We present a system that enables applications to discover and obtain information that describes the context of a particular entity (e.g., a user or a device). Our system revolves around the notion of a context agent, which is a service that represents an entity and provides access to context information about that entity. Context agents facilitate the enforcement of an entity?s policies regarding the release of context information (e.g., to applications or visiting users), even while these entities roam across different administrative domains. Context agents form an overlay on top of traditional local area service discovery infrastructures (e.g., based on SLP or WS-Discovery) and are enablers for more intelligent pervasive computing environments. In this extended abstract, we outline the architecture of our system based on a simple scenario.