Doubt every decision in a plan, doubt the doubts, and answer each from real evidence — codebase context for code doubts, Exa for world doubts — or flag it for the human. Iterate until the plan produces no new load-bearing doubt (convergence). 20 is a hard ceiling, never a target.

Args: prompt: the task / plan to harden. context: real evidence (paste relevant files, types, tests, notes) used to resolve code doubts without guessing. max_passes: convergence ceiling (clamped to 20).

Returns: {passes_used, converged, plan, doubt_log, needs_user, engine, open_doubts}

Exa deep search -> cited, confidence-scored facts (used inside the loop). Low confidence is reported as UNKNOWN and never asserted.

Gate a doubt() result. Proceed only if the plan converged with no open load-bearing doubt remaining; otherwise return the blocking questions.