Safe Local Python Executor MCP server

Safe Local Python Executor is an MCP server that wraps Hugging Face's LocalPythonExecutor, providing a secure way to run Python code generated by LLMs locally. It offers basic isolation and security without requiring Docker or VMs, making it an excellent tool for adding Code Interpreter functionality to Claude Desktop or other MCP-compatible clients.

Features and Security

The Safe Local Python Executor provides:

• A run_python tool accessible via MCP
• Safer execution compared to direct Python eval()
• Execution in an isolated Python virtual environment via uv
• No file I/O operations allowed
• A restricted list of permitted imports:
  • collections
  • datetime
  • itertools
  • math
  • queue
  • random
  • re
  • stat
  • statistics
  • time
  • unicodedata

This approach balances convenience with security, offering a middle ground between direct Python execution (insecure) and Docker/VM isolation (complex setup).

Installation

Via Smithery

The easiest way to install is using Smithery:

npx -y @smithery/cli install @maxim-saplin/mcp_safe_local_python_executor --client claude

Manual Installation

1. Install uv first:

   # On macOS
   brew install uv
   
   # For other platforms, follow the official documentation
   # at https://docs.astral.sh/uv/getting-started/installation/
   

2. Clone the repository and navigate to it:

   git clone [repository-url]
   cd mcp_safe_local_python_executor
   

3. Start the server:

   uv run mcp_server.py
   

   The command will automatically create a virtual environment and install all dependencies.

Configuring Claude Desktop

1. Make sure Claude Desktop is installed (available from claude.ai)

2. Edit your Claude Desktop configuration file:

   • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
   • Windows: %APPDATA%\Claude\claude_desktop_config.json
   • Or open Claude Desktop → Settings → Developer → click "Edit Config" button

3. Add the following configuration:

   {
       "mcpServers": {
           "safe-local-python-executor": {
               "command": "uv",
               "args": [
                   "--directory", 
                   "/path/to/mcp_local_python_executor/",
                   "run",
                   "mcp_server.py"
               ]
           }
       }
   }
   

4. Restart Claude Desktop

5. The Python executor tool will now be available in Claude (you'll see a hammer icon in the message input field)

Example Usage

Once configured, you can use prompts like:

• "Calculate the factorial of 5 using Python"
• "Create a list of prime numbers up to 100"
• "Solve this equation (use Python): x^2 + 5x + 6 = 0"

The tool will execute the Python code in a secure environment and return the results directly in your conversation with Claude.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "safe-local-python-executor" '{"command":"uv","args":["--directory","/path/to/mcp_local_python_executor/","run","mcp_server.py"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "safe-local-python-executor": {
            "command": "uv",
            "args": [
                "--directory",
                "/path/to/mcp_local_python_executor/",
                "run",
                "mcp_server.py"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "safe-local-python-executor": {
            "command": "uv",
            "args": [
                "--directory",
                "/path/to/mcp_local_python_executor/",
                "run",
                "mcp_server.py"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect