ERC-8004 for Agents

ERC-8004 defines a trust layer for agent ecosystems using three registries:

• Identity Registry for agent discovery and ownership
• Reputation Registry for feedback and scoring signals
• Validation Registry for third-party verification workflows

This page focuses on how GOAT Network builders should integrate the standard.

Contract Deployments on GOAT Network

The canonical erc-8004-contracts repository uses deterministic deployment. GOAT Network is included in the official mainnet deployment set:

Builder Flow

1) Construct the registry identifier for GOAT Network

Use the Identity Registry address and GOAT Network chain ID to construct the agentRegistry identifier:

• eip155:{chainId}:{identityRegistryAddress}

On GOAT Network mainnet (chain ID 2345):

• eip155:2345:0x8004A169FB4a3325136EB29fA0ceB6D2e539a432

2) Register the agent in Identity Registry

The canonical implementation supports three registration entry points:

• register()
• register(agentURI)
• register(agentURI, metadata)

Example using ethers.js on GOAT Network mainnet:

import { ethers } from 'ethers';
 
const IDENTITY_REGISTRY = '0x8004A169FB4a3325136EB29fA0ceB6D2e539a432';
const IDENTITY_ABI = [
  'function register(string agentURI) external returns (uint256)',
  'function setAgentWallet(uint256 agentId, address newWallet, uint256 deadline, bytes signature) external',
  'function setMetadata(uint256 agentId, string key, bytes value) external'
];
 
const provider = new ethers.JsonRpcProvider('https://rpc.goat.network');
const signer = new ethers.Wallet(process.env.PRIVATE_KEY, provider);
const registry = new ethers.Contract(IDENTITY_REGISTRY, IDENTITY_ABI, signer);
 
// Register with a URI pointing to the registration JSON
const tx = await registry.register('ipfs://QmYourRegistrationJSON');
const receipt = await tx.wait();
console.log('Agent registered, tx:', receipt.hash);

Useful follow-up methods include:

• setAgentURI(agentId, newURI)
• getMetadata(agentId, metadataKey)
• setMetadata(agentId, metadataKey, metadataValue) — metadataValue is bytes
• getAgentWallet(agentId)
• setAgentWallet(agentId, newWallet, deadline, signature)
• unsetAgentWallet(agentId)
• isAuthorizedOrOwner(spender, agentId)

agentURI should resolve to a registration JSON document, typically over IPFS or HTTPS.

3) Publish a registration JSON that matches the spec

The agentURI set during registration points to an off-chain JSON document (hosted on IPFS or HTTPS). This is not stored on-chain — only the URI is recorded in the contract. The following top-level fields are expected in this document per the ERC-8004 spec:

• type
• name
• description
• image
• services — each entry contains name, endpoint, version, and optionally skills and domains
• x402Support — boolean indicating payment capability via x402
• active
• registrations

supportedTrust is optional.

4) Collect trust signals through Reputation Registry

Write paths:

• giveFeedback(agentId, value, valueDecimals, tag1, tag2, endpoint, feedbackURI, feedbackHash)
• revokeFeedback(agentId, feedbackIndex)
• appendResponse(agentId, clientAddress, feedbackIndex, responseURI, responseHash)

Read paths:

• readFeedback(agentId, clientAddress, feedbackIndex)
• readAllFeedback(agentId, clientAddresses, tag1, tag2, includeRevoked)
• getSummary(agentId, clientAddresses, tag1, tag2)
• getLastIndex(agentId, clientAddress)
• getResponseCount(agentId, clientAddress, feedbackIndex, responders)
• getClients(agentId)

For production integrations, keep the on-chain record compact and store richer evidence off-chain behind feedbackURI, with feedbackHash when you need integrity verification.

5) Combine ERC-8004 with payment rails when needed

ERC-8004 is a trust and discovery layer. If your agent also charges for access, combine it with a payment protocol such as x402 rather than treating ERC-8004 itself as the payment layer. See the x402 Payments on GOAT Network guide for integration details.

Registration JSON Example

{
  "type": "https://eips.ethereum.org/EIPS/eip-8004#registration-v1",
  "name": "GoatAgent",
  "description": "Autonomous service agent on GOAT Network",
  "image": "https://example.com/agent.png",
  "services": [
    {
      "name": "A2A",
      "endpoint": "https://agent.example/.well-known/agent-card.json",
      "version": "0.3.0"
    },
    {
      "name": "MCP",
      "endpoint": "https://mcp.agent.example/",
      "version": "2025-06-18"
    },
    {
      "name": "x402",
      "endpoint": "https://agent.example/api/x402/orders",
      "version": "1.0.0"
    }
  ],
  "x402Support": true,
  "active": true,
  "registrations": [
    {
      "agentRegistry": "eip155:2345:0x8004A169FB4a3325136EB29fA0ceB6D2e539a432",
      "agentId": 1
    }
  ],
  "supportedTrust": ["reputation", "crypto-economic", "tee-attestation"]
}

If you are using ERC-8004 only for discovery, you can omit supportedTrust or leave it empty. Set x402Support to reflect your real payment capabilities rather than treating it as a decorative field. When x402Support is true, include a corresponding x402 service entry in services so that callers can locate the payment endpoint.

Operational Recommendations

1. Treat registration as discoverability, not automatic trust.
2. Pin the registration JSON and any feedback evidence to stable storage such as IPFS when possible.
3. Use feedbackURI + feedbackHash for auditable off-chain evidence.
4. Set a verified agent receiving wallet with setAgentWallet(...) when payments should not go to the owner address.
5. Verify on-chain state via the GOAT Network Explorer (opens in a new tab) after registration and wallet updates to confirm transactions landed correctly.

References

1. ERC-8004 page (Ethereum EIPs): https://eips.ethereum.org/EIPS/eip-8004 (opens in a new tab)
2. Canonical ERC markdown: https://raw.githubusercontent.com/ethereum/ERCs/master/ERCS/erc-8004.md (opens in a new tab)
3. ERC-8004 contracts repository: https://github.com/erc-8004/erc-8004-contracts (opens in a new tab)
4. ERC-8004 contracts README: https://raw.githubusercontent.com/erc-8004/erc-8004-contracts/main/README.md (opens in a new tab)
5. ERC-8004 spec file: https://github.com/erc-8004/erc-8004-contracts/blob/main/ERC8004SPEC.md (opens in a new tab)
6. ERC-8004 ABIs directory: https://github.com/erc-8004/erc-8004-contracts/tree/main/abis (opens in a new tab)
7. GOAT Network IdentityRegistry explorer page: https://explorer.goat.network/address/0x8004A169FB4a3325136EB29fA0ceB6D2e539a432 (opens in a new tab)
8. GOAT Network ReputationRegistry explorer page: https://explorer.goat.network/address/0x8004BAa17C55a88189AE136b182e5fdA19dE9b63 (opens in a new tab)
9. GOAT Network x402 repository: https://github.com/GOATNetwork/x402 (opens in a new tab)