Augmenting a model in a model-driven application development architecture, including defining a task to be performed on at least one model item of a principal model, where the principal model is configured to facilitate the automatic generation of at least one resource for use by a computer-executable application, identifying at least one model item required for use the task that is absent from the principal model, defining the absent model item in a decoration model, mapping the decoration model to the principal model, and storing both of the models on a computer-readable medium.