---
title: Know Your Human (KYH): Fraud prevention for agentic commerce
source_page: https://www.sardine.ai/blog/know-your-human-agentic-commerce
canonical: https://www.sardine.ai/blog/know-your-human-agentic-commerce
format: text/markdown
date: 2026-11-12T14:00:00.000Z
author: Soups Ranjan
description: AI shopping agents hide the device and IP merchants rely on, so good orders get declined. Sardine’s Know Your Human (KYH) binds human identity to agents.
---

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---

# Know Your Human (KYH): Fraud prevention for agentic commerce

**Author:** Soups Ranjan · **Published:** 2026-11-12T14:00:00.000Z · **Read time:** 4 · **Categories:** Fraud

AI shopping agents hide the device and IP merchants rely on, so good orders get declined. Sardine’s Know Your Human (KYH) binds human identity to agents.

Personal shopping agents like Instinct, Muse by Meta and Dots by OpenAI are gaining traction. For merchants, that creates two problems: legitimate purchases get declined because agents look like bots, and orders that do go through can lack the customer device signals needed to defend a chargeback.
Sardine’s Know Your Human (KYH) binds the customer’s own device to the agent’s session. Here’s why those signals matter and how merchants can use KYH to approve more legitimate purchases and strengthen their dispute responses.
Why agents convert poorly
Shopping agents often convert poorly because merchants mistake them for malicious bots and decline the order.
This happens because an agent typically shops through a cloud browser running in a data center, rather than on the customer’s phone or computer. When the agent goes to checkout, a merchant may see the session tied to a data center IP address and a headless browser controlled by software. These are signals you’ll often see during card testing or credential stuffing attacks, so most fraud tools will associate this with bot activity and flag it as high risk.
The merchant can identify automation, but has little information about the customer behind it. A legitimate agent buying on someone’s behalf can trigger the same controls used to block fraud.
Sardine’s Know Your Human (KYH) solution fixes this problem by capturing device and behavior signals from the customer’s own device and binding them to the agent’s session. That gives merchants the data they need to verify that a human behind the transaction is making a legitimate purchase, so they can approve more good orders.
Agent purchases also leave a gap in chargeback evidence
Approving the order is only part of the problem. A customer may not recognize a purchase their agent made, forget they requested it, or claim they never authorized it.
If the merchant recorded only the agent’s cloud device and IP address, it may struggle to connect the purchase to the customer’s previous activity. The missing signals matter because card network programs use device and identity data to help merchants defend against first-party fraud.
Visa Acquirer Monitoring Program
A legitimate agent purchase can still hurt the merchant’s standing under Visa’s Acquirer Monitoring Program (VAMP). If the customer reports it as unauthorized, the issuer may file both a fraud report (TC40) and a chargeback (TC15). Both can count toward the VAMP ratio, so one unrecognized purchase can hit the merchant twice.
VAMP ratio = (Fraud reports (TC40) + Disputes (TC15)) ÷ Settled transactions (TC05)
Without the customer’s device signals, the merchant may also lack the evidence needed for a qualifying CE 3.0 exclusion. Winning the chargeback alone does not automatically remove both records from VAMP.
Missing customer signals weaken dispute defenses
Without the customer’s device data, merchants may be unable to meet the evidence requirements for Visa’s Compelling Evidence 3.0 (CE 3.0) or Mastercard’s First-Party Trust program.
CE 3.0 requires at least two matching data elements across the disputed purchase and two qualifying prior undisputed transactions. At least one must be a device ID, fingerprint, or IP address match. Mastercard requires evidence across device, delivery, and identity factors, with an IP address, device ID, or fingerprint meeting the device requirement.
KYH strengthens the merchant’s dispute evidence
KYH records the customer’s device ID, fingerprint, and IP address against the agent’s session. These provide the device or IP match required for CE 3.0 when they match qualifying prior transactions, and can satisfy the device factor under Mastercard First-Party Trust.
How Know Your Human works
KYH is a lightweight way to bind a human to an agent’s session. It works like an OTP flow, except the merchant sends the customer a link instead of the one-time code itself. Opening that link lets Sardine capture signals from the customer’s own device before they pass the code to the agent.
See the verification flow in action:
The flow has three steps:
Send a verification link. The merchant sends a secure, short-lived link to the customer by SMS or email.
Collect device signals. The customer opens the link on their phone, loading a page with Sardine’s device and behavior SDK embedded. The SDK captures signals, including device ID, fingerprint, and IP address, and associates them with the session. The page then displays the one-time code.
Verify the code and assess the purchase. The customer enters the code into the shopping agent’s window, and the agent submits it at checkout. The merchant validates it, connecting the customer, their device, and the agent’s session. Those signals can then inform the fraud decision alongside account history and payment details.
KYH can also associate email and phone with the session. Agents can pass session details through a few additional HTTP headers, keeping the exchange lightweight and complementary to existing agentic commerce protocols.
Accept more legitimate agent purchases
Give your risk team the customer signals they need to approve legitimate agent purchases and support chargeback responses. Visit our website to learn more about Know Your Human, or schedule a call with our team to discuss how KYH would work in your checkout.