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AgentKit is a developer SDK from Tools for Humanity that lets AI agents cryptographically prove they’re operating on behalf of a verified human. It uses World ID — the largest human identity network — to link agent wallets to unique, Orb-verified humans on the World Chain. Browserbase integrates AgentKit to give human-verified agents access to Verified browsers — purpose-built Chromium recognized by bot protection partners — without requiring API keys, accounts, or KYC.
AgentKit verification is currently available through the x402 payment rail. Agents pay with USDC on Base and prove humanity with AgentKit to unlock premium features.

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Why it matters

Autonomous agents operating on the open web need a way to prove legitimacy. API keys prove account ownership. AgentKit proves something stronger: a real human is behind this agent. This matters for:
  • Permissionless access — agents can get premium browsers without signing up for an account
  • Abuse prevention — Verified browsers are reserved for human-backed agents
  • Privacy — agents prove humanity without revealing who the human is
  • Composability — the same wallet can pay for sessions (x402) and prove identity (AgentKit)

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How it works

1

Human verifies with World ID

The agent operator verifies their identity through World App using Orb verification — a one-time biometric check that confirms you’re a unique human.
2

Register wallet in AgentBook

The operator registers an EVM wallet address in the AgentBook smart contract on World Chain. This links the wallet to a verified human identity.
3

Agent signs proof headers

Before each browser session request, the agent signs an EIP-191 message proving it controls a registered wallet. The proof includes the target URL and a short TTL for replay protection.
4

Gateway verifies and upgrades

The Browserbase x402 gateway verifies the signature, checks AgentBook registration on World Chain, and upgrades the session to a Verified browser.

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What agents get

ScenarioBrowser
x402 payment onlyStandard
x402 + valid AgentKit proofVerified
The gateway never rejects a paid request over a missing or invalid proof — it silently falls back to a standard browser. Agents always get a working session.

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Getting started

Quickstart

Set up AgentKit verification and create your first human-verified browser session

x402 + AgentKit

Deep dive into the x402 payment flow with AgentKit premium unlock

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Further reading

AgentKit SDK

Official AgentKit documentation from Tools for Humanity

World Chain

The blockchain powering AgentBook identity verification

Agent Identity

How Browserbase handles agent authentication across all layers