Exa + Agent Safe: agents that pay for search inside a budget

Exa sells search and contents to agents over x402: no API key, pay per request in USDC on Base. Agent Safe makes that safe to leave unattended: the agent pays only Exa's address, only at Exa's price, only up to the budget you set, and a prompt-injected agent can't redirect or inflate a payment.

Tested live on Base mainnet (2026-10-07): an agent paid Exa 0.004 USDC for an instant search and got its results. Transaction.

1. Add Exa as a merchant

import { createAgentPay, MerchantRegistry } from "@deepfirstsearch/agent-pay";

const registry = new MerchantRegistry([{
  origin: "https://api.exa.ai",
  payTo: "0x6d6E695b09861467c7d462f5AAF31cF3540B9192", // Exa's Base address, as in its 402
  network: "eip155:8453",
  pricePin: 7_000n,  // 0.007 USDC (auto/fast search); instant is 0.004, deep 0.012
  maxPerTx: 12_000n, // hard cap per request
  label: "Exa search",
}]);

Exa's 402 also offers Solana and a batched gateway option; the SDK pays the standard Base USDC option and ignores the rest.

2. Pay per search

const pay = createAgentPay({
  registry,
  policy: { allowedNetworks: ["eip155:8453"], periodBudget: { amount: 1_000_000n, periodMs: 86_400_000 } },
  payer: () => yourWallet, // any viem account: local key, Turnkey, Privy, CDP…
  session: { readsUntrustedInput: true, accessesSensitiveData: false, canPay: true },
});
const plan = pay.commitPlan([{ origin: "https://api.exa.ai", maxSpend: 200_000n }], 60 * 60_000);

const res = await pay.fetch("https://api.exa.ai/search", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ query: "x402 spending limits", type: "auto", numResults: 5 }),
}, { plan });

3. Or give Claude/Cursor access through MCP

Add the merchant to the MCP server config and the agent can call paid_fetch on Exa without ever choosing the payee or the price:

{ "origin": "https://api.exa.ai", "label": "Exa search", "payTo": "0x6d6E695b09861467c7d462f5AAF31cF3540B9192",
  "price": "0.007", "tolerancePct": 0, "maxPerTx": "0.012", "maxSpend": "1.00" }

For on-chain budgets (caps enforced by a contract even if the agent's machine is compromised), see the owner CLI.

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

If Exa changes its price or address

The pins are deliberate. The 402 is written by the server, and a 402 that suddenly names another address or a higher price is exactly what a redirected or hijacked payment looks like. So when Exa reprices or rotates its wallet, Agent Safe refuses and nothing is signed:

a higher price gives price_changed (action ask_owner), or over_cap if it is also above your per-call cap;
a different address gives payee_mismatch (action report).

Confirm the change through Exa's own channels (its site, docs or announcement), then update pricePin or payTo in the registry, or price or payTo in the MCP config. To absorb small price changes without a prompt, allow a tolerance instead of removing the pin: toleranceBps in the registry (1000 = up to 10% over the pin) or tolerancePct in the MCP config.

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