Liturgical Calendar MCP Server (TypeScript)

A Model Context Protocol (MCP) server written in TypeScript that provides access to the Roman Catholic Liturgical Calendar API.

Note: Looking for the Python version? See liturgical-calendar-mcp (Python)

Why TypeScript?

This is a TypeScript rewrite of the Python version with these advantages:

• Native MCP SDK: First-class TypeScript support from the official MCP SDK
• Smaller container: Node.js Alpine image is ~50MB vs Python ~100MB+
• Native async/await: Clean promise-based HTTP requests
• Type safety: Full TypeScript types for better IDE support and error catching
• Simple dependencies: Only needs @modelcontextprotocol/sdk (built-in fetch)

Features

• get_general_calendar - General Roman Calendar for any year (1970-9999)
• get_national_calendar - National calendars (IT, US, NL, VA, CA, etc.)
• get_diocesan_calendar - Diocesan calendars with local celebrations
• list_available_calendars - Discover all available calendars
• get_liturgical_events - All possible liturgical events

Architecture

This server follows a clean modular architecture with separation of concerns:

For detailed architecture documentation, see ARCHITECTURE.md.

Prerequisites

• Node.js 18+ (20+ recommended)
• Docker Desktop with MCP Toolkit (for Docker deployment)
• No authentication required

Installation

Option 1: Local Development

# Clone the repository
git clone https://github.com/CatholicOS/liturgical-calendar-mcp.git
cd liturgical-calendar-mcp

# Install dependencies
npm install

# Build TypeScript
npm run build

# Run the server
npm start

Option 2: Docker

# Build the Docker image
docker build -f Dockerfile.ts -t liturgical-calendar-mcp-ts:latest .

# Run with Docker
docker run -i liturgical-calendar-mcp-ts:latest

Configuration for MCP Clients

Claude Desktop Configuration

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "liturgical-calendar": {
      "command": "node",
      "args": ["/absolute/path/to/liturgical-calendar-mcp/build/index.js"]
    }
  }
}

Docker MCP Toolkit

Edit ~/.docker/mcp/catalogs/docker-mcp.yaml:

  litcal-ts:
    description: "Access Roman Catholic Liturgical Calendar data (TypeScript)"
    title: "Liturgical Calendar (TS)"
    type: server
    dateAdded: "2025-10-22T00:00:00Z"
    image: liturgical-calendar-mcp-ts:latest
    tools:
      - name: get_general_calendar
      - name: get_national_calendar
      - name: get_diocesan_calendar
      - name: list_available_calendars
      - name: get_liturgical_events
    metadata:
      category: integration
      tags:
        - catholic
        - liturgy
        - calendar
      license: MIT

Development

# Watch mode for development
npm run watch

# Build for production
npm run build

# Run tests (if added)
npm test

Project Structure

.
├── src/
│   └── index.ts          # Main MCP server implementation
├── build/                # Compiled JavaScript (generated)
├── package.json          # Dependencies and scripts
├── tsconfig.json         # TypeScript configuration
├── Dockerfile.ts         # Docker build file
└── README-typescript.md  # This file

Comparison with Python Version

Feature	Python	TypeScript
Runtime size	~100MB	~50MB
Dependencies	2 (mcp, httpx)	1 (@modelcontextprotocol/sdk)
HTTP client	httpx (external)	fetch (built-in)
Type safety	Optional (mypy)	Built-in
Async model	asyncio	Promises/async-await
MCP SDK	FastMCP wrapper	Official SDK

API Reference

get_general_calendar

{
  year?: string,    // 1970-9999 (default: current year)
  locale?: string   // en, es, it, fr, etc. (default: en)
}

get_national_calendar

{
  nation: string,   // IT, US, NL, VA, CA (required)
  year?: string,    // 1970-9999 (default: current year)
  locale?: string   // en, es, it, fr, etc. (default: en)
}

get_diocesan_calendar

{
  diocese: string,  // ROME-IT, BOSTON-US (required)
  year?: string,    // 1970-9999 (default: current year)
  locale?: string   // en, es, it, fr, etc. (default: en)
}

list_available_calendars

{
  // No parameters required
}

Returns all available national and diocesan calendars with their locales.

get_liturgical_events

{
  calendarType?: string,  // "general", "national", or "diocesan" (default: general)
  nation?: string,        // Required if calendarType is "national"
  diocese?: string        // Required if calendarType is "diocesan"
}

Retrieves all possible liturgical events for a calendar type.

License

MIT

Credits

• Liturgical Calendar API by Rev. John R. D'Orazio
• MCP Protocol by Anthropic