---
title: "Price written in dollars where atomic units are required — x402 defect class amount-not-atomic"
description: "Price written in dollars where atomic units are required (amount-not-atomic), an x402 defect class: accepts amounts are integer atomic units (USDC has six decimals). Detectable by an unpaid probe. A decimal point usually means the price is off by a factor of a million, in one direction or the other."
canonical: "https://scvd.store/defects/amount-not-atomic"
url: "https://scvd.store/defects/amount-not-atomic"
term_code: "amount-not-atomic"
defined_in: "https://scvd.store/defects"
data: "https://scvd.store/defects.json"
vocabulary_version: "22"
license: "https://creativecommons.org/licenses/by/4.0/"
---

# Price written in dollars where atomic units are required

`amount-not-atomic` — an x402 defect class.

**Asserts:** accepts amounts are integer atomic units (USDC has six decimals).

**Costs:** A decimal point usually means the price is off by a factor of a million, in one direction or the other.

**Detectable:** unpaid — a free probe can see it

**Falsified by:** The amount parsing as an integer string.

**How an operator clears it:** Write amount as an integer string of atomic units — for USDC, dollars times ten to the sixth — and derive it from one constant so the menu and the challenge cannot disagree.

**What a buyer does:** Do not pay a decimal amount: the true price is off by a factor of a million in a direction you cannot know. Refuse, and if you must proceed, get the atomic integer from the operator in writing first.

**Our signal:** `amount-not-atomic`

---

Vocabulary v22, CC BY 4.0. Every class: https://scvd.store/defects. Machine-readable, with falsifiers and cross-instrument mappings: https://scvd.store/defects.json.

A class describes a property of one endpoint at one moment and never accumulates into a judgment on an operator.