For agents to act in collaboration, they often require an agreement that describes how they are to act, to which they are committed. Typically, agreements are characterised as an explicit course of action or a goal to be achieved. In this paper, it is argued such agreements may over specify the interaction required. To overcome this problem, a novel formalisation of agreements between agents is presented that is based on rights as well as actions to be performed. Each agent that is involved in an agreement is bound to uphold the rights of others, and the implications of exercising rights and acting for others. It is argued that this approach provides agents with greater flexibility in the agreements they may reach, while retaining the necessary group commitment.