[PheonixPharts]

RAG in this case is essentially the same as a recommender system so you can approach it with the same metrics you would there.

You'll need to build a data set with known correct answers but then it's basically, NDCG (Normalized Discounted Cumulative Gain) is a good place to start, MRR (Mean Reciprocal Rank) and MAP (Mean Absolute Precision) are other options. You could also just look at the accuracy of getting your result in the top K results for various thresholds for k (which can be interpreted as the "probability of getting your result in 'k' results).