Ragas provides the measurement layer for RAG quality — define a test dataset (question, ground truth, context, answer), run the evaluation suite, and get quantitative scores for faithfulness (does the answer use only retrieved context?), answer relevancy (does the answer address the question?), context precision (is retrieved context actually relevant?), and context recall (does retrieved context cover the answer?). For agents: evaluate RAG pipeline quality programmatically, generate synthetic test sets from your corpus, track metric changes across pipeline versions. Works with any LLM (via LangChain or direct OpenAI API) for the judge model. Confidence is docs-derived.: Comprehensive Agent-Usability Assessment
Docs-backedPython SDK: pip install ragas. Evaluate: from ragas import evaluate; from ragas.metrics import faithfulness, answer_relevancy, context_precision, context_recall; from datasets import Dataset. dataset = Dataset.from_dict({"question": ["..."], "answer": ["..."], "contexts": [["ctx1", "ctx2"]], "ground_truth": ["..."]}). result = evaluate(dataset, metrics=[faithfulness, answer_relevancy, context_precision, context_recall]). result.to_pandas() → DataFrame with per-question scores. Synthetic test set: from ragas.testset import TestsetGenerator; gen = TestsetGenerator.with_openai(); testset = gen.generate_with_llamaindex_docs(documents, test_size=100). LangChain integration: RagasEvaluatorChain wraps evaluation chain. Custom LLM judge: metrics accept llm parameter for any LangChain-compatible LLM.