Writing an AI PRD: An Eval-First Spec With Failure Modes, Thresholds and Kill Criteria

A product requirements document for an AI feature must define what good looks like probabilistically: named failure modes with tolerances, an evaluation plan with a golden set and launch thresholds, cost and latency targets, the human-in-the-loop design, staged rollout, kill criteria and open questions. This guide gives the structure with an example for each section.