Approval Mode prepares personalized messages but leaves each one in the review queue until a team member approves it.
Autonomous Mode can send eligible messages without per-message approval after an administrator explicitly enables the agent.
Autonomous Mode still enforces consent/suppression checks, address verification policy, send windows, daily limits, mailbox limits and stop-on-reply behaviour.
Recommended rollout: begin in Approval Mode, review real outputs and conversion quality, then enable Autonomous Mode only for a narrow ICP and controlled daily volume.