In this paper we present a method and the related tool for analysing Web site code in order to automatically reconstruct the underlying logical interaction design. Such design is represented through task models that describe how activities should be performed to reach users' goals. The models also include a specification of the objects that should be manipulated to accomplish such tasks. We also discuss how the result of this reverse engineering process can be provided as input to a number of tools for various purposes (model analysis, usability evaluation, user interface redesign for different interactive platforms).