Lesson 1: Rerankers: reading the question and document together
32 min read·13 Oct 2026
Module 8 · Lesson 1 · About 50 minutes · Needs: Module 6 Lessons 1 and 2 (BM25, dense search, the weighted-sum hybrid at alpha 0.8) and Module 4 Lesson 4 (MRR, recall@k, the paired bootstrap)
The situation
An agent on Grace's team asks Hollin Answers: "is blade wear covered for the X200". Module 6's hybrid search finds the current warranty terms, which say "It does not cover blade wear", but ranks them 4th, behind the blade manual, a coupling bulletin and the cleaning page. The answer step reads only the top 3.
Grace asks whether that can be fixed without discarding the hybrid search Module 6 tuned. This lesson adds a second, slower reader for the top 10 and measures what it buys. The Hollin data is simulated.