# Brief: rag-quality-score-unify

## Background

True BM25 hybrid retrieval is live, but post-processing still normalizes as if every score were dense L2 and re-ranks with L0 keyword contains boosts. That splits ranking authority from quality gates and double-counts lexical signal.

## Goals

- Unify score labels to `dense` | `hybrid`.
- Single `toQualityScore`; label-agnostic post-process.
- Preserve retrieval rank; remove boost re-rank.
- Hybrid quality = pure rank mapping (slice 1).

## Scope

Internal RAG pipeline: store emission, normalizer, evidence post-process, tests, architecture docs.

## Non-goals

Fine re-rankers, query rewrite, neighbor chunks, schema rebuild, ACI field renames, removing dense comparison mode.