LLM Model Regression Testing: Catch Quality Drops Before Users Do
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LLM Regression TestingAI EvaluationModel QualityLLM Ops
LLM behavior can change when prompts, providers, models, retrieval settings, or tool definitions change. Regression testing helps catch quality drops early.
Test set design
Include common cases, edge cases, previous failures, structured output tasks, and high-value customer workflows.
When to run tests
Run regression tests before:
- prompt changes
- model upgrades
- provider migration
- routing changes
- retrieval changes
What to measure
Track correctness, format compliance, latency, cost, refusal behavior, and user-facing quality.
Final thoughts
LLM regression tests make AI changes safer. Treat prompts and models like production dependencies that need testing.