Microsoft Spec Explorer is a tool for Model-Based Testing that runs as an add-in to Visual Studio Ultimate/Team Suite editions. Spec Explorer is a visual tool for modeling software behavior and generating test suites from those models. Spec Explorer's approach to model-based testing has been shown to greatly enhance productivity of test case creation, to ensure predictability of requirement coverage, and to support lifecycle management and software updates. Models are typically written in C# and controlled by a configuration language which allows to express scenarios and test purposes.