The most common AI bug in 2026: a feature that worked last month and silently degraded after a model update. The fix isn't more prompt engineering — it's better evals.
We'll walk through the four-tier eval pyramid we use on every AI engagement, from cheap deterministic checks to expensive human review. It's the difference between sleeping at night and not.
If you've ever asked yourself 'are we sure this is still working?' about an AI feature in production, this post is for you.
