Evaluating LLM Quality Without Vibes

The dirty secret of shipping LLM features is that most teams have no real regression suite. Model upgrades go to production based on a small handful of spot checks and a vibe. That works until it doesn't, usually noisily, in front of a customer.

Teams that have built proper eval infrastructure share a common pattern: a labeled golden set that grows with every customer-reported failure, a cheap and fast model-judged eval that runs on every change, and a slower expert review on a sampled basis. None of this is glamorous, and all of it pays for itself the first time a vendor silently changes a model.