Example proposal — MainStreet reputation oracle integration for buyer agents

[philpof102-svg]

Context

MainStreet is a reputation oracle for AI agents on Base (ERC-8004 + x402, EIP-712 attestations). Deployed verifier: 0x7397adb9713934c36d22aa54b4dbbcd70263592b.

Browsing your typescript/examples/ folder, I noticed there's no example showing how a buyer agent vets a recipient before paying. Right now, examples like langchain-cdp-smart-wallet-chatbot show how to send onchain, not whether to trust the destination.

Proposal

Add typescript/examples/langchain-mainstreet-trust-gate/ showing a 10-line trust check before any x402 payment:

import { CdpAgentkit } from '@coinbase/cdp-agentkit-core';
import { recoverTypedDataAddress } from 'viem';

// Before paying any wallet via x402, fetch MainStreet attestation
async function safePay(agentkit, recipient, amountUSDC, minScore = 30) {
  const att = await fetch(`https://avisradar.app/api/agent/attestation/${recipient}`).then(r => r.json());
  if (!att.payload || att.payload.score < minScore) throw new Error(`MainStreet score ${att.payload?.score ?? 'unknown'} < ${minScore}`);
  return agentkit.run('transfer', { to: recipient, amount: amountUSDC });
}

Or onchain via the deployed verifier — see recipe.

Why this matters

833+ Base agents in x402 Bazaar. Some real, some throwaway. Today AgentKit users can pay any of them. A trust gate prevents users from paying low-rep wallets they wouldn't pay if they could see the score.

Happy to file a PR if this lands as priority. MIT-licensed, no MainStreet token, free score reads, $0.25 audit for deep due-diligence.

— @rakshasar on Farcaster · mainstreetxyz.base.eth · github.com/philpof102-svg/mainstreet

[evidai]

Adding a non-CDP reference point for the agent-payment thread.

We run LemonCake (https://lemoncake.xyz) as an x402 gateway without a Coinbase CDP dependency. Some notes that might be useful here:

Adapter pattern: getPaymentAdapter() reads LC_PAYMENT_ADAPTER. Today we ship two:

• StubAdapter (mock, for tests/onboarding)
• StripeOffSessionAdapter (production — Direct Charge + 3% application_fee, idempotent via charge_ref unique)
• USDC-on-Base path keeps the agent's own key as the transfer subject (no LemonCake-managed wallet — FSA-cleared design)

This means none of the CDP /verify quirks or setSettlementOverrides issues block us — the gateway does its own pre-flight (cap check + mandate-equivalent on the Buyer Key + idempotency check on charge_ref) and issues a Pay Token JWT only after the charge commits.

For embedded-wallet flows (Coinbase Onramp, Privy, etc.): they can fund a buyer-side wallet, and the agent's autonomous spending is still gated by our server-side caps. The two layers compose — the embedded wallet handles fiat-on-ramp, the gateway handles "did this agent exceed its budget?".

Production: $1 off-session card charge through the full loop verified 2026-06-02.
30-second demo (no signup): https://lemoncake.xyz/demo

(Disclosure: working on LemonCake. Sharing as an alternative implementation that doesn't rely on CDP, not pitching.)