We demonstrate an intelligent personal assistant agent that has been developed to aid a busy knowledge worker in managing time commitments and performing tasks. The PExA agent draws on a diverse set of AI technologies that are linked within the SPARK BDI agent framework. We focus on our agent's ability to provide assistance within the context of current user activities, based on its recognition of user workflows and their progress, and on its contextsensitive proactive suggestions. We have instrumented a common suite of desktop applications so that, endowed with a sophisticated workflow tracker, PExA has the ability to pervasively monitor the user's desktop activities. PExA follows and responds to the user's progress on shared tasks, and is highly user-centric in its support for user needs and its adaptivity to user working style and preferences. Categories and Subject Descriptors I.2.11 [ARTIFICIAL INTELLIGENCE]: Distributed Artificial Intelligence--Intelligent agents;...