Measure task-specific metrics, because a single accuracy number hides the failures that matter for each system type. For RAG, track faithfulness and groundedness (is the answer supported by retrieved context?), context precision and recall, and answer relevance. For agents, track tool-call accuracy (right tool, right arguments), task completion, step efficiency, and budget adherence. For chatbots, track helpfulness, tone and instruction-following, refusal correctness, and safety. All three share latency, cost per request, and error rate. The point is to grade the thing that actually breaks: a RAG system that retrieves badly and a chatbot that ignores instructions fail in different ways, and one combined score would let both slip through.