The ability to act and respond to exogenous events in dynamic environments is crucial for robust autonomy. In dynamic environments, external changes may occur that prevent an agent from reaching its goal(s). I am interested in the design of reasoning and planning components operating in environments that undergo changes in real time. My goal is to develop a framework for fully integrated planning, execution and vision in dynamic environments. In the initial phase of this work, we have concentrated on the problem of enabling a planning system to deal with relevant changes in the environment during planning time. We introduce a new system for planning in a world under continuous change in an agent with visual perception. Our main contribution is to make vision sensitive to relevant changes in the environment that can affect an agent plans. We applied a rational-based monitor technique [Veloso et al., 1998] to the SHOP Hierarchical Task Network (HTN) planner [Nau et al., 1999]. We modifified SHOP to generate plan monitors to interact with a vision system and react only to those environmental changes that bear on current planning decisions. Thus when the monitors detect any relevant changes, corresponding plan transformation are executed as needed