What is ERC-8004?

The Problem: AI Agents Need Identity

We are entering an era where billions of autonomous AI agents will operate on the internet — trading, negotiating, collaborating, and making decisions on behalf of humans and organizations. But how do these agents establish trust with each other?

Today, agent identity is fragmented. An agent might have an API key here, a certificate there, and a reputation on some centralized platform. None of these are portable, verifiable, or permanent. If the platform disappears, the agent's identity disappears with it.

ERC-8004 solves this by anchoring agent identity to Ethereum — the most battle-tested, censorship-resistant ledger in the world.

The Three Registries

ERC-8004 defines three lightweight on-chain registries that together provide a complete trust infrastructure for autonomous agents:

Who Created ERC-8004?

ERC-8004 was authored by a cross-organization team of senior engineers:

• Marco De Rossi — MetaMask
• Davide Crapis — Ethereum Foundation (dAI team)
• Jordan Ellis — Google
• Erik Reppel — Coinbase

The standard has received contributions from over 100 developers, including teams from ENS, EigenLayer, The Graph, and Taiko.

Where is ERC-8004 Deployed?

ERC-8004 uses CREATE2 for deterministic deployment, meaning the Identity Registry has the same contract address on every chain:

Identity Registry:   0x8004A169FB4a3325136EB29fA0ceB6D2e539a432
Reputation Registry: 0x8004BAa17C55a88189AE136b182e5fdA19dE9b63

Deployed and active on:

How Does It Work with A2A and MCP?

ERC-8004 is designed to complement existing AI agent protocols:

• Google A2A (Agent-to-Agent): Agents register their A2A service endpoints in their passport. Other agents discover them via the Identity Registry and connect directly.
• MCP (Model Context Protocol): MCP server URLs can be registered as service endpoints, enabling tool discovery through on-chain identity.
• x402 (Coinbase/Cloudflare): Payment protocol integration enables agent-to-agent commerce with automatic reputation feedback.

The key insight: A2A and MCP handle communication; ERC-8004 handles identity, trust, and accountability.

ERC-8183: Agentic Commerce Protocol

Published on March 10, 2026 by the Ethereum Foundation's dAI team and Virtuals Protocol, ERC-8183 is the commerce layer that complements ERC-8004. It defines a trustless escrow protocol for agent-to-agent jobs:

ERC-8183 deliberately omits reputation — that's ERC-8004's job. Instead, it uses a modular hook system to integrate with ERC-8004 reputation checks, KYC validation, or custom logic without modifying the core contract.

Authors: Davide Crapis (EF dAI), Bryan Lim, Tay Weixiong, Chooi Zuhwa (Virtuals Protocol)

x402: HTTP-Native Agent Payments

x402 revives the HTTP 402 “Payment Required” status code to enable instant stablecoin micropayments directly over HTTP. Developed by Coinbase and backed by Cloudflare, Circle, Stripe, and AWS, it lets agents pay for API calls, data access, and services without accounts or authentication flows.

// Agent requests a paid API
GET /api/premium-data HTTP/1.1

// Server responds with payment details
HTTP/1.1 402 Payment Required
X-Payment: {"amount": "0.001", "token": "USDC", "address": "0x..."}

// Agent pays and retries — access granted
GET /api/premium-data HTTP/1.1
X-Payment-Proof: {tx: "0x..."}

x402 is the payment rail; ERC-8004 is the trust rail. Together with ERC-8183 escrow, they form the complete commerce stack for autonomous agents. Transaction history from x402 feeds back into ERC-8004 reputation scores, creating accountability for every payment.

50M+ transactions processed · Backed by Coinbase, Cloudflare, Circle, Stripe, AWS

Risk-Proportional Trust

Not every interaction demands the same level of verification. ERC-8004's layered architecture supports risk-proportional trust:

How to Register Your Agent

The fastest way to get an ERC-8004 passport is through the Chitin Protocol, which adds permanent Arweave storage and a Soulbound Token on Base L2.

Option 1: SDK

npm install @chitin-id/sdk

import { register } from "@chitin-id/sdk";

const result = await register({
  apiUrl: "https://chitin.id",
  agentName: "my-agent",
  description: "My autonomous agent",
  capabilities: ["a2a", "mcp"],
});

Option 2: MCP Tool

npx chitin-mcp-server
# Then use register_soul tool from any AI assistant

Option 3: Web Interface

Visit chitin.id and follow the onboarding guide. No code required.

The Machine Economy

ERC-8004 is a foundational piece of the emerging machine economy. With 20,000+ agents already registered and 70+ projects building agent browsers and tools, it's rapidly becoming the default standard for AI agent identity on Ethereum.

The Ethereum Foundation's dAI (Decentralized AI) team has endorsed ERC-8004 as a core component of their 2026 roadmap, signaling that agent identity is becoming as fundamental to Web3 as wallet identity.