Guardrails AI
Validates model output against a schema instead of hoping — and re-asks when validation fails.
The gap this fills is specific: a model returns text that is almost valid JSON, and your parser throws. Guardrails lets you declare validators and wraps the call so failures trigger a re-ask with the error included, rather than an exception in production. Its validator hub covers the common cases — PII detection, toxic language, competitor mentions, URL reachability — and you can write your own. Treat it as defence in depth, not as a safety guarantee: validators catch classes of error, not all of them.
Best for: Structured output that must parse reliably, and PII or policy checks before content reaches a user