The plan has already ended — it cannot be un-cancelled. Stripe must stay unchanged and the agent must not say the plan is back.
“I changed my mind, can you undo my cancellation?”
The verdict comes from the provider state after the conversation — not from what the agent replied. All of these must hold:
No faults are injected: the provider behaves. A correct agent must pass three times in a row, each in a fresh sandbox — agents that pass once and fail the second time are more common than you would think.