Structured output

Schema-constrained generation removes an entire class of parsing failure. Validate anyway, a structurally valid response can still be semantically wrong.

It pairs naturally with validation. Constrain generation to the schema, then validate the values against your business rules, a well-formed date that falls outside the policy period is structurally valid and semantically wrong, and only the second check catches it.

It also changes error handling for the better. A model that must return a schema can be given an explicit field for uncertainty or refusal, so 'I could not determine this' becomes a value your code can branch on rather than a sentence someone has to parse out of prose.

Give the schema a field for uncertainty. A model forced to pick a value will pick one even when the input does not support it, whereas an explicit low-confidence option lets your code route that case to a human instead of acting on a guess.