The goal of this ongoing project is to develop an open agent architecture and accompanying user interface for networked desktop and handheld machines. The system we are building should support distributed execution of a user's requests, interoperabilityofmultiple application subsystems, addition of new agents, and incorporation of existing applications. It should also be transparent; users should not need to know where their requests are being executed, nor how. Finally, in order to facilitate the user's delegating tasks to agents, the architecture will be served byamultimodal interface, including pen, voice, and direct manipulation. Design considerations taken to support this functionality will be discussed below. INTRODUCTION Agents are all the rage. #Visioneering" videos, suchas Apple Computer's Knowledge Navigator, have helped to popularize the notion that programs endowed with agency, if not intelligence, are just around the corner. Soon, users need not themselves...