There is no way you can measure your AI drift. variA/Bly helps you evaluate and A/B/n test prompts scientifically, so you catch issues before users complain. Differentiator: → 41-dimensional evaluation -quality scored across multiple dimensions → Statistical A/B testing - confidence intervals, not gut feeling → AI-powered optimization - generates better prompts from data → Prompt Registry - version control and deployment Other tools wait for user complaints. variA/Bly measures continuously.