How AI agents check out online
TL;DR. An AI agent can describe a product. It cannot finish a real purchase by reading a search result. Checkout lives inside a signed-in store account — the item, every charge, the total, the address, and the card the store will charge. Nook connects a person's store accounts so their agent can request that real checkout quote and place the order only after the person approves, in chat or with Buy on Nook's review page. Quotes and purchases work today at Amazon, Uber Eats, Instacart, Walmart, Target, and Chewy.
Why checkout is the hard part
Most of shopping looks easy to an agent. The last step is different. Every store has its own sign-in, cart, and final order button. Delivery, tax, tips, promotions, and the address the store selected all show up at checkout, so a product-page price is not always what the account will be charged. If an agent skips that page, it is guessing.
That is why "my agent bought it" is a specific claim: either the agent reached the store's real checkout in the person's account, or it did not.
Three ways people try to let an agent shop
When someone asks an agent to buy something, the integration usually falls into one of three patterns.
1. Shop from search results
The agent finds a listing and treats the listed price as the price. That is useful for discovery. It is not a checkout. Search results can omit shipping, bags, tips, or the seller the store will actually use. They also cannot confirm the saved address or card the store will charge.
2. Drive the store's website like a person
The agent, or a script behind it, opens a browser, signs in, and clicks through the cart. This can work on a good day. It is also brittle: stores change markup, show robot checks, and keep carts that already have other items in them. A missed click can order the wrong size or check out leftover items.
3. Ask the person for passwords or card numbers in chat
A person should not type a store password or a full card number to an agent, and the agent should not store those secrets in a chat log.
Nook is built as a fourth path: the person connects their store accounts once, the agent receives an authorized connection rather than credentials, and every purchase still needs the person's yes.
How approved real checkout works
Nook sits between the person, their agent, and the stores they already use.
- The person connects their accounts. They sign in to Nook with their phone at nookstore.xyz/v3/accounts and connect the stores they shop at. Their agent sends a connection link; the person claims it. The agent never sees what they type.
- The agent asks for a quote. It sends what the person asked for — the product in the product's own words, the quantity, and any address or payment the person named.
- Nook reads the store's own checkout. A fresh cloud browser restores the person's saved sign-in, finds the product, and reads the figures the store itself is showing: product, quantity, each charge, the total, the address, and the payment method. Then Nook puts the cart back as it was.
- The person reviews those figures. The agent should show the item, the charges, and the total — plus anything the person needs to know, such as the seller, delivery details, or a warning.
- The person approves. Their yes to that total, in their own words, is enough. If the agent does not have those words, the person approves with Buy on Nook's signed-in review page.
- Nook places the order once. It presses the store's final order button and checks for confirmation. The agent reports the order number back. The store also emails its own confirmation to the account.
The opening request — even one that says "order this" or "buy this" — is not the approval. The person has to say yes to the quoted total.
What a real quote contains
When Nook returns a ready quote, it is not summarizing a search page. It has read the store's checkout and reports:
- The product and quantity
- Each charge row the store showed, and the total those rows add up to
- The destination it matched, when an address was selected
- The payment method it matched — for example a card brand and last four digits
- Whether a requested tip matched, on stores that take a tip
- When the quote expires
- Any blocker, choice, or warning the agent must pass on
The agent should tell the person exactly what the quote says, and nothing it does not say. If the store needs a choice — a size, a menu option, pickup versus shipping — the agent asks instead of guessing. A quote can hold several products from one store; Nook adds them, reads checkout once, and puts the cart back.
What happens after the person says yes
Nook buys at the quoted total or less. Just before it places the order, it reads the store's checkout again. If the total went up, or the item, address, or card changed, it stops without buying. The agent should ask about a fresh quote instead of pushing through.
If Nook pressed the final button but cannot read the result, the purchase is uncertain: the order may exist. The agent should tell the person to check the store's order history. It should not buy the same quote again, and it should not claim that nothing was bought.
The person can cancel on the review page until Nook starts placing the order. Cancellation cannot undo an order the store has already accepted.
Which stores an agent can check out at today
Six stores can return a checkout quote and place the order when the person says yes:
- Amazon
- Uber Eats
- Instacart
- Walmart
- Target
- Chewy
Six more can be connected today but do not quote yet: DoorDash, Urban Outfitters, Resy, Detoure, Delta, and Apple. The account can be linked, but there is no checkout quote until that store supports one. Nook can also learn a new store from its web address; once a checkout is verified there, a connected account can quote one product at a time, shipped to the address that store selects.
For pickup versus shipping, tips, item limits, and what is not supported yet, see stores.md and Best stores for AI agent shopping.
What the agent never sees
The person signs in to their stores in Nook's own form. Saved store sessions are encrypted. Each connection is verified in a fresh cloud browser before it counts.
The agent receives a connection it can shop with. It does not receive the password, and it does not receive the browser session. The person can see and disconnect every connection on their accounts page.
A partner key identifies the agent to Nook. The agent keeps that key in its host's private storage. It should never show the key to the person or ask them for one.
A quote takes about a minute on Amazon, Instacart, Walmart, and Chewy, and two to three minutes on Uber Eats.
If you are the person using the agent
Connect the accounts you already have, then keep the final say. Ask your agent for a Nook link, sign in with your phone, and go back to the chat. When it shows a total, read it. If it is right, say yes — or tap Buy on the review page. Nothing is bought until you approve the quoted total.
A walkthrough for ChatGPT, Claude, or Cursor: Let ChatGPT, Claude, or Cursor buy — with your approval.
If you are building the agent
Nook gives agents one partner-key API for connection links, quotes, purchases, and preferences, as REST or as MCP tools at https://nookstore.xyz/mcp.
- Register a partner key, or use the one your developer configured.
- Send the person a connection link.
- Request a quote on a connection they granted you.
- Show them the item and the total.
- Buy only with their confirming words, or send them to the review page.
The short version lives in the quickstart. The exact fields, store limits, polling, and recovery steps live in the agent guide.
If you are choosing between Nook and a custom integration, read Nook vs building your own agent shopping integration.
Get started
If you want your agent to shop for you: connect your stores at nookstore.xyz/v3/accounts. Sign in with your phone.
If you are the agent, or you are building one: start with the quickstart or the full agent guide. Get a partner key, send a connection link, quote the store's own checkout, and buy only after the person says yes.
Nook is in private beta. Connecting accounts is free for buyers during the beta, and agents register a partner key for free. Safety, cancellation, and pricing questions are answered in the AI agent shopping FAQ and Nook's FAQ.