Evidential Entitlement in RAG: Beyond Correctness and Citation

Retrieval-augmented generation is meant to make answers more trustworthy by grounding them in external evidence. Yet a correct answer, even with a plausible citation, does not show that the cited evidence actually backed that answer when it was generated. The same answer can follow from valid retrieval, stale evidence, an incomplete search, or retrieval failure. We call this missing property *evidential entitlement*. Entitlement depends on the relation between the current request, the evidence actually delivered, and the resulting claim. This creates a basic asymmetry: one matching source can support a positive claim, but a no-match claim also requires evidence that the relevant search was complete. We show that if these distinctions are absent from the visible output, no later evaluator can recover them, and we characterize the minimum additional information needed to preserve them. We test these predictions on official Python, Kubernetes, and Federal Register corpora across four model families. Among 11,520 pairs with different entitlement, 42.26% still produce the same correct answer. Source identity and version remove many ambiguities, but the remaining failures come from exactly the missing relations predicted by the theory: query binding and search completion. A held-out three-field interface preserves these distinctions without exposing the full execution trace.