Unit Converter MCP

Instructions

Implementation Reference

• src/unit_converter_mcp/server.py:62-76 (handler)

  MCP tool handler registered with @app.tool() that executes the temperature conversion by calling the core tool function and formats the response dictionary.

  @app.tool()
  def convert_temperature(
      value: Annotated[float, Field(description="Temperature value to convert")],
      from_unit: Annotated[TEMPERATURE_UNIT, Field(description="Source unit")],
      to_unit: Annotated[TEMPERATURE_UNIT, Field(description="Target unit")],
  ) -> dict:
      """Convert temperature between units."""
      converted_value = convert_temperature_tool(value, from_unit, to_unit)
      return {
          "original_value": value,
          "original_unit": from_unit,
          "converted_value": converted_value,
          "converted_unit": to_unit,
          "conversion_type": "temperature",
      }

• src/unit_converter_mcp/tools/temperature.py:8-8 (schema)

  Literal type definition for supported temperature units, used in the tool schema for input validation.

  TEMPERATURE_UNIT = Literal["celsius", "fahrenheit", "kelvin"]

• src/unit_converter_mcp/tools/temperature.py:34-59 (helper)

  Core helper function implementing the temperature unit conversion logic via intermediate conversion to Celsius.

  def convert_temperature_tool(
      value: float,
      from_unit: TEMPERATURE_UNIT,
      to_unit: TEMPERATURE_UNIT,
  ) -> float:
      """Convert temperature between units."""
  
      # Dictionary mapping units to their conversion functions to Celsius
      to_celsius: dict[TEMPERATURE_UNIT, Callable[[float], float]] = {
          "fahrenheit": _fahrenheit_to_celsius,
          "kelvin": _kelvin_to_celsius,
          "celsius": lambda x: x,
      }
  
      # Dictionary mapping units to their conversion functions from Celsius
      from_celsius: dict[TEMPERATURE_UNIT, Callable[[float], float]] = {
          "fahrenheit": _celsius_to_fahrenheit,
          "kelvin": _celsius_to_kelvin,
          "celsius": lambda x: x,
      }
  
      # Convert to Celsius first
      celsius = to_celsius[from_unit](value)
  
      # Convert from Celsius to target unit
      return from_celsius[to_unit](celsius)