Mutmut MCP

Instructions

Implementation Reference

• mutmut_mcp.py:65-90 (handler)

  The handler function 'run_mutmut' which executes the mutation testing command.

  def run_mutmut(target: str, options: str = "", venv_path: Optional[str] = None) -> str:
      """
      Run a full mutation testing session with mutmut on the specified target.
  
      This tool initiates mutation testing on the given module or package. You can provide
      additional mutmut options as needed. The output includes a summary of mutations tested,
      including counts of killed, survived, and timed-out mutations. If a virtual environment
      path is provided, mutmut will be run using the binaries from that environment to ensure
      compatibility with project-specific dependencies.
  
      Args:
          target (str): The module or package to run mutation testing on.
          options (str): Additional command-line options for mutmut (e.g., '--use-coverage'). Defaults to empty.
          venv_path (Optional[str]): Path to the project's virtual environment to use for running mutmut. Defaults to None.
  
      Returns:
          str: Summary of the mutation testing run, or error message if the run fails.
      """
      if venv_path:
          mutmut_path = _get_mutmut_path(venv_path)
          if not os.path.exists(mutmut_path):
              return f"Error: mutmut not found in the specified venv at {mutmut_path}. Please ensure mutmut is installed in the venv."
          command = [mutmut_path, "run", target] + options.split()
      else:
          command = ["mutmut", "run", target] + options.split()
      return _run_command(command)

• mutmut_mcp.py:182-182 (registration)

  Registration of the 'run_mutmut' tool with the MCP server.

  mcp.tool()(run_mutmut)