ERC-8004: Agent Trust Protocol

ERC-8004 establishes trust infrastructure for autonomous AI agents, enabling them to discover, identify, and evaluate other agents across organizational boundaries.

When to Use

• Registering an AI agent's identity on-chain
• Building reputation systems for AI agents
• Verifying agent identity before interactions
• Querying agent reputation and feedback
• Implementing trust-based agent interactions

Core Concepts

The Three Registries

Registry	Purpose	Key Functions
Identity Registry	Agent discovery via ERC-721 NFTs	register(), agentURI()
Reputation Registry	Feedback and attestations	giveFeedback(), getSummary()
Validation Registry	Verification hooks	Custom validators

Protocol Stack Position

Application Layer (Agent Apps, Marketplaces)
    ↓
Trust Layer (ERC-8004) ← This skill
    ↓
Payment Layer (x402)
    ↓
Communication Layer (A2A, MCP)

Installation

# JavaScript/TypeScript
npm install @chaoschain/sdk

# Python
pip install chaoschain-sdk

Contract Addresses

Celo Mainnet

Contract	Address
Identity Registry	Coming Soon (Q1 2026)
Reputation Registry	Coming Soon (Q1 2026)

Celo Sepolia (Testnet)

Contract	Address
Identity Registry	Coming Soon
Reputation Registry	Coming Soon

Agent Registration

1. Create Registration File

Create an agent registration file describing endpoints and capabilities:

{
  "type": "Agent",
  "name": "My AI Agent",
  "description": "Description of capabilities",
  "image": "ipfs://Qm...",
  "endpoints": [
    {
      "type": "a2a",
      "url": "https://example.com/.well-known/agent.json"
    },
    {
      "type": "mcp",
      "url": "https://example.com/mcp"
    },
    {
      "type": "wallet",
      "address": "0x...",
      "chainId": 42220
    }
  ],
  "supportedTrust": ["reputation", "validation", "tee"]
}

2. Upload to IPFS

import { upload } from "@chaoschain/sdk";

const agentMetadata = {
  type: "Agent",
  name: "My AI Agent",
  description: "AI agent for DeFi operations",
  // ...
};

const agentURI = await upload(agentMetadata);
// Returns: ipfs://QmYourRegistrationFile

3. Register Agent

import { IdentityRegistry } from '@chaoschain/sdk';
import { createPublicClient, http } from 'viem';
import { celo } from 'viem/chains';

const client = createPublicClient({
  chain: celo,
  transport: http('https://forno.celo.org'),
});

const registry = new IdentityRegistry(client);

// Register and get agent ID
const tx = await registry.register(agentURI);
const agentId = tx.events.Transfer.returnValues.tokenId;

console.log('Agent registered with ID:', agentId);

Reputation System

Give Feedback

import { ReputationRegistry } from '@chaoschain/sdk';

const reputation = new ReputationRegistry(client);

await reputation.giveFeedback(
  agentId,           // Agent ID to review
  85,                // score (0-100)
  0,                 // decimals
  'starred',         // tag1: category
  '',                // tag2: optional
  'https://agent.example.com',  // endpoint used
  'ipfs://QmDetailedFeedback',  // detailed feedback URI
  feedbackHash       // keccak256 of feedback content
);

Common Feedback Tags

Tag	Measures	Example
starred	Quality rating (0-100)	87/100
uptime	Endpoint uptime %	99.77%
successRate	Task success rate %	89%
responseTime	Response time (ms)	560ms
reachable	Endpoint reachable	true/false

Query Reputation

// Get all feedback for an agent
const feedback = await reputation.readAllFeedback(agentId);

// Get aggregated summary
const summary = await reputation.getSummary(agentId);
console.log('Average rating:', summary.averageScore);
console.log('Total reviews:', summary.totalFeedback);

Trust Verification Workflow

import { IdentityRegistry, ReputationRegistry } from '@chaoschain/sdk';

async function verifyAndInteract(targetAgentId, minReputation = 70) {
  // 1. Verify identity
  const identity = await identityRegistry.getAgent(targetAgentId);
  if (!identity) {
    throw new Error('Agent not registered');
  }

  // 2. Check reputation
  const summary = await reputationRegistry.getSummary(targetAgentId);
  if (summary.averageScore < minReputation) {
    throw new Error(`Agent reputation ${summary.averageScore} below threshold ${minReputation}`);
  }

  // 3. Get endpoint
  const agentData = await fetch(identity.agentURI).then(r => r.json());
  const endpoint = agentData.endpoints.find(e => e.type === 'a2a');

  // 4. Interact with verified agent
  const result = await interactWithAgent(endpoint.url);

  // 5. Submit feedback
  await reputationRegistry.giveFeedback(
    targetAgentId,
    result.success ? 90 : 30,
    0,
    result.success ? 'starred' : 'failed',
    '',
    endpoint.url,
    '',
    ''
  );

  return result;
}

Integration with x402 Payments

ERC-8004 and x402 work together for trustworthy paid agent interactions:

import { IdentityRegistry, ReputationRegistry } from '@chaoschain/sdk';
import { wrapFetchWithPayment } from 'thirdweb/x402';

async function payTrustedAgent(agentId, serviceUrl) {
  // 1. Verify trust
  const summary = await reputationRegistry.getSummary(agentId);
  if (summary.averageScore < 80) {
    throw new Error('Agent not trusted enough for payment');
  }

  // 2. Make paid request
  const fetchWithPayment = wrapFetchWithPayment({
    client,
    account,
    paymentOptions: { maxValue: "1000000" },
  });

  const response = await fetchWithPayment(serviceUrl);
  return response.json();
}

Use Cases

DeFi Trading Agents

Verify strategy agents before delegating funds:

const strategyAgents = await identityRegistry.searchByCapability('defi-trading');
const trustedAgents = [];

for (const agent of strategyAgents) {
  const summary = await reputationRegistry.getSummary(agent.id);
  if (summary.averageScore >= 85 && summary.totalFeedback >= 100) {
    trustedAgents.push(agent);
  }
}

Multi-Agent Workflows

Coordinate trusted agents for complex tasks:

const workflow = {
  research: await findTrustedAgent('research', 80),
  analysis: await findTrustedAgent('analysis', 85),
  execution: await findTrustedAgent('execution', 90),
};

// Execute with trust-verified agents
await executeWorkflow(workflow);

Validation Registry

For high-stakes operations, use Validation Registry for additional verification:

Model	Mechanism	Best For
Reputation-based	Client feedback	Low-stake, frequent
Crypto-economic	Stake + slashing	Medium-stake financial
zkML	Zero-knowledge proofs	Privacy-preserving
TEE Attestation	Hardware isolation	High-assurance

Celo Network Reference

Network	Chain ID	RPC Endpoint
Celo Mainnet	42220	https://forno.celo.org
Celo Sepolia	11142220	https://forno.celo-sepolia.celo-testnet.org

Additional Resources

• EIP Specification
• Official Website
• Learning Portal
• Contracts Repository
• Builder Program

Related Skills

• x402 - Payment layer for AI agents
• celo-rpc - Celo blockchain interaction
• viem - TypeScript Ethereum library