We are building a software development environment that uses constraints to ensure the consistency of the different artifacts associated with software. This approach to software development makes the environment responsible for detecting most inconsistencies between software design, specifications, documentation, source code, and test cases. The environment provides facilities to ensure that these various dimensions remain consistent as the software is written and evolves. The environment works with the wide variety of artifacts typically associated with a large software system. It handles both the static and dynamic aspects of software. Moreover, it works incrementally so that consistency information is readily available to the developer as the system changes. The demonstration will show this environment and its capabilities.