Expr Lang

🚀 MCP Expression Language

A powerful expression evaluation tool for Claude Desktop, integrated via the Model Context Protocol (MCP).

🚀 Quick Start

MCP Expr-Lang seamlessly integrates Claude AI with the powerful expr-lang expression evaluation engine. This tool enables you to perform complex data operations, calculations, and transformations directly within Claude conversations.

With MCP Expr-Lang, you can:

• Evaluate mathematical expressions
• Transform and filter arrays and objects
• Sort complex data display structures
• Perform string operations
• Use conditional logic
• And many more!

📦 Installation

Install via Smithery

To automatically install MCP Expr-Lang for Claude Desktop via Smithery:

npx -y @smithery/cli install @ivan-saorin/mcp-expr-lang --client claude

Prerequisites

• Go 1.18 or higher
• Claude Desktop application
• Git

Step 1: Clone the repository

git clone https://github.com/ivan-saorin/mcp-expr-lang.git
cd mcp-expr-lang

Step 2: Install dependencies

go mod download

Step 3: Build the application

For Windows

go build -o bin/server.exe

For macOS/Linux

go build -o bin/server
chmod +x bin/server

Step 4: Configure Claude Desktop

1. Open the Claude Desktop application
2. Go to settings
3. Navigate to the "Advanced" section
4. Add the following configuration to your config.json file:

For Windows

{
  "mcpServers": {
    "eval": {
      "command": "C:\\path\\to\\mcp-expr-lang\\bin\\server.exe"
    }
  }
}

For macOS/Linux

{
  "mcpServers": {
    "eval": {
      "command": "/path/to/mcp-expr-lang/bin/server"
    }
  }
}

5. Save the configuration and restart the application

💻 Usage Examples

Basic Usage

In your Claude script, use the following:

{
  "operations": {
    "add": {
      "a": 10,
      "b": 20
    }
  }
}

Claude will return the result:

{
  "result": 30
}

Advanced Usage

In your Claude script, use the following:

{
  "operations": {
    "filter": {
      "array": [1, 2, 3, 4],
      "condition": "> 2"
    }
  }
}

Claude will return the result:

{
  "result": [3, 4]
}

✨ Features

• Support for complex mathematical operations
• Flexible array and object operations
• Powerful conditional logic
• Secure and efficient execution environment
• Easy to extend and customize

🛠️ Troubleshooting

Problem 1: Unable to start the service

Check the following:

1. Ensure the correct Go version (1.18 or higher)
2. Ensure dependencies are correctly installed
3. Check if the config.json file is correctly configured

🤝 Contributing

Any contributions are welcome! If you want to improve MCP Expr-Lang, follow these steps:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a pull request

📄 License

This project is licensed under the MIT License. See the LICENSE file for details.

🙏 Acknowledgments

• expr-lang for providing a powerful expression evaluation engine
• mcp-golang for the implementation of the Model Context Protocol
• Claude AI for providing the artificial intelligence assistant platform

Crafted with ❤️ by Ivan Saorin