First-pass retrieval (vector or hybrid) is fast but coarse. A re-ranker is a more expensive model that re-scores the top N candidates against the query, producing a better-ordered list. Cohere Rerank, Jina Reranker, and bge-reranker are the popular options. Worth the latency for production support bots, overkill for fast triage.
Engineering notes from the Digitorn team. No marketing, no launch announcements, no "10 prompts that will change your life". Just the things we write that we'd want to read.