This paper introduces teams of personal agents that support users individually in electronic negotiations. These agents listen to the running negotiation and to each other to point out relevant information and compile advice for the user. In this frame, we first describe the architecture of this system and propose assistance interaction protocols to specify agent external behaviours in performing their tasks. Then, we discuss the semantic representation of agent communication and describe an abstraction layer to let agents understand user message issues. Our future work aims at improving these mechanisms and enriching them toward a full-fledged implementation.