Use of knowledge-based decision aids can help alleviate the challenges of planning complex military operations. We describe the CADET system, a knowledge-based tool capable of producing automatically (or with human guidance) Army battle plans with realistic degree of detail and complexity. In ongoing experiments, it compared favorably with human planners. Tight interleaving of planning, adversary estimates, scheduling, routing, attrition and consumption processes comprise the computational approach of this tool. Although originally developed for Army large-unit operations, the technology is generic. In this paper, we focus particularly on the engineering tradeoffs in the design of the tool, and on the experimental comparative evaluation of the tool’s performance.