Abstract: Autonomous agents are believed to have control over their internal state and over their behaviour. For that reason, an agent should control how and by whom it is being influenced. We introduce a reasoning component for BDI-agents that deals with the control over externalinfluences, and we propose heuristics using local knowledge to process incoming stimuli. One of those heuristics is based on information relevance with respect to the agent's current plans and goals. We have developed a way to determine the relevance of information in BDI-agents using magic sets from database research as basis. The method presented shows a new application of magic sets by applying the theory in agent systems.