The paper describes and discusses a prototype tool (TUNE) for computer-supported evaluation of guideline and style guide compliance in user interfaces. The aim of the tool is to facilitate the use of human factors knowledge, in the form of guidelines and style guides, GLSG, when developing user interfaces. After discussing the increased interest in GLSG compliance and reasons for computer-support in this area, TUNE is presented, together with experiences from practical use. With these experiences as a basis the possible benefits in using the tool to evaluate GLSG compliance is discussed. The paper finally presents the future development of TUNE, for example implementing more GLSG