CRIKEY is a planner that separates out the scheduling from the classical parts of temporal planning. This can be seen as a relaxation of the temporal information during the classical planning phase. Relaxations in planning are used to guide the search. However, the quality of the relaxation greatly affects the performance of the planner, and in some cases can lead the search into a dead end. This can happen whilst separating out the planning and scheduling problems, leading to the production of an unschedulable plan. CRIKEY can detect these cases and change the relaxation accordingly. 1 CRIKEY CRIKEY is a planner that uses relaxations to solve temporal planning problems. By successively reducing the complexity of the problem, the solutions to these relaxed problems are used to either guide the search for the unrelaxed version, or as a skeleton solution, round which a full solution can be built. CRIKEY performs forward heuristic search and can cope with metric and temporal domains and i...