# ERC-8004 Trustless Agents

> 0G supports ERC-8004, the Trustless Agent standard, so agents on 0G are discoverable and interoperable. Includes registry addresses and 8004scan.


0G officially supports **ERC-8004**, the Trustless Agent standard. 0G's ERC-8004 registry deployment is listed in the official [`erc-8004-contracts`](https://github.com/erc-8004/erc-8004-contracts) repository, so agents on 0G can be **discovered**, **verified**, and **interoperate** across the broader ERC-8004 agent ecosystem.

:::tip Navigation Guide
- **This page**: 0G's ERC-8004 support, registry addresses, and agent discovery
- **[Agentic ID Overview](./overview)**: High-level Agentic ID concepts
- **[ERC-7857 Standard](./erc7857)**: The encrypted-ownership standard behind Agentic IDs
- **[Integration Guide](./integration)**: Step-by-step development guide
:::

## What Is ERC-8004?

**ERC-8004 ("Trustless Agents")** is an Ethereum standard that defines a lightweight set of on-chain registries so autonomous AI agents can be **discovered, identified, and trusted across organizational boundaries** — without any pre-existing trust or a centralized intermediary.

It gives every agent a portable, verifiable identity that any ecosystem tool can read, complementing agent-to-agent protocols (such as A2A and MCP) with an on-chain trust layer.

### The Registries

| Registry | Role |
|----------|------|
| **Identity Registry** | Assigns each agent a global `agentId` and points to its off-chain *agent card* (name, description, endpoints, capabilities). This is the core discoverability record. |
| **Reputation Registry** | Stores signed feedback so agents can accumulate portable, verifiable reputation. |
| **Validation Registry** | Optional, independent verification of agent behavior. Defined by the standard and still evolving. |

## 0G Support for ERC-8004

0G has deployed the ERC-8004 reference registries on 0G Chain, and 0G's deployment is listed in the canonical [`erc-8004-contracts`](https://github.com/erc-8004/erc-8004-contracts) repository. This gives 0G agents three things:

- **Discoverability** — an agent registered on 0G is visible to any ERC-8004-aware tool or indexer.
- **Interoperability** — 0G agents share the same identity and reputation graph as agents on other ERC-8004 chains.
- **Standard alignment** — 0G agents follow the same registration and agent-card model as the rest of the ecosystem.

### 0G Registry Addresses

The `agentId` space is a **global, shared counter** on the Identity Registry — it is not scoped per project or per app.

**0G Mainnet** (chain ID `16661`)

| Registry | Address |
|----------|---------|
| **Identity Registry** | [`0x8004A169FB4a3325136EB29fA0ceB6D2e539a432`](https://chainscan.0g.ai/address/0x8004A169FB4a3325136EB29fA0ceB6D2e539a432) |
| **Reputation Registry** | [`0x8004BAa17C55a88189AE136b182e5fdA19dE9b63`](https://chainscan.0g.ai/address/0x8004BAa17C55a88189AE136b182e5fdA19dE9b63) |

**0G Galileo Testnet** (chain ID `16602`)

| Registry | Address |
|----------|---------|
| **Identity Registry** | [`0x8004A818BFB912233c491871b3d84c89A494BD9e`](https://chainscan-galileo.0g.ai/address/0x8004A818BFB912233c491871b3d84c89A494BD9e) |
| **Reputation Registry** | [`0x8004B663056A597Dffe9eCcC1965A193B7388713`](https://chainscan-galileo.0g.ai/address/0x8004B663056A597Dffe9eCcC1965A193B7388713) |

## Discover Agents on 8004scan

[8004scan.io](https://8004scan.io) is an explorer for ERC-8004 agents. Once an agent is registered, it appears there — its `agentId`, chain, service endpoints, and reputation — alongside agents from across the ecosystem.

## Agentic ID and ERC-8004

[Agentic ID](/concepts/agentic-id) is 0G's agent-identity surface, and it is **ERC-8004 compatible**: an Agentic ID can carry a corresponding ERC-8004 registration, so an agent created on 0G is discoverable through the standard while its ownership and encrypted intelligence continue to be governed by [ERC-7857](./erc7857).

## Resources

- **ERC-8004 standard** — [EIP-8004](https://eips.ethereum.org/EIPS/eip-8004)
- **Reference contracts** — [`erc-8004/erc-8004-contracts`](https://github.com/erc-8004/erc-8004-contracts)
- **Agent explorer** — [8004scan.io](https://8004scan.io)
- **Related standard on 0G** — [ERC-7857](./erc7857) · [Agentic ID Overview](./overview)