qwed-ucp

Verification guards for Universal Commerce Protocol (UCP) - Catch AI math errors before payment.

When AI agents shop on behalf of users, they can make calculation errors. QWED-UCP catches these errors before payment is processed.

Installation

npm install qwed-ucp

Quick Start

const express = require('express');
const { createQWEDUCPMiddleware } = require('qwed-ucp');

const app = express();
app.use(express.json());

// Add QWED-UCP middleware
app.use(createQWEDUCPMiddleware());

app.post('/checkout-sessions', (req, res) => {
  // If we get here, checkout is verified!
  res.status(201).json({ status: 'created' });
});

app.listen(8182);

What It Verifies

| Guard | Verification | |-------|-------------| | Currency | Valid ISO 4217 codes (USD, EUR, JPY, etc.) | | Money | total = subtotal - discount + tax + shipping | | State | Valid checkout state transitions | | Line Items | price × quantity = line_total |

Configuration

app.use(createQWEDUCPMiddleware({
  verifyPaths: ['/checkout-sessions', '/checkout'],
  verifyMethods: ['POST', 'PUT', 'PATCH'],
  blockOnFailure: true,
  onVerified: (result, req) => {
    console.log('✅ Verified:', result.guardsPassed, 'guards passed');
  },
  onFailed: (result, req) => {
    console.log('❌ Failed:', result.error);
  }
}));

Response Headers

| Header | Description | |--------|-------------| | X-QWED-Verified | true or false | | X-QWED-Guards-Passed | Number of guards passed | | X-QWED-Error | Error message (on failure) |

Manual Verification

const { verifyCheckoutLocally } = require('qwed-ucp');

const result = verifyCheckoutLocally({
  currency: 'USD',
  totals: [
    { type: 'subtotal', amount: 100.00 },
    { type: 'tax', amount: 8.25 },
    { type: 'total', amount: 108.25 }
  ]
});

console.log(result.verified); // true

Links

• Documentation: docs.qwedai.com/docs/ucp/overview
• GitHub: QWED-AI/qwed-ucp
• Python Package: pip install qwed-ucp

License

Apache 2.0 - see LICENSE