Cooperative Information Systems (CIS) become relevant to integrate different kinds of systems so as to work collaboratively for a common goal. CIS are considered by nature as dynamic systems, and one of the most difficult problems is how to model and control multiple simultaneous interactions among agents in a friendly way. Consequently, expressiveness becomes a problem related to the representation so far, the similar systems cope neither with the problem of expressiveness nor with multiple interactions in a satisfactory way. It is proposed an integrated methodology based on Coloured Petri Nets (CPN) in order to model the interaction mechanism in a CIS and reduce the associated complexity in the representation of the dynamic of the system. The methodology integrates mainly: (a) the action basic loop in order to represent the system interactions and to model organization conversations, (b) the CPN in the interaction design and system simulation, (c) the communicative acts of FIPA (Foundation for Intelligent Physical Agents), included in the Agent Communication Language Specification.
