In this thesis we present preliminary results in the development of LIBRA (LInköping Behavior Representation for Agents). LIBRA is a rule-based system for specifying the behavior of automated agents that combine reactivity to an uncertain and rapidly changing envi-ronment and coordination. A central requirement is that the behavior specification should be made by users who are not computer and AI specialists. Two application domains are considered: air-combat simulation and a simulated soccer domain from the perspective of the RoboCup competition. The behavior of an agent is specified in terms of prioritized production rules organized in a decision tree. Coordinated behaviors are encoded in the decision trees of the individual agents. The agents initiate tactics depending on the situation and recognize the tactics that the other team members have initiated in order to take their part in it.What links individual behavior descriptions together are explicit communication and common means to describe the situation the agents find themselves in.