AI PAYMENT THREAT · MERCHANT SUBSTITUTION
Prevent merchant substitution in agentic checkout
A valid product choice is not safe when the final checkout silently moves to a different seller.
Where the failure appears
Search manipulation, affiliate redirects, tool compromise or inventory changes can move an agent from an approved merchant to an unknown seller.
Who needs the control
Shopping agents, marketplaces, booking systems and merchants supporting cross-site autonomous checkout.
Execution-time response
- Represent merchants with stable identifiers, not display names.
- Store the approved merchant or narrow allowlist in the mandate.
- Bind the signed final payee during strict verification.
- Block mismatches; otherwise require provider-bound consumption and one fresh permit redemption before submission.
Relevant controls
Stable merchant IDsPayee bindingMerchant allowlistsRedirect-aware checkout factsIntent hashesEvidence receipts
What changes
The final payee must match the seller authority the customer actually granted.
Reproduce the failure safely
Change a sample amount, seller, consent field or instruction and inspect the structured decision before integrating.
Test the threat free →