Abstract. The tool USE (UML-based Specification Environment) supports analysts, designers, and developers in executing UML models and checking OCL constraints and thus enables them to employ model-driven techniques for software production. USE has been developed since 1998 at the University of Bremen. This paper will shortly discuss to what extent and how USE relates to the selected questions and topics (like model quality or modelling method) raised for this seminar. 1 Context of USE The Object Constraint Language (OCL) is an important part of the Unified Modeling Language (UML) [OMG05,RJB05]. OCL can be used within UML for various tasks: