Thus. reactive agents can not plan ahead what they will do. But, what can be considered as a weakness is one of their strenghs because they do not have to revise their world model when perturbations change the world in an unexpected way. Robustness and fault tolerance are two of the main properties of reactive agent systems. A group of reactive agents can complete tasks even when one of them breaks down. The loss of one agent does not prohibit the completion of the whole
task, because allocation of roles is achieved locally by perception of the environmental needs. Thus, reactive agent systems are considered as very flexible and adaptive because