core practice · system design prompt
STAR: tough decision
Write a STAR about a hard call you made with incomplete information. Show your reasoning and what you tracked to know if you were wrong.
The mechanism
Decisions are bets you make with incomplete information. Judge them by the reasoning at the time, not the outcome. Good decisions name in advance what evidence would tell you you are wrong.
Expected evidence
starStory() returns { situation, task, action, result, metric: { name, unit, before, after }, earlyWarningSignal (how you would have known sooner) }. The checker enforces structure only: four distinct sections of 20+ words, action the longest, 150+ words total, before ≠ after, and the result section must name the metric and state its after value. Aim for 250-350 words — that is the interview bar, not the checker’s.Try this drill in the practice workspace →
Hints when you need them
- Frame it as a bet, not a certainty.
- Reversibility matters — was this a one-way door?