We are evaluating a controlled Preview-deployment workflow and need to understand which guarantees Vercel supports. During a bounded interval, we want to preserve an existing deployment inventory while allowing one designated Deploy Hook creation and its expected branch-alias update. Is there a documented combination of controls that covers competing administrative/API/hook operations, previously accepted or queued work, exact-deployment retention, and evidence of uninterrupted control after a client restart? We understand that restricting deployment sources, observing settings, and examining audit logs are different from preventing every competing change. We are not assuming a single platform lock exists. Please point us to authoritative documentation or identify which guarantees are not supported. We are deciding whether this workflow needs a different design—not requesting changes to an account or asking for custom-code debugging.