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feat: use facilitator for real on-chain settlement in withX402 MCP middleware #16

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Merged
adacapo21 merged 1 commit into from
Apr 3, 2026
Merged

feat: use facilitator for real on-chain settlement in withX402 MCP middleware #16

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15 changes: 10 additions & 5 deletions src/middleware/mcp.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,8 @@

import { isEnabled } from '../config.js';
import { getToolPrice, buildPaymentRequirements } from '../pricing.js';
import { parsePaymentHeader, verifyPayment } from '../verify.js';
import { parsePaymentHeader } from '../verify.js';
import { processPayment, verifyWithFacilitator } from '../facilitator.js';

type ToolResult = { content: Array<{ type: string; text: string }> };
type ToolHandler<T = unknown> = (params: T) => Promise<ToolResult>;
Expand Down Expand Up @@ -85,12 +86,16 @@ export function withX402<T extends ParamsWithPayment>(
return paymentError(toolName, 'Invalid payment signature format');
}

const result = await verifyPayment(payment, pricing.price);
if (!result.valid) {
const result = await processPayment(payment, toolName, () => handler(params));
if (!result.success) {
return paymentError(toolName, result.error ?? 'Unknown error');
}

return handler(params);
if (result.txHash) {
process.stderr.write(`[x402] settled on-chain: ${result.txHash}\n`);
}

return result.result!;
};
}

Expand Down Expand Up @@ -121,7 +126,7 @@ export async function checkPayment(
return paymentError(toolName, 'Invalid payment signature format');
}

const result = await verifyPayment(payment, pricing.price);
const result = await verifyWithFacilitator(payment, toolName);
if (!result.valid) {
return paymentError(toolName, result.error ?? 'Unknown error');
}
Expand Down