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...

... for human-computer dialogue. One of the major features of face-to-face communication is its multi- plicity of communication channels that act on multiple modalities. To realize a natural multimodal dialogue, it is necessary to study how humans per- ceive information and determine the information to which humans are sensitive. A face is an independent communication channel that conveys emotional and conversational signals, encoded as facial expressions. We have developed an experimental system that integrates speech dialogue and facial animation, to investigate the effect of introducing communicative facial expressions as a new modality in human-computer conversation. Our experiments have showen that facial expressions are helpful, especially upon first contact with the system. We have also discovered that featuring facial expressions at an early stage improves subsequent interaction.