AI agents can decide what to buy but mostly can't pay for it. The practical ways to give an agent payment authority, with tradeoffs and working code.
You hand your agent a task: pull the latest pricing for three competitors and summarize it. It finds the report. The report sits behind a $4 paywall. The agent stops. It can read, reason, and plan, but it has no way to complete a checkout, because nobody gave it a way to pay.
The opposite failure is worse. You paste a card number into the agent's environment so it can buy what it needs, walk away for an hour, and come back to a list of charges you never approved.
Both failures come from the same gap. The hard part of agent payments is not moving money. It is giving an agent enough authority to pay for what the task needs, and no more than that.
What does an AI agent need before it can pay?
