---
title: "Recheck prices and stock when the order is · Agent Wranglers"
url: https://agentwranglers.se/playbook/ecommerce/carts-and-checkout/recheck-at-checkout
id: ECM-13
level: Recommended
updated: 2026-10-22
tokens: 907
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Recheck prices and stock when the order is placed

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Carts and checkout](https://agentwranglers.se/playbook/ecommerce/carts-and-checkout.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22.

- ID: ECM-13
- Level: Recommended
- Chapter: [Carts and checkout](https://agentwranglers.se/playbook/ecommerce/carts-and-checkout.md)
- Rule: When the buyer places the order, recompute every price, discount, shipping cost and tax on the server and check stock again. If the total differs from what the buyer saw, show the new total and ask again before charging.
- Check: A test raises a price after the cart was shown and then places the order. No payment is created, and the answer carries the new total. A second request with the new total succeeds.
- How: A cart can sit for days while prices, stock and coupons change. Never charge a total the buyer did not see, and never honour a stale lower price by accident. Keep only variant IDs, quantities and codes in the cart, and compute amounts from the catalogue, as [Work out every amount on the server](https://agentwranglers.se/playbook/adversarial-testing/abuse-and-limits/server-side-business-rules.md) requires. Send the total the buyer saw with the order request, and refuse it when it differs from the fresh total. Once the order exists, freeze its lines as [Freeze what the customer agreed to on the order](https://agentwranglers.se/playbook/payments/amounts-and-orders/order-snapshot.md) says.

## Examples

**Using these examples:** they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

### TypeScript example

```ts
export async function placeOrder(cart: Cart, shownTotalMinor: number) {
  const quote = await priceCart(cart); // catalogue prices, discounts, shipping, tax
  if (quote.totalMinor !== shownTotalMinor) return { status: 'total_changed', quote };
  return { status: 'ok', order: await createOrder(cart, quote) };
}
```

### Python example

```python
def place_order(cart, shown_total_minor: int) -> dict:
    quote = price_cart(cart)
    if quote.total_minor != shown_total_minor:
        return {"status": "total_changed", "quote": quote}
    return {"status": "ok", "order": create_order(cart, quote)}
```

## Related rules

- SEC-59 [Work out every amount on the server](https://agentwranglers.se/playbook/adversarial-testing/abuse-and-limits/server-side-business-rules.md) in Adversarial testing
- PAY-12 [Freeze what the customer agreed to on the order](https://agentwranglers.se/playbook/payments/amounts-and-orders/order-snapshot.md) in Payments and billing

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/ecommerce/carts-and-checkout/recheck-at-checkout">Agent Wranglers e-commerce and fulfilment playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Merge the guest cart into the account cart on sign-in](https://agentwranglers.se/playbook/ecommerce/carts-and-checkout/cart-merge.md)
- Next: [Show delivery limits and payment methods when checkout starts](https://agentwranglers.se/playbook/ecommerce/carts-and-checkout/delivery-restrictions-upfront.md)
- [Carts and checkout](https://agentwranglers.se/playbook/ecommerce/carts-and-checkout.md)