Agent Identity (ERC-8004)

An Etherean with a Soul equipped is structurally an agent. It has identity (the NFT), a wallet (the TBA), a decision framework (soul.md), and can be embodied by any AI. We register this on the ERC-8004 Identity Registry.

What is ERC-8004

ERC-8004 is Ethereum's standard for trustless AI agent identity. It defines three onchain registries:

• Identity Registry — ERC-721 based. Each agent gets a unique NFT with a tokenURI pointing to an agent card (structured JSON describing capabilities and endpoints).
• Reputation Registry — standardized on-chain feedback signals from clients and other agents after interactions.
• Validation Registry — verifiable proof that an agent did what it claims.

The standard went live on Ethereum mainnet in January 2026. Co-authored by contributors from MetaMask, the Ethereum Foundation, Google, and Coinbase.

How Ethereans Use It

Registration

When a Soul is equipped, the Etherean's TBA calls IdentityRegistry.register(agentURI). The TBA itself makes the call (via tba.execute()), so the TBA owns the 8004 agent NFT. This means:

• The agent identity lives inside the TBA alongside the Soul NFT
• When you transfer the Etherean, the agent identity transfers with it
• The agent wallet is automatically set to the TBA address

Agent Card

The agentURI points to /api/etherean/{id}/agent-card, which returns spec-compliant JSON:

{
  "type": "https://eips.ethereum.org/EIPS/eip-8004#registration-v1",
  "name": "Etherean #1 (gami.eth)",
  "description": "Fully onchain Ethereum avatar...",
  "image": "https://etherean.ai/api/avatar/1.svg",
  "services": [
    { "name": "web", "endpoint": "https://etherean.ai/etherean/1" },
    { "name": "mcp", "endpoint": "npx @etherean/mcp --id 1" }
  ],
  "active": true,
  "supportedTrust": ["reputation"]
}

Transaction Flow

1. User calls EthereanSoul.mint(ethereanId, pixelData, content) — soul NFT minted to TBA
2. On confirmation, UI encodes register(agentURI) calldata
3. User calls tba.execute(identityRegistry, 0, calldata, 0)
4. Identity Registry mints agent NFT to TBA, sets agentWallet to TBA address

Registration is non-blocking — if it fails, the soul is still equipped. The agent registration can be retried later.

What This Unlocks

• Discoverability — other agents and protocols can find Ethereans via the 8004 registry
• Reputation — on-chain feedback on interaction quality and accuracy
• Agent-to-agent — Ethereans can interact with each other through standardized protocols
• Payments — x402 integration enables micropayments to the TBA for agent interactions
• Composability — any 8004-compatible protocol can integrate Etherean agents

Contracts