@deepfirstsearch/agent-pay-ai-sdk

@deepfirstsearch/agent-pay-ai-sdk

A Vercel AI SDK tool that lets a model fetch x402 APIs and pay them in USDC on Base, while an owner-signed, on-chain budget decides every payment. A prompt-injected model can ask for any URL; it can't pick the payee, the price or the limit.

Beta, unaudited. Use Base Sepolia or small amounts on Base mainnet.

npm install @deepfirstsearch/agent-pay-ai-sdk @deepfirstsearch/agent-pay ai zod

import { generateText, isStepCount } from "ai";
import { createAgentPay, MerchantRegistry, burnerPayers, vaultFunder } from "@deepfirstsearch/agent-pay";
import { paidFetchTool } from "@deepfirstsearch/agent-pay-ai-sdk";

const pay = createAgentPay({
  registry: new MerchantRegistry([
    { origin: "https://api.example.com", payTo: "0x…", network: "eip155:8453", maxPerTx: 50_000n, pricePin: 10_000n },
  ]),
  policy: { allowedNetworks: ["eip155:8453"], periodBudget: { amount: 1_000_000n, periodMs: 86_400_000 } },
  payer: burnerPayers(burnerSeed, vault),
  session: { readsUntrustedInput: true, accessesSensitiveData: false, canPay: true },
  ensureFunded: vaultFunder({ agent, publicClient, vault, usdc, intents: { "0x…": intentId }, tranche: 50_000n }),
});

// Seal the plan before the model reads anything untrusted.
const plan = pay.commitPlan([{ origin: "https://api.example.com", maxSpend: 200_000n }], 60 * 60_000);

const { text } = await generateText({
  model,
  tools: { paid_fetch: paidFetchTool({ pay, plan }) },
  prompt: "Get today's price index from api.example.com and summarize it.",
  stopWhen: isStepCount(5),
});

• The tool's input is only url, method, body and contentType. Merchants, price pins, caps and the plan live in pay and plan.

• A paid response comes back as { ok: true, status, paid: { amount, payTo, transaction }, body }, with the body fenced as untrusted data. A refusal comes back as { ok: false, refused: true, reason }, so the model can tell the user why. Since 0.3.0, with @deepfirstsearch/agent-pay >= 0.8.0, a policy refusal also carries code (stable, e.g. price_changed, payee_mismatch, plan_exhausted) and action (report, ask_owner, fix_config or retry_later); see "Refusal codes" in the SDK README. With older SDKs both are absent.

• Create the vault and the per-merchant budgets with the owner CLI.

• Try it offline first: use payer: () => privateKeyToAccount(generatePrivateKey()), drop ensureFunded, and point the registry at startMockServer from @deepfirstsearch/agent-pay/testing (see Test without a chain). For a model without an API key, MockLanguageModelV4 from ai/test.

Develop

npm ci && npm run typecheck && npm test   # includes a generateText run with a mock model against a mock x402 merchant