In the research domain agent-based systems are widely used for mobile and distributed information systems. Their underlying paradigm provides excellent mechanisms to isolate tasks in independent modules that can be re-used and combined in multiple ways. In order to facilitate the communication between such agents a common domain-knowledge needs to be collected and stored in an ontology. This paper introduces an XML-based ontology representation for mobile multi-agent systems. A uniform XSLTbased mechanism that allows for transforming agent communication into a format readable by human users is presented. We show how the resulting combination of domain representation and presentation allows highly flexible agent systems where users interface agents can feed information from any service agent to the user or vice versa and how this approach can be easily extended to take user- or context-adaptive presentation strategies into account. Additionally, we describe how these mechanisms are inte...