Abstract. The development of intelligent agents is a key part of the Semantic Web vision, but how does an ordinary person tell an agent what to do? One approach to this problem is to use RDF templates that are authored once but then instantiated many times by ordinary users. This approach, however, raises a number of challenges. For instance, how can templates concisely represent a broad range of potential uses, yet ensure that each possible instantiation will function properly? And how does the agent explain its actions to the humans involved? This paper addresses these challenges in the context of a case study carried out on our fully-deployed system 1 for semantic email agents. We describe how highlevel features of our template language enable the concise specification of flexible goals. In response to the first question, we show that it is possible to verify, in polynomial time, that a given template will always produce a valid instantiation. Second, we show how to automatically generate explanations for the agent's actions, and identify cases where explanations can be computed in polynomial time. These results both improve the usefulness of semantic email and suggest general issues and techniques that may be applicable in other Semantic Web systems.