Transfer capability, not documents
A handoff is complete when the accountable operating team can exercise the service's critical capabilities without hidden delivery-team dependence. Name the service owner, support roles, escalation authority, change approvers, evaluation owner, incident commander, and retirement authority. Documentation supports those roles; it does not prove them.
Run exercises for normal support, evaluation regression, configuration or model change, incident containment, rollback, restore, access revocation, cost breach, and retirement. Capture who acted, what evidence they used, where they hesitated, and which gaps remain.