Lemonade Stand MCP Server

🚀 Lemonade Stand MCP Server

A simple and runnable example MCP server that allows you to play the classic Lemonade Stand game through Claude Desktop.

🚀 Quick Start

To quickly start the project, follow these steps:

1. Clone the repository:

   git clone https://github.com/yourusername/Lemonade-Stand-MCP-Server.git
   cd Lemonade-Stand-MCP-Server
   

2. Install dependencies:

   npm install
   

3. Configure Claude Desktop:

   • Open the config.json file.
   • Add the following content to the tools section:

     {
       "tools": [
         {
           "id": "lemonade-stand",
           "name": "Lemonade Stand Game",
           "description": "An MCP server for playing the Lemonade Stand game.",
           "type": "custom",
           "url": "http://localhost:3000"
         }
       ]
     }
     

   • Restart Claude Desktop.

✨ Features

• 🌤️ A dynamic weather system that affects sales.
• 💰 A business simulation including supply and demand.
• 📊 Strategic pricing and inventory management.
• 🏁 A 14 - day game cycle with profit tracking.
• 🎮 Fully playable through Claude Desktop.

📦 Installation

Prerequisites

• Node.js (Recommended v20.11.1 or higher)
• Claude Desktop

💻 Usage Examples

Play the Game

To start playing the game, follow these steps:

1. Start the server:

   node server.js
   

2. Call the tool lemonade-stand.start_game() in Claude to start a new game.

3. Use other tools to manage your lemonade stand, for example:

   • lemonade-stand.get_status(): Get the current game status.
   • lemonade-stand.buy Supplies({ cups: 10, lemon: 5 }): Buy supplies.
   • lemonade-stand.sell Lemonade({ price: 2.5, quantity: 20 }): Sell lemonade.

📚 Documentation

What is MCP?

The Model Context Protocol (MCP) is an open standard that enables AI models (such as Claude) to interact with external data sources and tools. This server demonstrates how MCP works by implementing the classic Lemonade Stand game as a set of tools that Claude can use.

Game Mechanics

This game simulates a simple business scenario where players need to manage resources and pricing strategies to maximize profits. Here are the key mechanisms:

• Weather System: Affects the sales volume of the lemonade stand. Sales are high on sunny days and low on rainy days.
• Supply Chain: Players can buy cups, lemons, and other necessities.
• Pricing Strategy: Players can adjust prices to influence sales volume and profits.

Configuration Examples

For WSL Users

If you are using the Windows Subsystem for Linux, change the path to:

%UserProfile%/Documents/Claude/config.json

Using npx

You can directly run:

npx server.js

Troubleshooting

• Can't find the hammer icon: Check if the configuration file is correct and ensure that the server is running.
• Unable to connect to the server: Make sure the server is running and the address is correct.

Development

To modify the server code, follow these steps:

1. Modify the server.js file.
2. Restart the server:

   node server.js
   

3. Test the changes in Claude.

Project Structure

Lemonade-Stand-MCP-Server/
├── server.js              # Main MCP server implementation
├── package.json           # Node.js dependencies
└── README.md             # This file

How It Works

This MCP server implements a simple game loop:

1. The server maintains the game state in memory.
2. Each tool represents a game action (buying, selling, etc.).
3. When Claude calls a tool, the server updates the game state.
4. The results are returned to Claude in JSON format.
5. Claude analyzes the results and decides the next action.

This demonstrates how to use MCP to create interactive experiences where an AI model can maintain state, make decisions, and interact with complex systems.

📄 License

If you have any suggestions for improvement or find any errors, please feel free to open an issue or submit a pull request.