Place review gates in a payments flow migration

Your Java payments service charges cards synchronously: the checkout request waits while the service calls the payment provider. You are moving to a queue-based flow. Checkout will record a charge request, and a worker will call the provider and record the result. An AI agent will write most of the migration, and it produces a lot of correct-looking code fast.

Where must a person review before the agent moves on, and where can it run on its own? Justify each gate by what is at stake if the agent is wrong there.