In the context of the ESPRIT project DAIDA, we have developed an experimental environment intended to achieve consistency-in-the-large in a multi-person setting. Our conceptual model of configuration processes, the CAD$,^∘$ model, centres around decisions that work on configured objects and are subject to structured conversations. The environment, extending the knowledge-based software information system ConceptBase, supports co-operation within development teams by integrating models and tools for argumentation and co-ordination with those for versioning and configuration. Versioning decisions are discussed and decided on within an argument editor, and executed by specialised tools for programming-in-the-small. Tasks are assigned and monitored through a contract tool, and carried out within co-ordinated workspaces under a conflict-tolerant transaction protocol. Consistent configuration and reconfiguration of local results is supported by a logic-based configuration assistant.