STeLA MCP

A Python implementation of a Model Context Protocol server that provides secure access to local system operations via a standardized API interface.

STeLA (Simple Terminal Language Assistant) MCP is a lightweight server that provides secure access to local machine commands and file operations via a standardized API interface. It acts as a bridge between applications and your local system, implementing the Model Context Protocol (MCP) architecture.

Overview

STeLA MCP implements the Model Context Protocol (MCP) architecture to provide a secure, standardized way for applications to execute commands and perform file operations on a local machine. It serves as an intermediary layer that accepts requests through a well-defined API, executes operations in a controlled environment, and returns formatted results.

Features

• Command Execution: Run shell commands on the local system with proper error handling
• File Operations: Read, write, and manage files on the local system
• Directory Visualization: Generate recursive tree views of file systems
• Working Directory Support: Execute commands in specific directories
• Robust Error Handling: Detailed error messages and validation
• Comprehensive Output: Capture and return both stdout and stderr
• Simple Integration: Standard I/O interface for easy integration with various clients

Installation

Installing via Smithery

To install STeLA for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @Sachin-Bhat/stela-mcp --client claude

Prerequisites

• Python 3.10 - 3.12
• pip or uv package manager

Installation Steps

1. Clone the repository:

git clone <repository-url>
cd stela-mcp

2. Create and activate a virtual environment:

python -m venv .venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

3. Install dependencies:

pip install -e .

Creating a Binary Distribution

To create a self-contained binary:

1. Install PyInstaller:

pip install pyinstaller

2. Create the binary:

pyinstaller --onefile src/stella_mcp//server.py --name stela-mcp

The binary will be created in the dist directory.

Project Structure

stela-mcp/
├── src/
│   ├── stela_mcp/
│   │   ├── __init__.py
│   │   ├── shell.py        # Shell command execution
│   │   └── filesystem.py   # File system operations
│   └── server.py           # Main server implementation
├── pyproject.toml          # Project configuration
└── README.md

Usage

Starting the Server

Run the server using:

uv run python -m src.stella_mcp.server

The server will start and listen for connections through standard I/O.

Using with Claude Desktop

To use STeLA MCP with Claude Desktop:

1. Option 1: Using Python directly

   • Start the server using:

     uv run python -m src.stela_mcp.server
     

   • In Claude Desktop:
     • Go to Settings
     • Under "Tools", click "Add Tool"
     • Select "MCP Server"
     • Enter the following configuration:
       • Name: STeLA MCP
       • Path: The absolute path to your Python executable (e.g., /home/username/.venv/bin/python)
       • Arguments: -m src.stela_mcp.server
       • Working Directory: The path to your STeLA MCP project directory

2. Option 2: Using the binary

   • Copy the binary from dist/stela-mcp to a location in your PATH
   • In Claude Desktop:
     • Go to Settings
     • Under "Tools", click "Add Tool"
     • Select "MCP Server"
     • Enter the following configuration:
       • Name: STeLA MCP
       • Path: The absolute path to the binary (e.g., /usr/local/bin/stela-mcp)
       • Arguments: (leave empty)
       • Working Directory: (leave empty)

3. Once configured, you can use STeLA MCP tools in your conversations with Claude. For example:

   • "Show me the contents of my home directory"
   • "Create a new file called 'test.txt' with some content"
   • "Run the command 'ls -la' in my current directory"

4. Claude will automatically use the appropriate tools based on your requests and display the results in the conversation.

Available Tools

Command Tools

execute_command

Executes shell commands on the local system.

Parameters:

• command (string, required): The shell command to execute
• working_dir (string, optional): Directory where the command should be executed

Returns:

• On success: Command output (stdout)
• On failure: Error message and any command output (stderr)

change_directory

Changes the current working directory.

Parameters:

• path (string, required): Path to change to

Returns:

• On success: Success message with new path
• On failure: Error message

File System Tools

read_file

Reads the contents of a file.

Parameters:

• path (string, required): Path to the file to read

Returns:

• On success: File contents
• On failure: Error message

write_file

Writes content to a file.

Parameters:

• path (string, required): Path where the file will be written
• content (string, required): Content to write to the file

Returns:

• On success: Success message
• On failure: Error message

list_directory

Lists contents of a directory.

Parameters:

• path (string, required): Path for the directory to list

Returns:

• On success: List of files and directories
• On failure: Error message

create_directory

Creates a new directory.

Parameters:

• path (string, required): Path for the directory to create

Returns:

• On success: Success message
• On failure: Error message

move_file

Moves or renames files and directories.

Parameters:

• source (string, required): Source path of the file or directory to move
• destination (string, required): Destination path where the file or directory will be moved to

Returns:

• On success: Success message
• On failure: Error message

search_files

Searches for files matching a pattern.

Parameters:

• path (string, required): Starting path for the search
• pattern (string, required): Search pattern to match file and directory names

Returns:

• On success: List of matching files
• On failure: Error message

directory_tree

Generates a recursive tree view of files and directories.

Parameters:

• path (string, required): Path for the directory to generate tree from

Returns:

• On success: JSON structure representing the directory tree
• On failure: Error message

Security Considerations

STeLA MCP provides direct access to execute commands and file operations on the local system. Consider the following security practices:

• Run with appropriate permissions (avoid running as root/administrator)
• Use in trusted environments only
• Consider implementing additional authorization mechanisms for production use
• Be cautious about which directories you allow command execution and file operations in
• Implement path validation to prevent unauthorized access to system files

Platform-Specific Security Notes

Linux/macOS

• Run with a dedicated user with limited permissions
• Consider using a chroot environment to restrict file system access
• Use chmod to restrict executable permissions

Windows

• Run as a standard user, not an administrator
• Consider using Windows Security features to restrict access
• Use folder/file permissions to limit access to sensitive directories

Development

Adding New Tools

To extend STeLA MCP with additional functionality, follow this pattern:

1. Add a new method to the appropriate class in shell.py or filesystem.py
2. Register the tool in server.py using the @server.call_tool() decorator
3. Implement the tool handler with proper error handling and return types

Example:

@server.call_tool()
async def my_tool(request: Request[RequestParams, str], arguments: Dict[str, Any]) -> Dict[str, Any]:
    """Description of the tool."""
    try:
        # Tool implementation
        result = await do_something(arguments)
        return {"success": True, "result": result}
    except Exception as e:
        return {"error": str(e)}

License

Apache-2.0 License

Acknowledgements

• Built with the MCP Python SDK