Overview

Ethereum Attestation Service (EAS) is an open-source, permissionless protocol for making on-chain attestations — signed statements that one entity makes about another. Think of it as a programmable notarization layer for the blockchain. Anyone can define an attestation schema (what you’re attesting to), and anyone can issue attestations against that schema.

For prediction market agent builders, EAS solves a specific problem: how does an agent prove its track record, audit status, or marketplace verification in a way that anyone can independently verify? Moltbook handles social reputation and cross-service authentication; EAS handles cryptographic, on-chain proof.

The critical detail is that EAS is deployed on Base — the same Coinbase L2 that Agentic Wallets run on. This means an agent’s wallet address and its attestation history live on the same chain. A single Ethereum address becomes both the agent’s financial identity (holding USDC, executing trades) and its reputation anchor (accumulating verifiable attestations). No bridging, no cross-chain lookups, no separate identity systems.

EAS supports two modes. On-chain attestations are stored directly on Base, fully verifiable by any smart contract or off-chain reader. Off-chain attestations are signed but stored externally (IPFS, a database, or the attester’s own infrastructure), with only the attestation UID referenced on-chain. On-chain is best for high-stakes claims like audit results or marketplace verification. Off-chain works for lower-stakes signals like engagement metrics or preliminary reviews.

Key Features

Schema-based attestations — Schemas define the structure of what’s being attested. A marketplace operator might create a schema for “Verified Agent Listing” with fields for strategy type, historical return, audit date, and auditor address. A data provider might create a schema for “API Access Tier” with fields for rate limit and expiration. Schemas are registered on-chain and are reusable by anyone.

On-chain verifiability — Every on-chain attestation is stored in EAS’s contract on Base. Anyone can query the attestation by UID, verify who issued it, check when it was created, and confirm it hasn’t been revoked. No API calls to a third-party service, no trust assumptions beyond the chain itself.

Composability with Coinbase Agentic Wallets — Because both EAS and Agentic Wallets run on Base, an agent’s wallet address is also its attestation address. When a marketplace lists an agent, buyers can look up the agent’s wallet, see its attestation history, and verify claims — all from the same address used to hold funds and execute trades. This eliminates the identity fragmentation problem where reputation lives on one system and financial activity lives on another.

Revocable and timestamped — Attestations include a creation timestamp and can be marked as revocable at schema creation time. If an audit expires, a marketplace delists an agent, or a track record claim becomes outdated, the attester can revoke the attestation on-chain. Consumers can check revocation status alongside the original claim.

Multi-attester support — Any Ethereum address can issue attestations against any schema. This enables a trust web: a marketplace operator attests that an agent passed listing review, an independent auditor attests to its code quality, another agent attests to a successful collaboration, and a data provider attests to its API usage tier. Each attestation is independently verifiable and carries the attester’s address as its authority.

Referenced attestations — Attestations can reference other attestations, creating chains of evidence. An audit attestation can reference the specific agent listing attestation it reviewed. A track record attestation can reference individual trade settlement attestations. This builds a verifiable evidence graph rather than isolated claims.

Agent-Friendliness

AspectRating
SDK qualityGood — @ethereum-attestation-service/eas-sdk with ethers.js v6
DocumentationGood — docs.attest.org with schema registry explorer
Gas costs (Base)Excellent — ~$0.001 per on-chain attestation
Schema creationFree — only gas cost to register on-chain
GraphQL APIYes — query attestations by schema, attester, or recipient
Off-chain supportYes — signed attestations without gas costs
TypeScript supportFull — SDK is TypeScript-native

Pricing

Free protocol. The only costs are gas fees on Base, which are approximately $0.001 per on-chain attestation. Schema registration costs a one-time gas fee (similarly negligible on Base). Off-chain attestations incur zero gas costs but require external storage.

Best For

Building verifiable on-chain reputation for agent marketplace listings. If your agent needs to prove its track record, audit status, or verification tier in a way that buyers can independently check without trusting a centralized API, EAS on Base is the protocol to use. Especially powerful when combined with Coinbase Agentic Wallets, since wallet and reputation share the same address.