The Agents in Grid project is devoted to the development of an agent-based intelligent high-level Grid middleware. In the proposed system, all data processing is ontology-driven, and initially was based on an in-house developed mini-ontology of the Grid. Our recent analysis has indicated that we should adapt and utilize the Grid ontology developed within the framework of the CoreGRID project. This note outlines how we have modified and extended the CoreGRID ontology to fulfill the needs of our approach.