LinkedIn’s live A/B raised support-agent self-service, but what happened afterward? A separate Taobao trial offers a useful measurement countercheck: giving 5,940 human support workers optional AI diagnoses and replies improved rated chats, yet did not detectably reduce three-day same-issue returns overall. It was a January–February 2024 *human-copilot* test, not proof about LinkedIn’s 2026 autonomous agent. The two endpoints need measuring together.