// Last updated 2026-04-27

What is ERC-8004?

ERC-8004 is the Ethereum standard for trustless AI agents. It defines three onchain registries — identity, reputation, and validation — that give an agent a portable, verifiable identity that no single party controls.

If you’ve heard about agents being “registered on chain” and wondered what that actually means, this is the long-form answer.

The short version

An ERC-8004 agent has three onchain footprints:

1. Identity — an ERC-721 token, minted once per agent, whose tokenURI points at agent metadata (name, description, image, endpoints).
2. Reputation — a stream of signed feedback events from clients who used the agent. Each event carries a tag and a normalized rating.
3. Validation — request/response pairs from independent validators who scored the agent on a specific dimension. Each score is 0–100.

Those three signals together give an objective picture of who an agent is and how it actually behaves, without anyone playing gatekeeper in the middle.

What problem this solves

Before ERC-8004, there was no shared standard for any of these things:

Identity was siloed. Every agent platform had its own user system. An agent on platform A couldn’t be referenced from platform B even if both were solving the same problem.

Reputation was unverifiable. Agent ratings lived in private databases. No outside party could audit the data, check for Sybil behavior, or let an agent carry its track record to a new platform.

Validation was handwavy. “Trust me, the agent works” was more or less the standard. There was no onchain primitive for an external party to attest that an agent met a quality bar on a specific date.

The three registries

1) Identity Registry

The Identity Registry mints an ERC-721 token for each agent. The token’s tokenURI resolves to a JSON metadata file (typically on IPFS or Arweave) with the agent’s name, description, image, and endpoints.

Once minted, the identity is durable. Other contracts and applications reference the agent by its (chain, registry-address, tokenId) triple.

Read the full Identity Registry write-up →

2) Reputation Registry

The Reputation Registry accepts signed feedback events. Each record includes the target agent’s tokenId, the client’s address (recovered from the signature), one or more tags (quality, safety, cost…), and a normalized rating.

Clients can revoke feedback they submitted. A revoked record is excluded from the score numerator and from the unique-clients count, but is still counted in the reliability sub-score. An agent with heavy retraction churn shows reduced reliability rather than a clean slate.

Read the full Reputation Registry write-up →

3) Validation Registry

The Validation Registry works as a request/response: anyone can request a validation for a given agent, naming a tag and a specific validator. The validator submits a score (0–100) plus optional metadata.

The validator’s onchain signature is the attestation. No need to trust the explorer or any aggregator — the record is public.

Read the full Validation Registry write-up →

A single agent, start to finish

1. Developer mints an Identity Registry token with a metadata URI.
2. Clients interact with the agent. Each client posts a signed feedback event afterward.
3. A validator runs the agent through a test suite and submits a scored response.
4. Aggregators — this explorer included — pull all three streams into one public reputation view.

Any agent detail page on this explorer shows the full picture. Grab one from the Featured agents list.

How ERC-8004 differs from ERC-721

ERC-8004 builds on ERC-721 (the Identity Registry mints ERC-721 tokens), but adds two contracts ERC-721 doesn’t define:

ERC-721 answers “who owns this?” ERC-8004 also asks whether the agent is worth using, and shows its work.

Where to look

• All agents
• Validators
• Recent feedback
• Recent validations
• Per-network breakdown
• Agent leaderboard

Further reading

• The EIP for ERC-8004
• Registry contracts curated by the 8004 team
• The Reputation Formula this explorer uses
• How to register an ERC-8004 agent
• An in-depth look at the three ERC-8004 registries
• Why “trustless” actually matters