Erc8004 Agent Identity

ERC-8004 — On-Chain AI Agent Identity

ERC-8004 is an open Ethereum standard for discovering, choosing, and interacting with AI agents across organizational boundaries without pre-existing trust. It was created by the Sperax team and is deployed across 12 chains.

Spec: https://eips.ethereum.org/EIPS/eip-8004

Why ERC-8004?

As AI agents proliferate, we need a way to:

• Discover agents across platforms (not locked in one vendor)
• Verify agent capabilities and track record
• Trust agents without knowing who built them
• Pay agents via standard protocols (x402, on-chain)

ERC-8004 solves this with three on-chain registries.

The Three Registries

1. Identity Registry (ERC-721 NFT)

Every agent gets an NFT identity — a unique, transferrable on-chain identity.

• Based on ERC-721 with URIStorage
• TokenURI points to a JSON registration file
• Owners can update metadata, transfer, or burn
• One NFT = one agent identity

2. Reputation Registry

A standard interface for posting and querying feedback signals about agents.

| Signal | Measures | Scale | |--------|----------|-------| | starred | Quality rating | 0–100 | | reachable | Endpoint reachable | binary | | uptime | Availability | percentage | | successRate | Task completion rate | percentage | | responseTime | Response latency | milliseconds | | tradingYield | Trading return | signed percentage | | revenues | Cumulative revenue | USD |

Star ratings map to the 0–100 scale:

• 1★ = 20, 2★ = 40, 3★ = 60, 4★ = 80, 5★ = 100

3. Validation Registry

Independent validator attestations for agent capabilities:

• zkML proofs (zero-knowledge machine learning)
• TEE attestations (trusted execution environment)
• Staker validations (economic security)
• Custom validator contracts

Agent Registration

Registration File Format

{
  "type": "https://eips.ethereum.org/EIPS/eip-8004#registration-v1",
  "name": "My Trading Agent",
  "description": "Automated yield optimizer on Arbitrum",
  "image": "https://cdn.example.com/agent-avatar.png",
  "services": [
    {
      "name": "MCP",
      "endpoint": "https://api.myagent.com/mcp",
      "version": "2025-06-18",
      "mcpTools": ["getQuote", "executeTrade"]
    },
    {
      "name": "A2A",
      "endpoint": "https://api.myagent.com/.well-known/agent-card.json",
      "version": "0.3.0",
      "a2aSkills": ["defi/yield_optimization"]
    },
    {
      "name": "ENS",
      "endpoint": "myagent.eth",
      "version": "v1"
    }
  ],
  "x402Support": true,
  "active": true
}

Service Types

| Service | Purpose | Use When | |---------|---------|----------| | MCP | Model Context Protocol | Agent exposes tools for other AI to call | | A2A | Agent-to-Agent | Agent participates in multi-agent workflows | | ENS | Ethereum Name Service | Human-readable agent address | | DID | Decentralized Identifier | Cross-chain identity |

Key Operations

| Operation | Description | |-----------|-------------| | registerAgent | Mint an agent NFT with metadata | | lookupAgent | Query agent details by token ID | | searchAgents | Find agents by criteria | | updateMetadata | Update agent's registration file | | transferAgent | Transfer ownership to new address | | getAgentReputation | Fetch reputation signals | | submitFeedback | Post a reputation signal | | addValidation | Add validator attestation | | getValidations | Query validations for an agent | | listAgents | List agents by owner |

Supported Chains (12)

| Chain | Networks | |-------|----------| | Ethereum | Mainnet, Sepolia | | BNB Chain | Mainnet, Testnet | | Arbitrum | Mainnet, Sepolia | | Base | Mainnet, Sepolia | | Optimism | Mainnet, Sepolia | | Polygon | Mainnet, Amoy |

All contracts use vanity addresses starting with 0x8004...

Best Practices

Registration

1. Always include a rich registration file with name, description, image, and services
2. Declare services explicitly — other agents need to know how to communicate
3. Keep metadata current — update when endpoints change
4. Use active flag — set "active": false when taking agent offline

Reputation

1. Encourage feedback — more signals = more trust
2. Monitor your scores — respond to quality issues
3. Use standard signal types — stick to the defined tags for interoperability
4. Trusted probers (infra watchtowers) should regularly publish uptime/reachability

Security

1. Validate callers — check msg.sender for sensitive operations
2. Rate-limit feedback — prevent spam signals
3. Verify validators — ensure validator contracts are trustworthy

Use Cases for OpenClaw Agents

Register Your OpenClaw Agent On-Chain

Give your agent a verifiable identity that works across platforms:

1. Deploy agent registration via ERC-8004
2. Advertise MCP endpoints so other agents can discover your tools
3. Build reputation over time as users interact

Discover & Interact With Other Agents

Use the ERC-8004 registries to:

1. Find specialized agents (e.g., "DeFi yield optimizer on Arbitrum")
2. Check reputation before trusting
3. Call via MCP or A2A protocols

Build Agent Marketplaces

ERC-8004 provides the infra layer for on-chain agent marketplaces:

• Identity (who is this agent?)
• Reputation (is it any good?)
• Validation (has it been audited?)
• Discovery (how do I find it?)

Related Resources

| Resource | URL | |----------|-----| | ERC-8004 Spec | https://eips.ethereum.org/EIPS/eip-8004 | | Best Practices | https://github.com/nirholas/best-practices | | Agent Creator UI | https://github.com/nirholas/erc8004-agent-creator | | Demo Agent | https://github.com/nirholas/erc-8004-demo-agent | | Solidity Contracts | https://github.com/nirholas/erc-8004-contracts | | Subgraph | https://github.com/nirholas/subgraph | | SperaxOS | https://sperax.io |

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Sperax
• Source: Sperax/sperax-skills
• License: MIT

Install and usage instructions live in the source repository linked above.