Evaluating and ensuring the consistency between user requirements and modeling artifacts is a long-time issue for model-based software design. Conflicts in requirements specifications can lead to many design errors and have a decisive impact on the quality of systems under development. This article presents an approach based on Behavior-Driven Development (BDD) to provide automated assessment for task models, which are intended to model the flow of user and system tasks in an interactive system. The approach has been evaluated by exploiting user requirements described by a group of experts in the domain of business trips. Such requirements gave rise to a set of BDD stories that have been used to automatically assess scenarios extracted from task models that were reengineered from an existing web system for booking business trips. The results have shown our approach, by performing a static analysis of the source files, was able to identify different types of inconsistencies between the user requirements and the set of task models analyzed.