# rag-knowledge-retrieval Delta

## MODIFIED Requirements

### Requirement: Knowledge retrieval SHALL deduplicate evidence blocks

The retrieval flow SHALL remove duplicate evidence blocks before returning them to the Agent. Duplicates are defined by chunk-level `evidenceKey` identity, not by document source alone.

#### Scenario: Chunk-level deduplication keeps distinct chunks

- **WHEN** L1 produces multiple candidates with the same source but different chunk identities
- **THEN** the retrieval flow SHALL keep separate evidence blocks for those chunk identities subject to per-document caps
- **AND** SHALL NOT collapse them solely because source is equal

#### Scenario: Same evidenceKey collapses

- **WHEN** two candidates share the same evidenceKey
- **THEN** the retrieval flow SHALL keep a single evidence block for that identity
- **AND** the evidence block SHALL preserve hit reasons from both paths when available

#### Scenario: Postprocess count tracking

- **WHEN** evidence post-processing completes
- **THEN** the tool invocation details SHALL record candidate count and final evidence block count