untangle

Use when a problem resists a plan and starting work would be guessing. Triggers on: 'I have no idea why', 'this makes no sense', 'we tried everything', 'it works locally but not in prod', 'intermittent', 'flaky', 'which approach should we take', 'weigh the options', 'trade-offs', 'I keep going in circles', 'this is a hard one'. Fits an unclear cause, contradictory evidence, several theories that all fit, a fix that keeps not working, or a design with three defensible answers where choosing wrong is expensive. Classifies the difficulty first (unknown cause / undecided design / too large to hold), then runs the branch for it: competing hypotheses each carrying the observation that would kill it, options scored against criteria written before the options, or a coverage map before any edit. Not for work whose shape is already known (use task) and not for reviewing finished code.