What problem does it solve? After optimizing a skill, there is no objective way to know whether the changes actually improved it. This Skill measures skill quality on held-out eval prompts with a strict LLM judge, so you can quantify the lift from optimization instead of guessing. ## Core Features & Use Cases - Held-out eval sets: Builds representative prompt/rubric pairs from saved bench files, mined trace spans, or synthesized prompts, sampled deterministically with fixed seeds. - Reproducible scoring: Judges each skill's SKILL.md as instructions on a 1-5 scale against rubrics, with identical scores for identical skill text and seeds. - Before/after comparison: Scores the current skill against its most recent backup to report the delta from optimization, flagging regressions and suggesting a restore. - Use Case: After running an optimization pass on your skills, ask to bench them with seed 42 and receive per-skill mean scores, per-prompt breakdowns, and an overall lift report. ## Quick Start Ask the assistant to bench your skills with max 5 samples and seed 42 to get a scored quality report.