Inside AMEX’s agentic commerce stack: How intent contracts and single-use tokens enforce AI transactions

American Express (Amex) is building a system that lets AI agents shop and pay on behalf of users — but right now it’s only within its own payment network, and still involves a black box that could hinder trust and auditability.

Amex already participates in agentic commerce protocol projects, especially Google’s Agent Pay Protocol (AP2), which focuses on interoperability. Amex’s Agentic Commerce Experiences (ACE) developer kit, on the other hand, touches on something most protocols currently lack: Full transaction control in the payment layer. 

But it still isn't completely transparent in how it handles validation. ACE uses a closed-loop system — serving as both the card issuer and the payment network — to validate agent-led transactions. 

Luke Gebb, Amex's EVP and global head of innovation, told VentureBeat that the company believes this model is the missing piece in agentic commerce.  

“Some of what is missing so far is the perspective of a company like ours: We feel that trust and security are critical to advancing this space,” Gebb said. “This is really the first time that an issuer is coming to the table.”

Amex sits in that interesting space: Unlike other financial institutions or card providers like Chase or Bank of America, Amex can route transactions through its American Express Network. Visa and Mastercard are two of the most well-known payment networks, but these companies don’t issue cards themselves and must work with a bank.

The continued black box of agentic commerce 

The ACE kit is just one approach to addressing some of agentic commerce’s biggest problems: trust, control, accountability, validation, and security. 

Consumers generally don’t want rogue agents to run away with their bank accounts and start buying things. Merchants don’t want to be stuck with unpaid items. Banks don’t want to deal with an influx of chargebacks and the potential for fraud. 

Projects like the ACE kit aim to build trust and accountability by verifying an agent’s identity and goals. This can build the trust agentic commerce desperately needs.

Amex claims it offers validation, too, although the process behind that is unclear. It is abstracting how it performs validation, even though it explains at which layer it does it. More traditional systems feature a mix of deterministic checks and a flexible, semantic evaluation that helps match intent and outcome for validation. Amex said agents built with ACE can submit user shopping carts and check them against the agent's original intent. However, they did not disclose how this works.

Practitioners building to the agentic commerce ecosystem lament that, despite strides in creating a trust layer, many black boxes remain that could hinder widespread adoption.

Raj Ananthanpillai, founder and CEO of identity and verification system provider Trua, told VentureBeat that payment protocols and software kits like Agentic Commerce Suite from Stripe, Google's Verifiable Intent proof chain, and the ACE developer kit "excel at handling proofs, verifiable authorizations and the mechanics of fund movement, but leave upstream human validation opaque and underdeveloped."

Ananthanpillai continued: "Without a clear, high-assurance cryptographic link proving that an agent is acting under the explicit authority of a verified human owner, merchants, issuers, and networks face heightened risks of repudiation, massive chargebacks, sanctioned people conducting financial transactions, and fraud."

The ACE kit

The ACE developer kit solves several running issues with agentic commerce, Gebb said, and gives developers access to integrated services:

• Agent registration

• Account enablement

• Intent intelligence

• Payment credentials 

• Cart context

First, it deals with agent registration, establishing identity and trust with both the consumer and company agents. When a transaction begins, the agent acting on behalf of the customer and the merchant’s agent can verify each other’s identities and trust that they are dealing with the correct entity. 

Next comes account enablement, which links the user’s Amex account to their agent and grants the agent permission to act, or, in the case of agentic commerce, buy something.

Intent intelligence creates what Amex calls an intent contract, where the user defines what they want the agent to do. Once the intent is defined, the ACE system generates an Intent ID and a Proof of Intent Token that definitively proves authorization in the event of a dispute.

Amex handles the actual transaction part, where the user pays for the product through a single-use token. ACE establishes payment credentials used for the transaction, bound to intent and constraints. 

“Once the agent has found the item that the customer has asked for, like red shoes, they'll make a call for the payment credentials, which is a token that has the boundaries that the card member has provided,” Gebb said. “So, for instance, if they said they only wanted to spend $500, that token won't allow for a purchase of $600 because it has controls built in.”

The last piece is cart context and validation, which Gebb said helps banks and brands compare a user’s cart that their agent submitted to their intent. 

Amex’s approach shows that for agentic commerce to really soar, providers must understand what systems will allow agents to do and who is ultimately accountable if something goes wrong.