Autonomous agents decide for themselves, on the basis of their beliefs, goals, etc., how to act in an environment. However, it is often the case that an agent is motivated to achieve some goal, where its achievement is only possible, made easier, or satisfied more completely, by gaining the collaboration of others. This collaboration requires the agents to communicate with one another in negotiation and in the coordination of their action. In this paper, it is assumed that such collaboration requires the agents involved to have some prior agreement on the actions that each can call on the others to do; their respective rights. A novel framework is introduced for describing agreements between agents based on rights, and it is indicated how agents may generate such agreements through negotiation. In particular, we focus on a discussion of the structure of an agreement, what it means for an agent to be committed to an agreement, and the communicative actions that agents use in the generation of agreements.