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ERC-8004 Trustless Agents: Identity, Reputation and Validation Registries

Guide · updated 2026-10-13 · Markdown variant

ERC-8004 Trustless Agents is a Draft Ethereum standard for discovering agents across organisations through three registries (identity, reputation, validation); what it specifies, what it cannot prove, and where it sits next to MCP, A2A and Web Bot Auth.

ERC-8004 Trustless Agents is an Ethereum standard proposal for discovering agents and establishing trust in them across organisational boundaries, using three on-chain registries. Decision rule: use it when you need a portable, cross-organisation agent identity and reputation record; it does not make an agent safe.

Key facts

• Status: Draft (Standards Track: ERC), per the EIP page on 2026-10-13. Drafts can change.
• Created 2025-08-13. Requires EIP-155, EIP-712, EIP-721 and EIP-1271.
• Three registries: identity, reputation, validation. The spec expects per-chain singleton deployments.
• Source: https://eips.ethereum.org/EIPS/eip-8004

What do the three registries do?

• Identity Registry: ERC-721 with the URIStorage extension. The token owner owns the agent. Key functions: register, setAgentURI (the URI resolves to a registration file listing endpoints such as MCP, A2A, ENS or DID), setMetadata, and setAgentWallet (requires an EIP-712 or ERC-1271 signature from the new wallet; the wallet is cleared on transfer).
• Reputation Registry: giveFeedback (signed fixed-point value plus optional tags), revokeFeedback, appendResponse (anyone may append), and getSummary. The agent owner cannot submit feedback for its own agent (nor can its approved operators).
• Validation Registry: validationRequest by the agent owner or operator and validationResponse by the named validator, with a response from 0 to 100 (0 failed, 100 passed, values between allowed). Validator incentives and slashing are outside the registry.

What are its limits?

• Sybil attacks: the spec says fake agents can inflate reputation. getSummary requires a non-empty list of client addresses, so you choose whose feedback to trust.
• Immutability: on-chain pointers and hashes cannot be deleted.
• The registry ties a registration file to an on-chain agent, but the spec states it cannot cryptographically show that advertised capabilities work or are non-malicious.
• The supportedTrust field is optional; if absent or empty, the registration is for discovery only, not trust.

How does it relate to MCP, A2A and Web Bot Auth?

By layer. MCP and A2A are communication protocols (see /resources/mcp-vs-a2a and /resources/a2a-protocol); the EIP motivates ERC-8004 by saying they do not inherently cover agent discovery and trust, and its registration file can point to an MCP or A2A endpoint. Web Bot Auth (/resources/web-bot-auth) is a different layer: HTTP Message Signatures that prove to an origin server who is making a request. The EIP treats payments as orthogonal and shows x402 as an optional proof-of-payment feedback field and a boolean x402Support flag in the registration file (see /resources/agent-wallets-x402).

See also: /resources/agent-identity-authentication, /resources/agent-wallets-x402, /resources/web-bot-auth

Sources

• ERC-8004: Trustless Agents (Draft), fetched 2026-10-13: https://eips.ethereum.org/EIPS/eip-8004

#erc-8004 #agent-identity #reputation #ethereum #x402 #agents #protocols

Category: Guide