Proton Calendar MCP App

A dark industrial-themed MCP App that displays your Proton Calendar events directly in Claude Desktop.

Features

• Dark industrial UI design
• Monthly calendar view with event indicators
• Upcoming events list
• Click on any day to see its events
• Reads events from Proton Calendar ICS feed

Requirements

• Node.js v20+ (v22 recommended)
• Bun (for building)
• Claude Desktop or compatible MCP host
• Proton Calendar account with a shared calendar link

Installation

# Clone the repository
git clone https://github.com/Rixmerz/proton-calendar-app-mcp.git
cd proton-calendar-app-mcp

# Install dependencies
npm install

# Build
npm run build

Getting Your Proton Calendar URL

1. Go to Proton Calendar
2. Click on Settings (gear icon)
3. Go to Calendars → Select your calendar
4. Scroll to Share via link
5. Create a new link (or copy existing)
6. Copy the ICS URL (looks like https://calendar.proton.me/api/calendar/v1/url/.../calendar.ics?...)

Configuration

Add this to your claude_desktop_config.json:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "proton-calendar": {
      "command": "/path/to/node",
      "args": [
        "/path/to/proton-calendar-app-mcp/dist/index.js",
        "--stdio"
      ],
      "env": {
        "CALENDAR_URL": "https://calendar.proton.me/api/calendar/v1/url/YOUR_CALENDAR_ID/calendar.ics?CacheKey=...&PassphraseKey=..."
      }
    }
  }
}

Finding Your Node Path

# macOS/Linux
which node
# or if using nvm
nvm which 22

# Windows
where node

Usage

After configuring, restart Claude Desktop and say:

"Open my calendar"

or

"Show me my upcoming events"

Claude will display the calendar UI with your Proton Calendar events.

Security Note

Your CALENDAR_URL contains access tokens. Keep your claude_desktop_config.json private and never commit it to version control.

License

MIT