Due to more and more mobile computers moving among smart and communicating devices in our everyday life, we observe the emergence of new constraints in software design. Indeed, device heterogeneity, dynamic software variation, and frequent mobile device apparition/disappearance make software applications compulsorily adapt to their context. In this paper, we will present an enhancement of ambient computing discovery mechanisms adding context handling capabilities to Web Services for Devices. As a matter of fact, we define contextual parameters for broadcast requests so that only devices in the "selected context" reply, which aim at reducing the overall number of exchanged messages on the network.