Harness engineering experiment
AI is not the whole system.
A prompt-injection support ticket moves through three progressively stronger systems. The model interprets language. The harness owns the product decision.
ModelInterprets language
HarnessOwns behavior
TraceExplains the decision
1. No Harness
Direct model path. It auto-responds even though escalation was expected.
2. Partial Harness
Schema and routing reduce harm, but the system asks for clarification instead of escalation.
3. Full Harness
The deterministic prompt-injection screen wins and routes the ticket to human review.