CASA is designed as a modular, plug-and-play autonomy framework built on the Robot Operating System (ROS) ecosystem. It features a decentralized architecture where each robot runs local planners and behavior tree nodes, publishing to a shared blackboard for world-state updates. Task allocation is handled via auction-based algorithms that assign missions based on robot capabilities and availability. The communication layer uses standard ROS messages over multirobot networks to synchronize agents. Developers can customize mission parameters, integrate sensor drivers, and extend behavior libraries. CASA supports scenario simulation, real-time monitoring, and logging tools. Its extensible design allows research teams to experiment with novel coordination algorithms and deploy seamlessly on diverse robotic platforms, from unmanned ground vehicles to aerial drones.