Safe Local Python Executor/Interpreter

Instructions

This tool allows running simple Python code for calculations and data manipulations.
The execution environment is restricted for security purposes. Make sure you create a single file
that can be executed in one go and it returns a result.

Default allowed imports:
- math
- random 
- datetime
- time
- json
- re
- string
- collections
- itertools
- functools
- operator

Args:
    code: The Python code to execute. Must be valid Python 3 code. The result must be stored in a variable called `result`. E.g.:
    ```python
    import math
    result = math.sqrt(16)
    ```
    
Returns:
    A dictionary with execution results containing:
    - result: The final value or None if no value is returned
    - logs: Any output from print statements

Implementation Reference

• mcp_server.py:30-76 (handler)

  The core handler function for the 'run_python' tool. It is registered via the @mcp.tool() decorator. Executes the provided Python code using a LocalPythonExecutor sandbox and returns the result and logs. The docstring provides the input/output schema details.

  @mcp.tool()
  async def run_python(
      code: str
  ) -> Dict[str, Any]:
      """Execute Python code in a secure sandbox environment.
      
      This tool allows running simple Python code for calculations and data manipulations.
      The execution environment is restricted for security purposes. Make sure you create a single file
      that can be executed in one go and it returns a result.
  
      Default allowed imports:
      - math
      - random 
      - datetime
      - time
      - json
      - re
      - string
      - collections
      - itertools
      - functools
      - operator
      
      Args:
          code: The Python code to execute. Must be valid Python 3 code. The result must be stored in a variable called `result`. E.g.:
          ```python
          import math
          result = math.sqrt(16)
          ```
          
      Returns:
          A dictionary with execution results containing:
          - result: The final value or None if no value is returned
          - logs: Any output from print statements
      """
      logger.info(f"Executing Python code: {code}")
      
      result, logs, _ = executor(code)
  
      response = {
          "result": result,
          "logs": logs
      }
      
      logger.info(f"Execution result: {result}")
      return response

• mcp_server.py:26-27 (helper)

  Initialization of the LocalPythonExecutor used by the run_python tool to safely execute Python code.

  executor = LocalPythonExecutor(additional_authorized_imports=[])
  executor.send_tools({})

• mcp_server.py:24-24 (registration)

  Creation of the FastMCP server instance named 'python-executor', to which tools like run_python are registered.

  mcp = FastMCP("python-executor")