# MCP Command Server Command Line Icon

**Secure JSON-RPC API for Remote Command Execution**

MCP Command Server provides a secure, containerized interface for remote command execution with built-in pattern-based security validation, comprehensive API documentation, and enterprise-ready deployment configurations.

## 📋 Table of Contents - [🔍 Overview](#-overview) - [✨ Features](#-features) - [🏗️ Architecture](#-architecture) - [🚀 Installation](#-installation) - [🧰 Usage](#-usage) - [📚 API Documentation](#-api-documentation) - [🔒 Security](#-security) - [💻 Development](#-development) - [🧪 Testing](#-testing) - [👥 Contributing](#-contributing) - [📄 License](#-license) ## 🔍 Overview MCP Command Server provides a JSON-RPC 2.0 compliant API for executing shell commands on the server. It's designed with security in mind, featuring command pattern exclusion to prevent potentially harmful operations. The server is fully containerized with Docker and includes comprehensive API documentation accessible directly through the API. ## ✨ Features - **JSON-RPC 2.0 API**: Standardized interface for command execution - **Command Security**: Pattern-based command filtering to block potentially harmful operations - **Self-Documenting**: Built-in `/context` endpoint serving markdown documentation - **Containerized**: Ready-to-use Docker configuration - **Production-Ready**: Security-focused design with non-root execution - **Developer-Friendly**: Complete Postman collection for testing ## 🏗️ Architecture ```mermaid flowchart TB Client[Client] -->|HTTP POST JSON-RPC| Server[MCP Command Server] Client -->|HTTP GET| Context["/context" Documentation] subgraph Server["MCP Command Server (Port 3030)"] API[JSON-RPC API] --> Validator[Command Validator] Validator -->|if safe| Executor[Command Executor] Validator -->|if unsafe| Reject[Reject Command] Context end Validator --> ExcludeYAML[exclude.yaml] Context --> ContextMD[.context] Executor -->|execute| Shell[Shell] Shell --> Results[Command Results] Results --> API classDef container fill:#326ce5,stroke:#fff,stroke-width:1px,color:#fff; classDef component fill:#fff,stroke:#000,stroke-width:1px,color:#000; classDef config fill:#f9f,stroke:#333,stroke-width:1px,color:#333; class Server,Shell container; class API,Validator,Executor,Context,Reject,Results component; class ExcludeYAML,ContextMD config; ``` ### Component Flow ```mermaid sequenceDiagram participant Client participant Server as MCP Command Server participant Validator participant Executor participant Shell Client->>Server: POST / {JSON-RPC Request} Server->>Validator: Validate command alt Command matches exclusion pattern Validator->>Server: Reject (Security violation) Server->>Client: Error response else Command is safe Validator->>Executor: Execute command Executor->>Shell: Run shell command Shell->>Executor: Command output Executor->>Server: Process results Server->>Client: JSON-RPC Response end Client->>Server: GET /context Server->>Client: Markdown documentation ``` ## 🚀 Installation ### Prerequisites - Docker and Docker Compose - Git (for cloning the repository) ### Using Docker (Recommended) 1. Clone the repository: ```bash git clone https://github.com/yourusername/mcp_command_server.git cd mcp_command_server ``` 2. Start the server using Docker Compose: ```bash docker-compose up -d ``` 3. The server will be available at `http://localhost:3030` ### Building from Source 1. Ensure you have Rust installed (1.74+ recommended): ```bash curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh ``` 2. Clone and build the project: ```bash git clone https://github.com/yourusername/mcp_command_server.git cd mcp_command_server cargo build --release ``` 3. Run the server: ```bash ./target/release/mcp_command_server ``` ## 🧰 Usage ### Basic Commands Execute a simple command: ```bash curl -X POST -H "Content-Type: application/json" -d '{ "jsonrpc": "2.0", "id": 1, "method": "command/get", "params": { "command": "echo \"Hello World\"" } }' http://localhost:3030/ ``` Response: ```json { "jsonrpc": "2.0", "id": 1, "result": { "stdout": "Hello World\n" } } ``` ### Access API Documentation Get the API documentation in markdown format: ```bash curl http://localhost:3030/context ``` ## 📚 API Documentation The MCP Command Server provides comprehensive documentation via the `/context` endpoint. This documentation is served as markdown and includes: - API overview - Available methods - Request/response formats - Error codes - Usage examples - Security considerations ### JSON-RPC Specification The API follows the JSON-RPC 2.0 specification: - **Endpoint**: `http://localhost:3030/` - **Method**: POST - **Content-Type**: application/json - **Body Format**: ```json { "jsonrpc": "2.0", "id": "", "method": "command/get", "params": { "command": "" } } ``` ### Available Methods | Method | Description | Parameters | |--------|-------------|------------| | `command/get` | Executes a shell command | `command`: string | ### Response Format **Success Response:** ```json { "jsonrpc": "2.0", "id": "", "result": { "stdout": "" } } ``` **Error Response:** ```json { "jsonrpc": "2.0", "id": "", "error": { "code": "", "message": "" } } ``` ### Error Codes | Code | Message | Description | |------|---------|-------------| | -32602 | Missing 'command' parameter | The required 'command' parameter was not provided | | -32000 | Command execution error | The command could not be executed or was rejected | | -32601 | Method not found | The specified method does not exist | ## 🔒 Security The MCP Command Server implements several security measures: ### Command Exclusion System The server uses a pattern-based exclusion system to prevent potentially harmful commands from being executed. This is configured through the `exclude.yaml` file, which contains: - Plain text patterns (e.g., `rm -rf`, `sudo`, `apt`) - Regular expression patterns (e.g., `regex:.*\.\.\/.*`) - Options for case sensitivity and matching behavior ```mermaid flowchart LR Command[Command Input] --> Validator[Command Validator] ExcludeYAML[exclude.yaml] --> Validator Validator --> Check{Safe?} Check -->|Yes| Execute[Execute Command] Check -->|No| Reject[Reject with Error] subgraph Patterns Plain[Plain Text Patterns] Regex[Regular Expression Patterns] end ExcludeYAML --> Patterns ``` ### Blocked Command Categories The command exclusion system blocks several categories of potentially harmful commands: - System modification (`apt`, `yum`, etc.) - File deletion/modification (`rm -rf`, etc.) - System control (`shutdown`, `reboot`, etc.) - User/permission changes (`chmod`, `sudo`, etc.) - Network operations (`wget`, `curl`, etc.) - Command chaining to bypass filters (`&&`, `|`, etc.) - Script execution (`bash`, `python`, etc.) - Filesystem traversal (`../`, etc.) ### Docker Security The server runs as a non-root user within the Docker container to limit potential damage from security breaches. ## 💻 Development ### Project Structure ``` mcp_command_server/ ├── .context # API documentation markdown ├── Cargo.toml # Rust dependencies ├── Dockerfile # Multi-stage Docker build ├── exclude.yaml # Command exclusion patterns ├── docker-compose.yml # Docker Compose configuration ├── src/ │ ├── main.rs # Main server code │ ├── command.rs # Command execution logic │ ├── rpc.rs # JSON-RPC handling │ └── validator.rs # Command validation logic └── docs/ ├── README.md # Documentation for the Postman collection └── mcp_command_server.postman_collection.json # Postman collection ``` ### Dependencies - **Rust**: Primary programming language - **tokio**: Async runtime for Rust - **warp**: Web server framework - **serde** & **serde_json**: Serialization/deserialization - **serde_yaml**: YAML parsing for exclusion patterns - **regex**: Regular expression support for command validation ## 🧪 Testing ### Using the Postman Collection A comprehensive Postman collection is included in the `docs/` directory for testing the API: 1. Import `docs/mcp_command_server.postman_collection.json` into Postman 2. Run individual requests or the entire collection 3. The collection includes tests for: - Basic commands - Error handling - Command execution - File operations - Security validation ### Manual Testing Test basic functionality with curl: ```bash # Test the context endpoint curl http://localhost:3030/context # Execute a simple command curl -X POST -H "Content-Type: application/json" -d '{ "jsonrpc": "2.0", "id": 1, "method": "command/get", "params": { "command": "echo \"Hello World\"" } }' http://localhost:3030/ ``` ## 👥 Contributing Contributions are welcome! Please feel free to submit a Pull Request. 1. Fork the repository 2. Create your 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. --- Built with ❤️ using Rust and Docker.