Faithfulness: does the generated answer contain only information supported by the retrieved context?

Faithfulness: does the generated answer contain only information supported by the retrieved context? Measures hallucination. Relevance: is the answer responsive to the user's question? A response can be faithful (all claims grounded) but irrelevant (answers a different question). Measure faithfulness with NLI or LLM-judge checking claim-by-claim. Measure relevance with semantic similarity between query and answer.