Proton Calendar MCP App

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

Dark Theme Node

Screenshot

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

Go to Proton Calendar
Click on Settings (gear icon)
Go to Calendars → Select your calendar
Scroll to Share via link
Create a new link (or copy existing)
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.jsonWindows: %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"

"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

Proton Calendar MCP App