Feature request: calling x402-paywalled tools from an agent

[genesiscode2026]

Feature request

Support for calling paywalled tools (specifically x402-protected HTTP endpoints) from an Agents SDK agent.

Problem

Tools are increasingly exposed as pay-per-call HTTP endpoints. There's no built-in way for an Agents SDK tool to receive a 402 Payment-Required challenge, sign the payment, and retry.

Proposed behavior

A helper (or tool wrapper) that:

1. Makes the tool request.
2. On HTTP 402, reads the Payment-Required header (x402 v2).
3. Signs the quoted Base USDC amount with a configured wallet.
4. Retries with a Payment-Signature header and returns the paid result.

Context

x402 is an open, HTTP-native payment standard (402 + Payment-Required/Payment-Signature headers) already used by several agent tools. A live example is POST https://genesis-agent-tools.genesisagenttools.workers.dev/api/flagships/release-guardian, which returns 402 on the first call and the paid verdict on a signed retry.

[jbeckwith-oai]

Thanks for taking the time to write this up and describe the x402 flow so clearly!

This overlaps with #2796, where we decided not to add built-in payment tooling to the SDK. The existing integration path is to wrap an application-configured x402 HTTP client in an async function tool. The client can handle the 402 challenge, payment signing, and retry, while your application owns wallet configuration and spending policy. The SDK's tool approval mechanism can gate the tool call, but approval of a quoted amount discovered in the HTTP response needs to be handled by the application or payment client.

We're closing this as a duplicate of #2796. If you run into a specific Agents SDK limitation while using that composition, please share a minimal example—we'd be happy to take a look. Thanks again for the suggestion!

[alfendysoon-hub]

VYTREL is a live external fixture for the exact helper proposed here: POST https://vytrel-control.vercel.app/api/verify-domain/batch, x402 v2/exact, 0.015 USDC on Base eip155:8453, no API key. Test sequence: make the JSON POST → read Payment-Required from the 402 → enforce the caller's spend cap → sign once → retry the identical 10-domain payload with Payment-Signature → return DNS A/MX evidence. Because it is POST+JSON, it validates request-body preservation as well as payment.