Over the last two years we have been designing and implementing an architecture for environments along with an instantiation of that architecture as a C++ programming environment. To do this we have examined the most effective environments—programming or otherwise—and gathered features we would like to see in next-generation environments, and from this we have designed a minimal set of constructs. Among the most difficult to achieve is tight integration without implementing all tools as a monolith. The result is a prototype of a very tightly integrated C++ environment to which it is easy to connect additional C++ programming tools, CASE tools, configuration management tools, and documentation support tools. The environment can be easily extended for multi-programmer groups. Written entirely in C++, this environment uses advanced object-oriented programming techniques and provides persistent C++ instances. A new paradigm for integration— annotations—has been developed which unifies control integration, data integration, and user interfaces.