An adaptation contract describes composition constraints and adaptation requirements among several services which were not initially built to interoperate with each other. The manual writing of this specification by a designer is a difficult and error-prone task, especially when services are reused taking their behavioural descriptions into account. In this paper, we present a semi-automatic approach to build adaptation contracts. To this purpose, we propose an adaptation contract design process supported by an interactive environment based on a graphical notation, and an engine capable of automatically generating contracts without any human intervention. We also present an experimental study that we carried out using the tool support that we implemented in order to evaluate our approach.