A city MLOps policy covers progressive rollout of resident-facing scores. What operational readiness item is required before traffic shifts?

Documented rollback owners assigned before progressive rollout begins is correct because city MLOps policy for resident-facing scores must include operational readiness, not only traffic-splitting mechanics. Naming who can and will execute rollback—and documenting that ownership before any progressive shift—ensures rapid reversion when scores misbehave, dashboards light up, or SLOs breach. Without assigned owners, progressive rollout becomes a shared assumption that nobody is accountable to reverse under pressure.

Documented legacy endpoint retired before progressive rollout begins fails because retiring the fallback before any shift removes the safe reversion target rather than establishing readiness to roll back.

Documented prior model artifacts archived before progressive rollout begins fails because archiving takes the fallback out of ready use rather than keeping the prior version available and deployable for rapid reversion.

Documented rollback observers assigned before progressive rollout begins fails because observers can only watch rather than execute reversion, lacking the accountable authority and access that named owners must have before the shift.

Exam caveat: when stems ask what is required before traffic shifts under progressive rollout policy, look for pre-assigned rollback ownership and related readiness artifacts—not rollback observers assigned for watching or prior model artifacts archived out of ready use.

Operational check: before shifting resident-facing traffic, record named rollback owners (primary/backup), confirm they have rights to revert the endpoint or deployment, verify the prior model version remains available, and rehearse the rollback communication path in the municipal runbook.