A mistake can reveal a missing instruction that confidence had allowed everyone to overlook.

Where everyone involved is competent, a mistake is rarely about carelessness. It usually marks the spot where an instruction was never actually given, and confidence hid the gap because experienced people fill it automatically without noticing they are filling anything. The hole only becomes visible when somebody new walks straight into it. The error is a discovery more than a fault.

After something goes wrong, ask what a person would have needed to know in order to get it right. Write that down where the work happens rather than in a message that scrolls away.