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How to Let an AI Agent Shop and Check Out for You

Most "AI shopping" still stops at the cart. The agent finds the product, then hands you a link and asks you to finish the purchase yourself. Agentcard's buy tool removes that last step: you describe what you want in plain English and the agent does the whole thing — search, cart, delivery details, and checkout — paying from a virtual card after you confirm.

This is one tool, not a toolbox. There is no separate search, add-to-cart, or pay function for the agent to orchestrate. It just calls buy and has a conversation.

How the buy tool works

The whole shopping experience — searching a merchant, building a cart, collecting a delivery address, checking a budget, and checking out — runs in a server-side agent loop at Agentcard. Your agent passes your request to the buy tool and relays the assistant's reply back to you. Because the flow is conversational, the tool returns a conversation id, and each follow-up ("add a Coke," "yes, place it") continues the same order rather than starting over.

One rule the agent follows: it calls get_instructions first, which fetches the current usage guide so its behavior stays in sync with the live shopping flow instead of relying on stale, hardcoded steps.

Prerequisites

  • An Agentcard account funded with a payment method, and the CLI installed (see How to Give an AI Agent a Credit Card).
  • The Agentcard MCP server connected to your agent.
  • A merchant linked to your account (the tool lists the merchants you have connected; today that includes DoorDash and Good Eggs, with more on the way).

Step 1: Describe the purchase

Tell the agent what you want, naming the merchant if you have a preference:

"Order a Caesar salad and a sparkling water from Zuni on DoorDash."

From the CLI:

agent-cards buy "a Caesar salad and a sparkling water from Zuni on DoorDash"

Step 2: Let it build the cart and ask for details

The tool searches the merchant, assembles the cart, and asks for anything it needs — most often the delivery address. It then shows you the cart and the total and waits. Nothing is charged yet. You can keep editing in plain language:

"Deliver to 123 Main St, and add a side of fries."

Step 3: Confirm to check out

Checkout — which charges a one-time virtual card — happens only after you explicitly confirm. The agent relays your confirmation on the same conversation, places the order, and reports back:

"Looks good — place the order."

The order is paid by a virtual debit card funded for that purchase, so the merchant only ever sees a single-use number with a hard limit — never your real card. If something about the total looks off, the limit protects you: the card declines rather than letting the charge run over.

Why a virtual card is the right payment method here

  • Hard ceiling per order. The card is funded with a fixed amount, so a bad cart or a runaway loop cannot overspend. See When AI Agents Overspend.
  • Explicit confirmation. The agent shops freely but cannot check out until you say so.
  • Per-purchase isolation. Each checkout uses its own card, so a single number leaking does not expose anything else.

Next steps