Slim MCP

Instructions

Implementation Reference

• src/claude_tools/calculator.py:3-25 (handler)

  The handler function for the 'calculate' tool. It safely evaluates mathematical expressions using a restricted eval environment with math functions.

  def calculate(expression: str) -> str:
      """Calculate the result of a mathematical expression.
      Args:
          expression: A mathematical expression as a string (e.g. "2 + 2", "sin(30)")
      """
      try:
          # Replace common math functions with their python equivalents
          expression = expression.replace("^", "**")
          
          # Create a safe namespace with only math functions
          safe_dict = {
              'abs': abs, 'round': round,
              'sin': math.sin, 'cos': math.cos, 'tan': math.tan,
              'asin': math.asin, 'acos': math.acos, 'atan': math.atan,
              'sqrt': math.sqrt, 'log': math.log, 'log10': math.log10,
              'pi': math.pi, 'e': math.e
          }
          
          # Evaluate the expression in the safe namespace
          result = eval(expression, {"__builtins__": {}}, safe_dict)
          return f"Result: {result}"
      except Exception as e:
          return f"Error: {str(e)}"

• src/claude_tools/calculator.py:27-30 (registration)

  Registers the 'calculate' tool using mcp.tool() decorator.

  def register_calculator_tools(mcp):
      """Register all calculator tools with the MCP server."""
      mcp.tool()(calculate)

• src/claude_tools/calculator.py:3-7 (schema)

  Type hints and docstring defining the input schema for the 'calculate' tool.

  def calculate(expression: str) -> str:
      """Calculate the result of a mathematical expression.
      Args:
          expression: A mathematical expression as a string (e.g. "2 + 2", "sin(30)")
      """