Coinbase CDP + Agent Safe: agent payments signed by a CDP Server Wallet

Let an agent pay for APIs over x402 from a Coinbase CDP Server Wallet v2 account, inside limits the owner sets. The key stays in CDP; every payment is checked against the owner's merchant list, price and budget before CDP is asked to sign, so a prompt-injected agent can't redirect a payment or spend past the budget.

Tested live on Base mainnet (2026-10-08): a CDP Server Wallet account paid CoinStats 0.001 USDC through the SDK with exactly one CDP signature (tx). The same real 402 checked against a different payee was refused with zero CDP signatures. The guide's code below was then run verbatim and paid again (tx).

1. Install

npm install @deepfirstsearch/agent-pay @deepfirstsearch/agent-pay-cdp @coinbase/cdp-sdk viem

2. Use your CDP account as the payer

Create a Secret API Key and a Wallet Secret in the CDP Portal and set CDP_API_KEY_ID, CDP_API_KEY_SECRET and CDP_WALLET_SECRET. Create the account once (await cdp.evm.getOrCreateAccount({ name: "my-agent" })), send it a little USDC on Base (no ETH needed: the facilitator pays gas), and set CDP_ACCOUNT_NAME if you named it something else. This pays a real x402 API (0.001 USDC):

import { CdpClient } from "@coinbase/cdp-sdk";
import { createAgentPay, MerchantRegistry } from "@deepfirstsearch/agent-pay";
import { cdpPayer } from "@deepfirstsearch/agent-pay-cdp";

const cdp = new CdpClient(); // reads CDP_API_KEY_ID, CDP_API_KEY_SECRET and CDP_WALLET_SECRET
const payer = await cdpPayer({ cdp, name: process.env.CDP_ACCOUNT_NAME ?? "my-agent" }); // holds a little USDC on Base

const pay = createAgentPay({
  registry: new MerchantRegistry([{
    origin: "https://x402.coinstats.app",
    payTo: "0xa2AD8183209E5d2F7f0d8F995f5601a0bb5100c7", // CoinStats' Base address, as in its 402
    network: "eip155:8453",
    maxPerTx: 2_000n, // never more than 0.002 USDC per call
    pricePin: 1_000n, // 0.001 USDC, the published price
  }]),
  policy: { allowedNetworks: ["eip155:8453"], periodBudget: { amount: 100_000n, periodMs: 86_400_000 } },
  payer: () => payer,
  session: { readsUntrustedInput: true, accessesSensitiveData: false, canPay: true },
});
const plan = pay.commitPlan([{ origin: "https://x402.coinstats.app", maxSpend: 10_000n }], 60 * 60_000);

const res = await pay.fetch("https://x402.coinstats.app/coins/bitcoin?currency=USD", {}, { plan });
console.log(res.status, res.payment?.settlement.transaction);

cdpPayer takes { cdp, name } or { cdp, address } and only looks the account up (cdp.evm.getAccount); it never creates one.

3. Lock it down in CDP

Agent Safe decides whether to pay; CDP can enforce what the key may sign. Attach an account policy that only allows signEvmTypedData with USDC on Base (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) as the verifying contract, and keep the API key and wallet secret in the payment service, never in the model's process.

A note on EIP-712

x402 uses EIP-3009 authorizations (EIP-712 typed data). cdpPayer wraps the CDP account's own signTypedData with viem's toAccount, and we checked that its signatures recover to the account address. signTransaction and signMessage are disabled on purpose and there is no raw-hash sign: an x402 payer never needs them.

Source, issues and the full SDK: github.com/DeepFirstHQ/deepfirstsearch. Questions or a merchant you'd like covered: Discussions.

Agent Safe is an independent open-source project (MIT), live on Base mainnet as an unaudited beta. Not affiliated with Coinbase.