# Auto-VEX Generation from Smart-Diff

## Module
Scanner

## Status
IMPLEMENTED

## Description
VEX candidate emission from SmartDiff detection results, generating VEX statements backed by delta evidence.

## Implementation Details
- **VEX Candidate Emission**:
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/Detection/VexCandidateEmitter.cs` - Emits VEX candidates from SmartDiff detection results
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/Detection/VexCandidateModels.cs` - VEX candidate data models
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/Detection/VexEvidence.cs` - Delta evidence backing VEX statements
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/Detection/Repositories.cs` - Repository interfaces for VEX candidate persistence
- **SmartDiff Predicate**:
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/SmartDiffPredicate.cs` - SmartDiff predicate model including VEX data
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/Detection/ReachabilityGateBridge.cs` - Bridges reachability gate data into SmartDiff VEX candidates
- **SARIF Output**:
  - `src/Scanner/__Libraries/StellaOps.Scanner.SmartDiff/Output/SarifOutputGenerator.cs` - SARIF export including VEX candidate data
- **API Endpoint**:
  - `src/Scanner/StellaOps.Scanner.WebService/Endpoints/SmartDiffEndpoints.cs` - `SmartDiffEndpoints` exposes VEX candidates via REST (`VexCandidatesResponse`, `VexCandidateDto`, `ReviewRequest`)

## E2E Test Plan
- [ ] Scan two versions of the same image to produce a smart-diff delta
- [ ] Call `GET /api/v1/smart-diff/{scanId}/vex-candidates` and verify VEX candidates are returned
- [ ] Verify each VEX candidate includes evidence links referencing the specific delta changes
- [ ] Submit a review decision via `POST /api/v1/smart-diff/{scanId}/vex-candidates/review` and verify the candidate status updates
- [ ] Export the SARIF output and verify VEX candidate data is embedded in the SARIF report
- [ ] Verify VEX candidates include reachability gate context when gates are detected