We present a software tool for creating an optimal classhierarchy from the use-relationship among data-items and functions based on the method in Kundu and Gwee [3]. The tool determines the classes and their inheritance relationship, including the assignment of variables and functions to the various classes and their appropriate access levels (private, etc.). We define a class-design language for modeling the classes and the userelationship and a script language for manipulating the classes. The input to the tool and its operations are based on the constructs of these languages. We illustrate the tool with a small non-trivial class design problem.