Neural web search

Neural (embedding-based) web search over a curated web index, which finds pages by meaning rather than keyword overlap. Send POST /api/exa-search with the required field query and pay $0.012 per call over x402 or MPP (there is no free tier). It returns a JSON object with source, fetchedAt, query, searchType, count and 1 more.

Use it when a keyword engine returns the wrong thing: conceptual questions, 'pages like this one', or niche technical writing. Returns up to 10 results with title, URL, published date and author. Complements the keyword web search rather than replacing it.

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/exa-search \
  -H "Content-Type: application/json" \
  -d '{"query":"how agent-to-agent micropayment protocols settle onchain","numResults":5}'

Without payment this returns HTTP 402 Payment Required with the exact price for exa-search; any x402 v2 or MPP client pays it and retries.

Example response

{
  "source": "exa",
  "fetchedAt": "2026-09-13T20:00:00.000Z",
  "query": "how agent-to-agent micropayment protocols settle onchain",
  "searchType": "neural",
  "count": 1,
  "results": [
    {
      "title": "What is the x402 payment protocol?",
      "url": "https://example.com/x402-explained",
      "publishedDate": "2026-08-02T00:00:00.000Z",
      "author": null,
      "text": null
    }
  ]
}

From an MCP client

catalog.call {
  "slug": "exa-search",
  "params": {
    "query": "how agent-to-agent micropayment protocols settle onchain",
    "numResults": 5
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for exa-search; the stdio package pays it from a wallet or from an AGENT402_CREDITS_KEY issued earlier. Local install: npx -y agent402-mcp.

Errors and behavior

• query is required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/exa-search returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.({ maxAmountPerPayment: "$0.012" }); // refuse any quote above this tool's price
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/exa-search", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "query": "how agent-to-agent micropayment protocols settle onchain",
    "numResults": 5
  }),
});

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