The policy.
The thread Likelihood's Platt calibration for the model that answered, or null when that exact model has none, and routing keeps continuity.
DECISION_ROUTING_MIN_CONFIDENCE.
DECISION_ROUTING_TIMEOUT_MS: past it, production keeps continuity.
A routing policy in words:
confidence ≥ 0.7, timeout 350 ms, Likelihood calibrated (A 1.7757, B -3.3506), or…, no calibration for the answering model (keeps continuity).