git.stella-ops.org/docs/features/checked/scanner/false-negative-drift-tracking-and-metrics.md

False-negative drift (FN-Drift) tracking and metrics

Module

Scanner

Status

VERIFIED

Description

FN-Drift calculation, metrics export, and classification change history tracking with dedicated Postgres migration.

Implementation Details

• FN-Drift Calculation:
  • src/Scanner/__Libraries/StellaOps.Scanner.Storage/Services/FnDriftCalculator.cs - Calculates false-negative drift metrics
  • src/Scanner/__Libraries/StellaOps.Scanner.Storage/Services/FnDriftMetricsExporter.cs - Exports FN-Drift metrics for telemetry
• Classification Change Tracking:
  • src/Scanner/__Libraries/StellaOps.Scanner.Storage/Services/ClassificationChangeTracker.cs - Tracks classification changes over time
  • src/Scanner/__Libraries/StellaOps.Scanner.Storage/Models/ClassificationChangeModels.cs - Change models
  • src/Scanner/__Libraries/StellaOps.Scanner.Storage/Repositories/IClassificationHistoryRepository.cs - Repository interface
  • src/Scanner/__Libraries/StellaOps.Scanner.Storage/Repositories/ClassificationHistoryRepository.cs - PostgreSQL repository

E2E Test Plan

• Run multiple scans over time and verify FnDriftCalculator computes drift metrics based on classification changes
• Verify classification change history is persisted and queryable
• Verify FN-Drift metrics are exported to the telemetry system
• Verify classification changes (e.g., vulnerable -> not_affected -> vulnerable) are tracked with timestamps
• Verify drift metrics accurately reflect the rate of false-negative changes over time

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Verification

Check	Result
Tier 0 - Source files exist	PASS
Tier 1 - Build + code review	PASS
Tier 2 - Integration tests	PASS
Verified	2026-02-13T18:10:00Z