# Auto-VEX Generation from Smart-Diff

## Module
Scanner

## Status
VERIFIED

## 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.
  - `src/Scanner/StellaOps.Scanner.WebService/Endpoints/SmartDiffEndpoints.cs` - API now embeds VEX candidates in SARIF responses.
- **API Endpoints**:
  - `src/Scanner/StellaOps.Scanner.WebService/Program.cs` - Registers SmartDiff endpoints and SmartDiff repositories in API DI.
  - `src/Scanner/StellaOps.Scanner.WebService/Endpoints/SmartDiffEndpoints.cs` - Exposes scan-scoped VEX candidate/review routes and candidate lookup routes.
  - `src/Scanner/StellaOps.Scanner.WebService/Services/InMemoryScanMetadataRepository.cs` - Resolves scan metadata for scan-scoped candidate APIs.
  - `src/Scanner/__Tests/StellaOps.Scanner.WebService.Tests/SmartDiffEndpointsTests.cs` - API behavioral coverage for candidates, review, and SARIF embedding.

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

## Verification
- Run ID: `run-001` (2026-02-12 UTC).
- Tier 0 source verification: `docs/qa/feature-checks/runs/scanner/auto-vex-generation-from-smart-diff/run-001/tier0-source-check.json`.
- Tier 1 build/test evidence: `docs/qa/feature-checks/runs/scanner/auto-vex-generation-from-smart-diff/run-001/tier1-build-check.json`.
- Tier 2 API verification: `docs/qa/feature-checks/runs/scanner/auto-vex-generation-from-smart-diff/run-001/tier2-e2e-check.json`.