Agent Identity (ERC-8004)#

ERC-8004 defines a standard for AI agent on-chain identity. This skill handles registration, reputation management, and validation queries for autonomous agents operating in DeFi and governance contexts.

What ERC-8004 Provides#

• Agent Registry — on-chain map of agent IDs to metadata (name, version, capabilities)
• Reputation Scores — mutable scores (0–100) updated by authorized validators
• Validation Registry — check if an agent is registered and trusted
• Attestations — signed claims about agent behavior and purpose

Prerequisites#

• cast — Foundry tool for on-chain calls
• Wallet — EOA or smart wallet with gas for writes
• RPC URL — from Infura, Alchemy, or a public RPC
• ERC-8004 registry contract address — deployed on your target chain

Configuration#

bash

export AGENT_REGISTRY_ADDRESS="0x..."      # ERC-8004 registry address
export WEB3_RPC_URL="https://eth-mainnet.alchemy.io/..."  # or ETH_RPC_URL
export AGENT_WALLET_PRIVATE_KEY="0x..."    # for write transactions

Core Operations#

Register an Agent#

bash

cast send $AGENT_REGISTRY_ADDRESS \
  "register((string,string,bytes32,uint256))" \
  '("MyAgent","v1.0",0x...,1710000000)' \
  --rpc-url $WEB3_RPC_URL \
  --private-key $AGENT_WALLET_PRIVATE_KEY

Query Registration#

bash

# Check if agent is registered
cast call $AGENT_REGISTRY_ADDRESS \
  "isRegistered(address)" $AGENT_ADDRESS \
  --rpc-url $WEB3_RPC_URL

# Get agent metadata
cast call $AGENT_REGISTRY_ADDRESS \
  "getAgent(address)" $AGENT_ADDRESS \
  --rpc-url $WEB3_RPC_URL

Update Reputation (Validator Only)#

bash

# Validator updates reputation score (0-100)
cast send $AGENT_REGISTRY_ADDRESS \
  "updateReputation(address,uint256)" \
  $AGENT_ADDRESS 85 \
  --rpc-url $WEB3_RPC_URL \
  --private-key $VALIDATOR_PRIVATE_KEY

Query Reputation#

bash

cast call $AGENT_REGISTRY_ADDRESS \
  "getReputation(address)" $AGENT_ADDRESS \
  --rpc-url $WEB3_RPC_URL

Add Attestation#

bash

# Submit signed attestation
cast send $AGENT_REGISTRY_ADDRESS \
  "addAttestation(address,bytes)" \
  $AGENT_ADDRESS $SIGNATURE \
  --rpc-url $WEB3_RPC_URL \
  --private-key $ATTESTER_PRIVATE_KEY

Use Cases#

Trust Gate for DeFi Protocol#

Before executing a high-value tx, check the agent's reputation:

bash

REPUTATION=$(cast call $AGENT_REGISTRY_ADDRESS "getReputation(address)" $AGENT_ID --rpc-url $WEB3_RPC_URL)
[ "$REPUTATION" -lt 70 ] && echo "Low reputation — flag for human review"

Cross-Agent Trust#

When two agents need to cooperate:

bash

IS_REGISTERED=$(cast call $AGENT_REGISTRY_ADDRESS "isRegistered(address)" $PARTNER_AGENT --rpc-url $WEB3_RPC_URL)

Governance Participation#

Agents voting in a DAO can prove identity:

bash

cast call $AGENT_REGISTRY_ADDRESS "getAgent(address)" $PROPOSER_AGENT --rpc-url $WEB3_RPC_URL

Notes#

• ERC-8004 is an emerging standard — verify contract interface matches the deployed version
• Reputation is subjective — always check validator source and credibility
• Gas costs apply for all write operations (registration, reputation update, attestation)
• Test on testnet (Sepolia, Holesky) before mainnet deployment
• Common chains: Ethereum mainnet, Arbitrum, Optimism, Base

References#

• ERC-8004 Draft
• Ethereum Magicians Forum
• Foundry Book