In tangible irreversible human-machine interactions (HMIs), erroneous inputs resulting from users’ unfamiliarity, inattention, or ingrained habits can lead to unintended consequences. Although some design measures like buttons with protective shells or safety switches before critical actions have been implemented to minimize human errors in both everyday products and industrial interfaces, a cohesive guiding strategy on when, where, and how to prevent unintended consequences is lacking. Inspired by the confirmation dialog boxes commonly utilized in graphical user interfaces, this study proposes design strategies for effective tangible confirmation behaviors in HMIs. Initially, a workshop was conducted to gather design cases and explore potential design opportunities in future scenarios. By analysing the outcomes, we propose an evaluation method for assessing the necessity and complexity requirements of confirmation design and introduce a design library considering complexity levels graded by users’ time, effort, and cognitive load expenditure. Subsequently, a user behavior experiment was conducted to validate the feasibility and efficacy of the proposed strategies. Our strategies offer valuable references for designers, highlighting the significance of confirmation design in preventing human errors. Following these strategies, designers and engineers can integrate more Kansai engineering principles into HMIs to ensure user safety, protect property, and enhance interaction efficiency.