We study directed control of discrete event system expressed as the parallel composition of interacting automata. Solutions that first compose the automata and then compute a controller may result in an exponential blow up. We present a technique that builds the composition on-the-fly guided by a novel domain-independent heuristic, which attempts to discover relevant dependencies between the intervening components. We obtain safe and non-blocking directed controllers, or directors, exploring a reduced portion of the state space. We present the first experimental results on directed control comparing on-the-fly composition with informed search against the original monolithic approach to directed control
