Agent Payment Preflight Snippets

Copy these when adding payment-code preflight for AI agents.

Step 0

Before shipping agent payment code, run:

npx @monarch-shield/x402 doctor --ci --strict

x402 Client Preflight

import { checkBeforePayment } from '@monarch-shield/x402';



await checkBeforePayment({

  resourceUrl,

  payTo,

  amount: '0.01',

  asset: 'USDC',

  network: 'base',

  intent: 'agent buying paid API data through x402',

}, () => payX402(resourceUrl));

wallet.send Preflight

import { checkBeforePayment } from '@monarch-shield/x402';



await checkBeforePayment({

  resourceUrl: 'wallet://agent-send',

  payTo: tx.to,

  amount: tx.value,

  asset: 'USDC',

  network: 'base',

  intent: 'agent wallet transfer',

}, () => wallet.sendTransaction(tx));

Stripe PaymentIntent Preflight

import { checkBeforePayment } from '@monarch-shield/x402';



await checkBeforePayment({

  resourceUrl: 'stripe://payment-intents',

  payTo: stripeAccountId,

  amount: cartTotal,

  asset: currency,

  network: 'stripe',

  intent: 'agent-created checkout payment',

}, () => stripe.paymentIntents.create(paymentIntentParams));

Paid MCP Preflight

import { checkBeforePayment } from '@monarch-shield/x402';



await checkBeforePayment({

  resourceUrl: toolServerUrl,

  payTo: toolProvider,

  amount: quotedPrice,

  asset: 'USDC',

  network: 'x402',

  intent: `paid MCP tool call: ${toolName}`,

}, () => callPaidMcpTool(toolName, args));

GitHub Action

name: Monarch Payment Safety



on:

  pull_request:

  push:

    branches: [main]



jobs:

  monarch-doctor:

    runs-on: ubuntu-latest

    steps:

      - uses: actions/checkout@v4

      - name: Run Monarch Doctor

        run: npx @monarch-shield/x402 doctor --ci --strict

SARIF

npx @monarch-shield/x402 doctor --ci --strict --sarif-output monarch-doctor.sarif

Upload monarch-doctor.sarif to GitHub code scanning when you want unsafe

payment-code findings to show in pull requests.

Hosted Proof

MONARCH_PROJECT_TOKEN=... npx @monarch-shield/x402 doctor --ci --strict --report

Create a high-entropy MONARCH_PROJECT_TOKEN and store it as a secret. Monarch

hashes it locally before reporting. Hosted proof records aggregate reported

Doctor runs, not runtime enforcement or signed attestations.

Badge:

![Monarch Doctor](https://monarch-doctor-run.ghostmonarchalerts.workers.dev/projects/PROJECT_HASH/badge.svg)

User Notice

This project can move money. I’m adding Monarch Doctor as payment-code preflight for AI agents and running it before merge/go-live.