Reference · Cheatsheet

Re-rank patterns

Retrieve wide, re-rank narrow.

Retrieve wide, re-rank narrow.

Pipeline

1. **Keyword** BM25 top-20 (SKUs, codes, exact phrases)

2. **Vector** top-20 (paraphrases, concepts)

3. **Merge** dedupe by chunk ID

4. **Cross-encoder** score pairs → top-5

5. **LLM** generate with citations

When to skip re-rank

  • Tiny corpus (<200 chunks) — vector-only may suffice
  • Strict latency budget <200ms total

Tuning

  • Raise retrieve k before lowering re-rank k
  • Log MRR or human thumbs on golden queries
  • **Related:** glossary `cross-encoder`, `re-ranking`, `hybrid-search`