Payments and x402

Payments and x402

Agent402's payments toolkit is non-custodial: it helps an agent move its own USDC with its own key. Agent402 never holds, receives, signs, or sends funds — it decodes quotes, reads public chain state, and builds the authorization you sign. All tools are keyless (public RPC) and work across Base, Polygon, Arbitrum, Optimism, and Ethereum (network param, default base).

Walkthrough with runnable examples: the x402 payments guide.

The tools

Tool	What it does
x402-quote	Probe any URL, decode its HTTP 402 payment terms (price, asset, network, pay-to)
ens-resolve	Resolve name.eth → Ethereum address (so a named recipient becomes payable)
usdc-balance	USDC balance of an address on any supported chain
gas-estimate	Current gas price (gwei + wei) for budgeting a transaction
transfer-authorization	Build the EIP-3009 transferWithAuthorization typed data to sign (gasless USDC)
tx-status	Confirmation status of a transaction (success / failed / pending / not found)
x402-verify	Confirm a USDC payment settled on-chain; optionally check recipient + min amount

The payment flow

1. x402-quote — what does this endpoint cost?
2. ens-resolve — turn a name.eth recipient into an address (if needed).
3. usdc-balance + gas-estimate — can the agent afford it?
4. transfer-authorization — build the EIP-712 object; the agent signs it with its own key (e.g. viem signTypedData).
5. x402-verify — confirm the settlement landed.

Why non-custodial

Custodial "pay for me" services must hold your funds — which means money transmission, KYC/AML, and trusting a middleman. These tools never touch your money: you keep your key, you sign, you send. That's the correct architecture for agent payments, and the reason this surface stays clean.

Notes

• Tools are wallet-only (paid per call in USDC via x402), so they are not exposed on the free hosted MCP connector — the payments surface is the paid HTTP / agent402-mcp path. See MCP Connector.
• USDC addresses are the native Circle deployments per chain; EIP-712 domain is USD Coin / version 2.
• Open source: src/tools/x402-kit.js.