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What is EAS? Ethereum Attestation Service Explained for AI Agents

In the world of autonomous AI agents, trust isn't built on promises — it's built on verifiable data. The Ethereum Attestation Service (EAS) provides exactly that: a standard way to create, verify, and revoke on-chain attestations about anything.

For AI agents, EAS is becoming the backbone of reputation. Here's what you need to know.

What is EAS?

EAS is a protocol on Ethereum (and other EVM chains including Base) that allows any entity to make attestations — structured statements of fact — on-chain. An attestation can be about anything: "This wallet is controlled by a verified human," "This agent passed a security audit," or "This address completed 100 successful trades."

Key properties of EAS attestations:

• Verifiable — Anyone can verify the attestation on-chain
• Non-transferable — Attestations are tied to specific addresses
• Revocable — The issuer can revoke attestations if circumstances change
• Schema-based — Attestations follow defined schemas for interoperability
• Public — All attestations are visible on-chain by default

How AI Agents Use EAS

Autonomous agents can issue and consume attestations as part of their decision-making process:

Endorsements Between Agents

After a successful transaction, Agent A can issue an attestation endorsing Agent B. This attestation says, in effect, "Agent A confirms that Agent B was a reliable counterparty for this trade." Future counterparties can check this attestation when evaluating whether to interact with Agent B.

Identity Verification

An agent can carry attestations from trusted issuers proving its identity or credentials. For example, a KYC attestation from a verified issuer, or a "this agent passed our audit" attestation from a security firm.

Reputation Portability

Because EAS is cross-chain, an attestation issued on Ethereum mainnet can be read on Base, Arbitrum, Optimism, or Polygon. This means agents can carry reputation across chains — a key capability for multi-chain reputation scoring.

How AgentTrust Reads EAS Attestations

AgentTrust treats EAS attestations as a quantitative factor in its reputation scoring algorithm. When computing a wallet's trust score, AgentTrust:

• Queries the EAS indexer for attestations about the wallet (endorsements from others)
• Queries attestations by the wallet (how the agent endorses others — signals engagement)
• Weighs the reputation of the attestation issuers (an endorsement from an AAA-rated agent counts more)
• Considers attestation recency (recent endorsements have higher weight)

This creates a recursive trust graph: reputable agents endorsing other agents, which affects their scores, which determines the weight of future endorsements. It's a decentralized, autonomous reputation system.

Schemas and Interoperability

EAS uses schemas (encoded as UIDs) to define what data an attestation contains. Common schemas for AI agents include:

• Agent Endorsement — "Wallet A endorses Wallet B for [category]"
• Transaction Completion — "Transaction 0x... completed successfully between A and B"
• Score Snapshot — "AgentTrust score for address 0x... was 85 at block N"

The Future of EAS for Agents

As the agent economy grows, EAS will become the standard for identity and reputation. We expect to see:

• Attestation marketplaces where agents can purchase endorsements from reputable issuers
• Automated attestation issuance — agents that automatically endorse counterparties after successful interactions
• Cross-chain attestation relaying — carry reputation from any chain to any other chain

EAS turns reputation into infrastructure. Combined with AgentTrust's scoring algorithm and x402 payments, it gives autonomous agents everything they need to trust each other. Learn more about building trustworthy AI agents with on-chain reputation.