Errors

Use this skill whenever a design must accommodate the inevitability of human error — typos, wrong-button presses, misread instructions, mistimed actions, misunderstandings of system state. Trigger when designing form validation, input handling, destructive flows, complex multi-step procedures, alert systems, or any UI where users can do the wrong thing. Trigger when post-incident analyses reveal patterns of "human error" — most are design errors in disguise. Errors is one of the foundational principles in 'Universal Principles of Design' (Lidwell, Holden, Butler 2003), grounded in Norman's and Reason's foundational human-error research.