The intelligent use of tools is a general and important human competence that AI research has not yet examined in depth. Other fields have studied the topic, however, with results we can compile into a broad characterization of habile (tool-using) agents. In this paper we give an overview of research on the use of physical tools, using this information to motivate a set of requirements for building artificial habile agents. We describe the design of a habile robot, based on the Aibo platform, that can pick up a stick and use it as a tool to reach objects otherwise out of its range. We argue that analysis of activities of such tool-using agents offers an informative way to evaluate intelligence.