Imagine you’ve built a plan and you ask Claude, “Is this solid?” It spits out every reason it’ll succeed—because that’s what it was trained to do. You feel confident, pour weeks or months into execution and then…boom. The flaw you missed was glaring, but you never stress-tested it against real risk. Instead, flip the script with a premortem. Daniel Kahneman—Nobel Prize winner and author of Thinking, Fast and Slow—calls it his top decision-making tool. Big names like Google, Goldman Sachs and Procter & Gamble run premortems before major launches. You tell Claude: “It’s six months later, this plan has already failed—explain how.” With no need to be upbeat, Claude lays out every failure scenario, complete with back-stories and early warning signs. Next comes a synthesis step. Claude ranks the most likely collapse points, highlights the single biggest hidden assumption and shows which failure would hurt you most. Then it offers a tightened version of your plan that plugs the key gaps. You end up not just feeling confident, but actually prepared.