File System Explorer MCP Server

A beginner-friendly MCP (Model Context Protocol) server that demonstrates core MCP concepts through practical file system exploration tools. This project is perfect for learning MCP development while building something immediately useful.

🎯 What You'll Learn

This project teaches you essential MCP concepts:

• Tools: Interactive functions that AI can call (like listing directories or reading files)

• Resources: Static data sources that provide context (like current directory info)

• Prompts: Reusable templates that help users accomplish specific tasks

• Server Architecture: How to structure and implement a proper MCP server

• Error Handling: Best practices for robust MCP server development

🚀 Features

🛠️ Tools

• list_directory - List contents of any directory with file sizes and modification dates

• read_file - Read text files with safety limits and error handling

• get_file_info - Get detailed metadata about files and directories

• search_files - Search for files using wildcard patterns (supports * and ?)

📄 Resources

• Current Directory - Provides information about the working directory

🎨 Prompts

• explore_project - Guided project exploration and analysis

• file_analysis - Analyze files in a directory for patterns and structure

🏗️ Project Structure

MCPServer/
├── src/
│   └── index.ts          # Main server implementation
├── build/                # Compiled JavaScript output
├── .vscode/
│   └── mcp.json         # MCP server configuration
├── .github/
│   └── copilot-instructions.md
├── package.json         # Node.js project configuration
├── tsconfig.json        # TypeScript configuration
└── README.md           # This file

📋 Prerequisites

Before you begin, ensure you have:

• Node.js 18+ installed (download here)

• TypeScript knowledge (basic understanding)

• VS Code (recommended for debugging)

🛠️ Installation & Setup

1. Clone and Install

# Navigate to the project directory
cd MCPServer

# Install dependencies
npm install

# Build the project
npm run build

2. Test Your Server

You can test your server using the MCP Inspector:

# Install and run MCP Inspector
npx @modelcontextprotocol/inspector node build/index.js

This opens a web interface where you can:

• Test all available tools

• View resources

• Try out prompts

• Debug server responses

🎮 How to Use

Basic Usage Examples

Once connected to an MCP client (like Claude Desktop), you can:

Explore a Directory

Can you list the contents of my Desktop folder?

Read a File

Please read the README.md file in my project directory

Search for Files

Find all JavaScript files in my project using the pattern "*.js"

Get File Information

What can you tell me about the package.json file?

Using Prompts

The server includes helpful prompts:

Project Exploration

Use the explore_project prompt with my code directory

File Analysis

Analyze my src directory focusing on TypeScript files

🔧 Connecting to VS Code

1. Make sure you have the MCP extension installed in VS Code

2. The server is already configured in .vscode/mcp.json

3. Restart VS Code to load the configuration

4. You should see the MCP server available in the sidebar

🧪 Development Workflow

Making Changes

1. Edit the source code in src/index.ts

2. Rebuild the project:

   npm run build

3. Test your changes using the MCP Inspector or restart your MCP client

Development Mode

For faster development, use watch mode:

npm run dev

This automatically recompiles when you make changes.

📚 Understanding the Code

Server Initialization

const server = new Server(
  { name: "filesystem-explorer", version: "1.0.0" },
  { capabilities: { tools: {}, resources: {}, prompts: {} } }
);

Adding a Tool

server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;
  
  switch (name) {
    case "your_tool_name": {
      // Your tool logic here
      return {
        content: [{ type: "text", text: "Tool response" }]
      };
    }
  }
});

Security Features

The server includes several security measures:

• Path validation to prevent directory traversal

• File size limits to prevent reading huge files

• Recursion limits in directory search

• Error handling for permission issues

🎓 Learning Exercises

Beginner Exercises

1. Add a new tool that counts lines in a text file

2. Modify the file size limit for reading files

3. Add a new resource that shows system information

Intermediate Exercises

1. Add file writing capabilities (create_file, write_file tools)

2. Implement a simple backup tool that copies files

3. Add support for binary files with proper handling

Advanced Exercises

1. Add file watching capabilities using Node.js file system events

2. Implement a simple git integration (status, log, diff)

3. Add compression/decompression tools for zip files

🐛 Troubleshooting

Common Issues

Server not starting:

• Check that Node.js is installed: node --version

• Ensure dependencies are installed: npm install

• Verify build completed: ls build/ (should contain index.js)

Permission errors:

• Make sure the server has read access to directories

• On Windows, avoid system directories that require admin access

Build errors:

• Clear and reinstall dependencies: rm -rf node_modules && npm install

• Check TypeScript configuration in tsconfig.json

🚀 Next Steps

Once you've mastered this server:

1. Explore other MCP servers in the official repository

2. Build your own specialized server for your domain (database, API, etc.)

3. Contribute to the MCP community with your own implementations

4. Learn about remote MCP servers for cloud-based tools

📖 Additional Resources

• MCP Specification

• MCP TypeScript SDK

• MCP Community Servers

• MCP Inspector Documentation

🤝 Contributing

Want to improve this learning resource?

1. Fork the repository

2. Make your improvements

3. Add tests if applicable

4. Submit a pull request

Ideas for contributions:

• Additional example tools

• Better error messages

• More comprehensive prompts

• Performance improvements

• Additional security features

📝 License

MIT License - feel free to use this code for learning and building your own MCP servers!

🎉 Congratulations!

You've successfully set up your first MCP server! This foundation will help you understand the Model Context Protocol and build more sophisticated integrations. The concepts you've learned here - tools, resources, prompts, and proper error handling - apply to all MCP server development.

Happy coding! 🚀