Category: on-chain agent identity registry standard / agent reputation-validation infrastructure / discovery-and-trust control plane
Summary: ERC-8004 is best understood as registry infrastructure for discovering and partially trusting autonomous agents rather than as an agent wallet, payment rail, or chat protocol. Its core move is to turn agents into portable on-chain identities with structured registration files, then pair that identity layer with standardized reputation and validation registries. The important categorization clue is that ERC-8004 does not define how agents reason, message, or get paid; it standardizes where outside parties look to discover agents, attach trust signals, and request third-party validation.
What it does:
Defines an Identity Registry built on ERC-721 plus URI-based registration files so agents get portable on-chain identifiers that can point to A2A, MCP, OASF, ENS, DID, web, and other service endpoints
Defines a Reputation Registry where clients can post structured feedback signals with tags, fixed-point scores, optional endpoint metadata, and optional off-chain evidence hashes
Defines a Validation Registry where validator contracts can receive requests and post responses about agent work, creating a generic hook for re-execution, zkML, TEE, or other assurance layers
Reserves and verifies an agentWallet metadata field so an agent identity can prove the payment wallet or operating wallet it wants associated with the registration
Supports optional HTTPS domain verification so endpoint domains can prove they correspond to the registered on-chain agent
Keeps payments explicitly out of scope while allowing payment evidence such as x402-linked proof-of-payment metadata to enrich reputation data
Key claims:
The abstract says the protocol uses blockchains to discover, choose, and interact with agents across organizational boundaries without pre-existing trust, which is the clearest signal that ERC-8004 belongs in the corpus as discovery-and-trust infrastructure
The motivation section says MCP and A2A cover capability listing and agent-to-agent interaction but do not solve discovery and trust, positioning ERC-8004 as the missing registry layer above existing agent communication protocols
The spec centers on three lightweight registries — identity, reputation, and validation — which shows the standard is building a trust data plane rather than a monolithic agent platform
The Identity Registry uses ERC-721 ownership plus URI-resolved registration files, meaning agent identity is intentionally portable, transferable, and compatible with existing NFT tooling rather than locked to a single vendor directory
The registration schema explicitly allows multiple service endpoints and multiple registrations, which makes ERC-8004 a coordination format for agent discovery across ecosystems instead of a single-network naming scheme
The Reputation Registry stores tagged feedback and exposes summary/read functions while leaving more complex aggregation off-chain, which is a strong clue that ERC-8004 wants to standardize composable trust inputs without dictating one canonical scoring model
The Validation Registry is generic enough for stake-secured re-execution, zkML verifiers, TEE oracles, or trusted judges, which matters because it keeps verification markets open instead of blessing one proof system
The spec says payments are orthogonal and only referenced as optional signal enrichment, reinforcing that ERC-8004 should be categorized as agent trust infrastructure, not as a payments protocol
Whitepaper: No standalone ERC-8004 whitepaper or litepaper surfaced in this pass. The clearest current sources were the canonical ERC page and the raw ERC markdown; see ../../whitepapers/erc-8004-primary-sources-2026-05-07.md.