What Is ERC-8004?
ERC-8004 is an Ethereum-compatible token standard, in active draft as of 2026, for agent-to-agent attestation: cryptographically signed claims that an AI agent did or saw a specific thing. Where ERC-20 standardised fungible tokens and ERC-721 standardised non-fungible tokens, ERC-8004 is the standardisation layer for agent-issued attestations that other agents and contracts can trustlessly verify.
The standard emerged from the convergence of two trends: the explosion of agent-to-agent commerce (AI agents transacting with other AI agents on behalf of their human principals), and the need for a verifiable record of what each agent did, saw, or paid for, in a way that does not depend on a central trusted intermediary. ERC-8004 provides the on-chain primitive: a structured, signed attestation that any other agent or contract can read.
Why ERC-8004 Matters for Content Monetization
The connection to content monetization runs through citation verification. When an AI agent cites a specific source in a generated answer, and that citation triggers a Pay-Per-Crawl-style payment, three parties need to trust the attestation: the publisher (was my content actually cited), the AI lab (did my agent actually generate this answer), and the marketplace (did this transaction actually happen). ERC-8004 attestations let all three verify the claim independently, without trusting a single point of failure.
The same primitive supports the next generation of agent-to-agent commerce flows. An agent buying access to another agent's output (a specialised expert agent, for example) needs to attest to what was bought, what was paid, and what was returned. ERC-8004 generalises this so the attestation format is the same across agents from different vendors, runtimes, and chains.
How ERC-8004 Works
An ERC-8004 attestation is a signed message conforming to the standard's schema, issued by an agent identified by an on-chain identity (typically a wallet address controlled by the agent or its operator). The message body contains the claim being attested (what was seen, done, or paid for), context (when, where, in response to what), and an optional reference to additional evidence stored on-chain or in a verifiable off-chain store.
The attestation is countersigned or verified by the relevant counterparty (publisher, marketplace, paying agent) to produce a complete record. Both signatures, plus any referenced evidence, become a verifiable on-chain or hybrid record that any third party can audit. The standard itself does not specify storage location (chain or off-chain), only the attestation schema and signature semantics.
In Practice
As of April 2026, ERC-8004 is in active draft and not yet finalised. Reference implementations exist on Ethereum mainnet and several L2s (Base, Optimism, Arbitrum). The Coinbase x402 ecosystem is the most active early adopter, with attestation flows tied directly to x402 payment events. Other agent platforms (Anthropic's Computer Use, OpenAI's Operator) do not yet emit ERC-8004 attestations natively but are being targeted by integrations.
For publishers and brands, the practical implication is that ERC-8004 is one of the standards that the citation-verified payment layer will run on. Pay-Per-Crawl, x402, and the various agent payment rails all benefit from a shared attestation primitive that lets each transaction be independently audited. ERC-8004 is not the only such primitive in the standards ecosystem (W3C Verifiable Credentials and IETF SCITT also play in this space) but it is the one most tightly integrated with the on-chain agent commerce flows that have emerged in 2025-2026.
Commonly Confused With
ERC-8004 is not a payment standard. It expresses what was done, not what was paid. Payment standards (x402, MPP, AP2, TAP) settle the money; ERC-8004 attests the action that justified the money. The two layers compose: an x402 payment plus an ERC-8004 attestation creates a fully verifiable payment-with-justification record.
