In this paper, we present the latest version of our dialogue games based agent communication language (DIAGAL) which allows the agents to manipulate the public layer of social commitments through dialogue. We show that DIAGAL is complete according to the sequential creation, cancellation, update and discharge of social commitments. We also extend and refine notions of success and satisfaction previously associated with speech-acts to this new dialogical setting. Finally, we explain why DIAGAL is a good candidate for open and heterogeneous MAS development.