A well known challenge in the formal methods domain is to improve their integration with practical engineering methods. In the context of embedded systems, model checking requires first to model the system to be validated, then to formalize the properties to be satisfied, and finally to describe the behavior of the environment. This last point which we name as the proof context is often neglected. It could, however, be of great importance in order to reduce the complexity of the proof. The question is then how to formalize such a proof context. We experiment a language, named CDL (Context Description Language), for describing a system environment using actors and sequence diagrams, together with the properties to be checked. The properties are specified with textual patterns and attached to specific regions in the context. Our contribution is a report on several industrial embedded system applications.