An object-oriented software design is often modelled as a collection of UML diagrams. There is an inherent need to preserve the consistency between these diagrams. Moreover, through evolution these diagrams get modified and can become inconsistent. To be able to preserve their consistency the formalism of description logics is used. Loom, a second generation reasoning tool, and RACER, a state-of-the-art reasoning tool, are used as particular description logic reasoning systems. Based on our experience with these tools, we argue that state-of-the-art description logic tools must offer a more extensive query language.