We believe that tool support is very important for any methodology. In this paper we describe PDT (Prometheus Design Tool) which supports the design of an intelligent agent system using the Prometheus methodology. We describe how PDT supports the various stages of Prometheus through various means such as consistency checking, support for entity propagation, and hierarchical views. We will also describe work that is currently in progress which involves the development of a plug-in for Eclipse with the aim of creating a single integrated development environment which will support the complete development cycle of an agent system from design to deployment.