The Roles of Roles in Agent Communication Languages

We consider agents having multiple communication sessions at the same time. We assume that FIPA semantics of agent communication languages can still be used when we attribute mental attitudes for each session, which we call the roles of the agents, and we assume that we have to distinguish the mental attitudes attributed to the roles from the mental attitudes of the agents. We consider several consequences of the distinction between the mental attitudes attributed to the roles and the mental attitudes attributed to the agent. First, in attributing mental attitudes to an agent or to one of its roles, we argue that only mental attributes are attributed to an agent’s role when these attributes follow directly from the agent’s communication. They are therefore public in the sense that every agent who has overheard the session, has the same beliefs about the mental attitudes of the role. Second, the moves permitted to the dialogue participants in the same dialogue game are based on the role only, such that different kind of moves can be specified in different types of dialogue games. Obligations are associated to roles related to institutions which can enforce them by means of sanctions. Third, expectations are based both on the mental attitudes ascribed to the agent and to the role. 1 Multiple sessions at the same time Consider an agent who informs another agent that his web services can be used by all other agents, informs a third agent that his services can only be used by agents with the appropriate certificates, requests from a fourth agent a document, and informs a fifth agent that he does not have a goal to obtain this document. The semantics of speech acts in mentalistic approaches like FIPA [8], specified in terms of plan operators whose preconditions refer to the beliefs, goals and intentions of agents, cannot model such an insincere agent. In this paper we therefore generalize the FIPA model for the various sessions or dialogues of such an agent