PAI Drift Correlation Engine (Component #4)
Per PHASE1-TZ-001 Section 7 / P0-1 Section 7.4.
Cross-dimension drift correlation across 7 monitored dimensions:
| Dimension | Source | Weight |
|---|---|---|
| Identity changes | Consent / Delegation mutations | 1.0 |
| Objective adjustments | Objective Registry mutations | 1.5 |
| Personalization modifications | Identity Layer changes | 1.0 |
| Classification rule updates | Tier reassignments | 2.0 |
| Upgrade events | Governance logic changes | 2.0 |
| Upgrade frequency | Count per rolling window | 1.0 |
| Governance modifications | Enforcement scope changes | 2.5 |
Architecture
- Time-based rolling window: events older than
window_secsare expired on everyrecord()call. - Per-dimension score = sum of deltas within the window.
- Composite score =
sum(weight_i * dim_score_i). - When
composite >= threshold,record()returnstrueand [DriftReport::breached] is set — the caller MUST activate Conservative Mode. - Thresholds are immutable once the engine is constructed (absent Amendment — DFT-I5).
Invariants
- DFT-I1: Dimension scores are monotonically non-decreasing within a window until events expire.
- DFT-I2: Window eviction is time-based (old events expire).
- DFT-I3: Composite score is deterministic for the same event sequence.
- DFT-I4: Threshold breach always signals Conservative Mode.
- DFT-I5: Thresholds are immutable after construction.