GEMS EMF Intelligence is a framework designed to help you reason about your EMF models. The framework provides a knowledge base that you can assert EMF modeling elements into. Once modeling elements are asserted into the knowledge base, you can add constraints to relationships between model elements. Finally, you can use GEMS EMF Intelligence to derive valid endpoints (other objects in the knowledge base) for relationships (such as EReferences) of a modeling element. GEMS EMF Intelligence supports constraints written in OCL, Prolog, Groovy, and BeanShell. Multiple constraint languages can be mixed in a single knowledge base.