Explain the RAGAS evaluation dimensions, faithfulness, answer relevance, context precision, context recall, and when to trust them

Reciting the four definitions is table stakes; the differentiator is knowing which two need ground truth, what each dimension tells you to fix, and where the judge-model scores quietly lie. The 2x2 that turns RAGAS into a debugging tool.

Updated Aug 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.