The GOODLY language can be used to specify the design of systems built according to the Object Oriented paradigm. It was conceived with the main purpose of facilitating the extraction of MOOD2 design metrics, an extension of the original MOOD set [Abreu94]. It allows expressing the most relevant design information for that purpose, such as the class structure with corresponding inheritance relations, uses relationships, message exchanges and information hiding. This language, whose syntax and semantics are fully described, is being used in the production of a new generation of the MOODKIT tools that allow the MOOD2 metrics extraction.