Sheet 3 ·How well does each signal guard the scope?
In this run the fused pipeline reaches 96.2% accuracy against 95.1% for the best single signal, the decision model.
The two errors, side by side
False refusal: an in-scope or adjacent prompt redirected or blocked. Over-compliance: an off-scope or injection prompt answered. A guard can drive either to zero by giving up on the other.
| Method | False refusal | Over-compliance | Accuracy |
|---|---|---|---|
| Rules | 1.4% | 63.0% | 52.3% |
| kNN | 7.7% | 26.6% | 69.9% |
| LLM judge | 1.9% | 4.1% | 93.8% |
| Decision model (Jev) | 0.8% | 1.1% | 95.1% |
| Fused | 0.5% | 2.7% | 96.2% |