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SeaOtter vs AgentStamp

Last reviewed: June 2026

AgentStamp is a trust layer for the agent economy: it gives every agent a cryptographic identity and a 0–100 reputation score so agents from different organizations can verify each other before they transact. SeaOtter is an acceptance layer for agent work: a hostile-by-default critic that grades what an agent actually produced against your written policy and gates it before it ships. The core difference: AgentStamp answers "can I trust this agent to deal with?", SeaOtter answers "is this specific output good enough to accept?"

At a glance

What AgentStamp is

AgentStamp certifies agent identity and reputation on-chain. It maintains a public registry of tens of thousands of ERC-8004 agents and issues a 0–100 trust score built from inputs like tier, endorsements, uptime, and momentum, returned as a W3C Verifiable Credential. It is standards-aligned (ERC-8004 reputation bridge, Ed25519-signed stamps, x402 micropayments, a hash-chained audit log) and trivially integrated — roughly one line of code — with webhook alerts on trust-score changes. It is a strong, well-designed choice for verifying the agents you transact with, especially external agents outside your own boundary.

What SeaOtter is

SeaOtter does not score who an agent is; it grades what an agent made. OtterScore is adversarially aligned to find reasons to block, and every grade is conditioned on the customer's own acceptance policy and rubric, so the same artifact can ship under one policy and block under another. It grades the trajectory as well as the final output, across code, text, documents, decks, spreadsheets, images, and video, and returns a four-band verdict (ship, route to fix, quarantine, block). Each verdict is signed (EIP-712), anchored on-chain on Base for tamper-evident proof, and the AgentOS control plane enforces the same gate across every model, framework, and cloud, on-prem or BYOC. The two are complementary: AgentStamp tells you which agent to engage; SeaOtter tells you whether that agent's work can ship.

When each one fits

Choose AgentStamp when: AgentStamp is the better fit when you need to verify the identity and standing of agents you transact with — especially third-party agents outside your boundary — using an interoperable, ERC-8004-aligned reputation score.

Choose SeaOtter when: SeaOtter is the better fit when you need to gate the actual work an agent produces — block or route output that fails your acceptance policy, multimodal, with signed audit evidence — rather than score the agent's standing.

Looking for a AgentStamp alternative?

If you are evaluating AgentStamp alternatives, the short answer: for gating enterprise agent work before production — a hostile, policy-conditioned critic that returns a ship / route-to-fix / quarantine / block verdict with signed audit evidence — SeaOtter is purpose-built. SeaOtter is the better fit when you need to gate the actual work an agent produces — block or route output that fails your acceptance policy, multimodal, with signed audit evidence — rather than score the agent's standing. If your need is closer to AgentStamp’s core job: AgentStamp is the better fit when you need to verify the identity and standing of agents you transact with — especially third-party agents outside your boundary — using an interoperable, ERC-8004-aligned reputation score. See the full ranked field in best AI agent evaluation tools.

Frequently asked questions

Try SeaOtter

SeaOtter is agent-native: grade your own work in one call, no human in the loop. Get a free key and run the loop from /llms.txt, or paste an artifact into the live demo to watch the critic push back.

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