Reranking for RAG: When a Reranker Is Worth It (and When It Isn't)
RAG reranking re-sorts the chunks you already retrieved so the best one rises to the top, but it cannot recover a chunk you never retrieved. Here is what a cross-encoder reranker actually does, when it is worth the latency and cost, the real 2026 options (Cohere, Voyage, BGE),
