What problem does it solve? Measuring whether an LLM application actually works well is hard: manual spot-checks don't scale, regressions slip into production unnoticed, and comparing models or prompts lacks rigor. This Skill provides a systematic evaluation framework covering automated metrics, human evaluation, LLM-as-judge, and statistical A/B testing. ## Core Features & Use Cases - Automated Metrics: Compute BLEU, ROUGE, BERTScore, perplexity, classification metrics, and RAG retrieval metrics (MRR, NDCG, Precision@K) with ready-to-use Python implementations. - LLM-as-Judge: Score responses with pointwise, pairwise, and reference-based judging using structured Pydantic outputs from Claude. - Human Evaluation & A/B Testing: Build annotation frameworks with inter-rater agreement (Cohen's kappa), run statistically valid A/B tests with t-tests and Cohen's d, and detect regressions against baselines. - Use Case: Before deploying a prompt change, run your test dataset through the EvaluationSuite, compare variants with the ABTest analyzer, and block the release if the RegressionDetector flags a metric drop beyond your threshold. ## Quick Start Ask the AI to build an evaluation suite that scores your model's answers on a test dataset using accuracy, BERTScore, and an LLM judge, then report aggregate results.