What problem does it solve? Prompt tweaks and model swaps silently change LLM feature behavior, and manual spot-checks on one or two inputs fail to catch regressions before they reach production. ## Core Features & Use Cases - Golden Set Creation: Curate 10-30 representative cases covering common inputs, edge cases, and past failures, stored as versioned JSON data. - Repeatable Eval Runner: Build a script that runs each case against the feature and scores output against explicit expectations, using string checks for objective criteria or LLM-as-judge for subjective ones. - Baseline Tracking: Record a baseline score and re-run evals on every prompt or model change to catch quality drops before release. - Use Case: After changing a summarization prompt, re-run the eval suite and see the score drop from 19/20 to 14/20, revealing a regression before it ships. ## Quick Start Create a golden set and eval runner for my LLM summarization feature so I can catch regressions when I change prompts or models.