This work focuses the circumstantial knowledge management for a specific need: the achievement of Natural Interaction (NI). In first place, a cognitive approach to NI is glanced as the framework for such knowledge management. This approach reflects some certain requirements for the whole interaction system, which are met by a multi-agent system implementation. Finally, a Situation Modeling is proposed for a first approach to the interaction circumstances management.The presented work has been developed within the MAVIR project (S-505/TIC/0267) endorsed by the Regional Government of Madrid, and is being extended through the SOPAT project (CIT-410000-2007-12), supported by the Spanish Ministry of Science and Education.Publicad