MCP Reddit Server

Reddit MCP server that provides tools to interact with Reddit.

🚀 Features

• TypeScript: Full type safety with modern TypeScript patterns.
• Reddit Tools: A suite of tools to search posts, get hot/new posts, and view comments.
• HTTP Transport: RESTful API with Express.js for MCP communication.
• Session Management: Stateful connections with proper session handling.
• Configuration Management: Environment-based configuration using .env files.
• Error Handling: Comprehensive error handling and logging.
• Health Checks: Built-in /health monitoring endpoint.
• Docker Support: Production-ready containerization with a Dockerfile.

📋 Prerequisites

• Node.js 20+
• npm

🛠️ Quick Start

# 1. Clone the repository
git clone git@github.com:samwang0723/mcp-reddit.git
cd mcp-reddit

# 2. Install dependencies
npm install

# 3. Create an environment file
# Copy .env.example if it exists, or create a new .env file
# For this project, it's optional, but good practice.
touch .env

# 4. Start the development server
npm run dev

The server will be running at http://localhost:3000 (or the port specified in your .env file).

🔧 Environment Configuration

Create a .env file in the root directory to override default settings:

# Server Configuration
PORT=3000
LOG_LEVEL=info

📜 Development Scripts

• npm run dev: Start the development server with hot reload using tsx.
• npm run build: Compile TypeScript to JavaScript for production.
• npm start: Run the compiled production server.
• npm run test: Run Jest tests.
• npm run lint: Lint the codebase using ESLint.
• npm run lint:fix: Automatically fix linting issues.
• npm run quality: Run type-checking, linting, and formatting checks.

🏗️ Project Structure

mcp-reddit/
├── src/
│   ├── config/           # Configuration management
│   │   └── index.ts
│   ├── services/         # Core application logic (e.g., Reddit API interaction)
│   │   └── reddit.ts
│   ├── utils/            # Utility functions (logging, error handling)
│   │   ├── error.ts
│   │   └── logger.ts
│   └── index.ts          # Main server application and MCP tool registration
├── Dockerfile            # Docker configuration
├── package.json          # Dependencies and scripts
└── tsconfig.json         # TypeScript configuration

🏛️ Architecture

Core Components

1. McpServerApp: The main application class in src/index.ts that configures and runs the MCP server.
2. Express.js: Handles HTTP requests, routing, and middleware.
3. MCP SDK: The @modelcontextprotocol/sdk provides the core functionality for creating MCP servers and tools.
4. Reddit Service: src/services/reddit.ts contains the logic for interacting with the public Reddit JSON API.
5. Session Management: Stateful HTTP-based sessions are managed to handle conversations.

HTTP Endpoints

• GET /health: Health check endpoint.
• POST /mcp: Main MCP endpoint for receiving requests from clients.
• GET /mcp: Endpoint for server-to-client notifications via Server-Sent Events (SSE).
• DELETE /mcp: Endpoint for clients to terminate their session.

🛠️ Available Tools

The server exposes several tools for interacting with Reddit.

reddit-search

Search Reddit posts by a query.

• Parameters:
  • query (string, required): Search query for Reddit posts.
  • limit (number, optional): Number of results to return (default 10).

reddit-hot-all

Get hot posts from all subreddits (r/all).

• Parameters:
  • limit (number, optional): Number of results to return (default 10).

reddit-hot-subreddit

Get hot posts from a specific subreddit.

• Parameters:
  • subreddit (string, required): Subreddit name (without the r/ prefix).
  • limit (number, optional): Number of results to return (default 10).

reddit-new-subreddit

Get the newest posts from a specific subreddit.

• Parameters:
  • subreddit (string, required): Subreddit name (without the r/ prefix).
  • limit (number, optional): Number of results to return (default 10).

reddit-comments

Get the comments for a specific Reddit post.

• Parameters:
  • subreddit (string, required): Subreddit name where the post resides.
  • postId (string, required): The ID of the post.

🐳 Docker Deployment

You can build and run the server in a Docker container.

# 1. Build the Docker image
docker build -t mcp-reddit-server .

# 2. Run the container
# You can pass environment variables directly or use --env-file
docker run -p 3000:3000 -e PORT=3000 mcp-reddit-server

🧪 Testing

Run the test suite using Jest:

# Run all tests
npm test

Create new test files in your project ending with .test.ts to add more tests.