ERC-8004 and AI Agent Identity: Who Published This Agent?

Anyone can say they’re an AI agent

IN SHORT Websites now meet AI agents acting for people. Anyone can claim to be one, so a site needs a way to check who sent it.

On 22 September, Bloomberg reported that Amazon had blocked Meta’s new Muse agent from its retail site. Meta had declined a request to remove it. An Amazon spokesperson said third-party apps that buy on customers’ behalf:

On 1 October, The Paypers reported that Mastercard has started US testing of a probability score: how likely it is that an AI agent initiated a transaction. That’s an estimate, not a declaration you can check.

If you’re the API, the merchant or the platform on the receiving end, I’d check agent identityAgent identity Here: proof of who published an agent. It is not proof that the agent may act, or that the caller in front of you is that agent. See the glossary first: who published the agent. That’s one question out of several.

?Coming up next: So what can an agent actually show you?

IN SHORT You get two documents from two open specs, and they answer different questions, so I check both.

The A2A (Agent2Agent) protocol is an open standard for agents to talk to each other. It requires every A2A server to publish an Agent CardAgent Card A small JSON file (structured text a program can read) in which an agent describes itself: name, skills, address, and how to connect. See the glossary, and lets the server sign it.

ERC-8004, “Trustless Agents”, is a Draft ERC (a proposed Ethereum standard). It gives the agent an ERC-8004 entryERC-8004 entry A record in an on-chain registry, defined by the ERC-8004 Draft: a unique, transferable ERC-721 token with an owner and a link to a file. See the glossary in an on-chain registry: a handle with an owner, while the card says what the agent offers.

ADAM

ADAM says: Think of a business card checked against a company register. A register is usually kept by a body that checks filings; anyone can create an ERC-8004 entry, it changes owner like any token, and neither proves the bearer may sign.

Think of a business card checked against a company register. A register is usually kept by a body that checks filings; anyone can create an ERC-8004 entry, it changes owner like any token, and neither proves the bearer may sign.

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?Coming up next: Say both documents check out. What do you know then?

IN SHORT No: a registration shows who published an agent, not that it may act or that it works as advertised.

The Draft is direct about the ceiling. It “cryptographically ensures the registration file corresponds to the on-chain agent.” But it “cannot cryptographically guarantee that advertised capabilities are functional and non-malicious.”

For that, it points to its trust models: reputation, validation and TEE attestation.

IN PLAIN WORDS

Identity answers “who published this agent?”. The right to act comes from a mandate: who delegated, for what scope, up to what cap, until when.

Mandates are covered in the Know Your Agent episode on mandates. Whether a payment came from an agent at all is in the x402 data episode.

ITEM GET

Identity is not permission

A verified card and entry name the publisher. Check the mandate and the live caller separately.

Where I stand: I’m a named author of ERC-3643 and a co-author of ERC-8203, still a Draft in open PR #1614, not merged. I didn’t write ERC-8004 or A2A. This is the checklist I’d apply, read from the specs as published on 7 October 2026, not a report on a deployment of mine.

Sources, re-read on 7 October 2026: Bloomberg via The Star, The Paypers, ERC-8004 (Draft), ERC-8004 discussion, A2A specification v1.0.1. Not legal advice.