The key to simplifying development and execution of large and complex distributed systems is providing adequate development environment and runtime facilities for supporting cooperation, reliability and dynamic adaptation. This paper focuses on analytical tools that assist in development of complex systems. The environment allows scalable specification of complex application behavior using mechanisms for abstracting group behavior and hierarchical composition of components. Behavior specification of applications can be analyzed automatically for two classes of problems: (1) reachability and liveness, and (2) consistency during failure recovery and dynamic adaptation. Consistency is preserved by automatically analyzing dependencies from behavior specification. This approach permits components of a complex system to cooperate in complex ways, and execute continuously for a long time with minimal disruption, despite failure or adaptation of some components.