 hours from startDate.

  • timezone (string, optional): IANA timezone identifier (e.g., America/Chicago). Output datetimes will be formatted in this timezone.

3. retrieve_all_calendar_events

Retrieves events across all calendars for the account in a single query.

• Arguments:

  • startDate (string, optional): ISO 8601 start date.

  • endDate (string, optional): ISO 8601 end date.

  • omit (array of strings, optional): Calendar names or paths to exclude from retrieval.

  • timezone (string, optional): IANA timezone identifier.

4. create_calendar_event

Creates a new event on your calendar.

• Arguments:

  • title (string, required): Title of the event.

  • startDate (string, required): ISO 8601 start date/time (e.g., 2026-06-07T15:00:00).

  • endDate (string, required): ISO 8601 end date/time.

  • description (string, optional): Description or notes.

  • location (string, optional): Location name.

  • url (string, optional): URL linked to the event.

  • timezone (string, optional): IANA timezone identifier. Defaults to America/Chicago. Used to parse inputs if they lack offsets.

5. update_calendar_event

Updates fields on an existing event.

• Arguments:

  • eventId (string, required): The unique event ID (UID).

  • title (string, optional): New title.

  • description (string, optional): New description.

  • location (string, optional): New location.

  • url (string, optional): New URL.

  • startDate (string, optional): New ISO 8601 start date/time.

  • endDate (string, optional): New ISO 8601 end date/time.

  • timezone (string, optional): Target timezone.

6. move_calendar_event

Quickly reschedules an existing event to a new start date/time (optionally keeping the same duration).

• Arguments:

  • eventId (string, required): The unique event ID (UID).

  • startDate (string, required): New ISO 8601 start date/time.

  • endDate (string, optional): New ISO 8601 end date/time. If omitted, the event's original duration is preserved.

  • calendarPath (string, optional): The calendar path where the event is located. If omitted, the server will auto-discover the correct calendar.

  • timezone (string, optional): Target timezone.

🤖 Claude Desktop Integration

To add this server to the Claude Desktop App, edit your configuration file:

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

• Windows: %APPDATA%\Claude\claude_desktop_config.json

Add the following configuration block under mcpServers:

{
  "mcpServers": {
    "apple-calendar": {
      "command": "bun",
      "args": [
        "run",
        "/absolute/path/to/oreo-pudding/src/index.ts"
      ],
      "env": {
        "APP_ID": "your-apple-id@icloud.com",
        "APP_PASS": "xxxx-xxxx-xxxx-xxxx"
      }
    }
  }
}

Make sure to replace /absolute/path/to/oreo-pudding with the actual path to this repository on your machine.

🌐 Poke Integration (poke.com)

This server is designed to work seamlessly with Poke (available at poke.com).

To integrate with Poke:

1. Run the server in SSE mode on a publicly accessible URL or expose it using a port forwarding/tunneling service (e.g., ngrok):

   PORT=3000 bun run index.ts

2. Ensure you have set the BEARER_TOKEN in your .env file to secure the endpoint.

3. In Poke's MCP configuration, add a new SSE connection and supply your server's /sse endpoint URL (e.g., https://your-deployed-domain.com/sse or http://localhost:3000/sse).

4. Provide the BEARER_TOKEN as a Bearer <token> inside Poke's connection Authorization headers.

🧪 Development & Quality Assurance

Linting

We enforce clean styling rules using ESLint with strict JSDoc/TSDoc validation:

# Run lint check
bun run lint

# Auto-fix linting issues
bun run lint:fix

Testing

We use Bun's native test runner. Tests are written under tests/ and cover event serialization, timezone parsing, CalDAV operations, and Mediator routing:

bun test

Extending the Server

When adding new features or tools, please follow the guidelines specified in the Developer & Agent Guidelines to maintain the integrity of our DDD and CQRS architecture.