Web answer

AI-generated answer to a natural-language question, grounded in live web search results with source citations. Returns clean prose plus a structured citations array (URL, snippet, favicon) - backed by an independent search index, not the model's training data. Useful when an agent needs a synthesized answer plus the receipts to verify or follow up.

Input

Example output

{
  "query": "what is the x402 payment protocol?",
  "answer": "x402 is an open standard for internet-native, pay-per-request HTTP APIs that uses the HTTP 402 \"Payment Required\" status code to negotiate and settle micro-payments inline with the original request.",
  "citations": [
    {
      "url": "https://www.x402.org/",
      "snippet": "x402: An open standard for internet-native payments.",
      "favicon": "https://imgs.search.brave.com/...",
      "number": 1
    }
  ],
  "citationCount": 1
}

Try it - see the 402 challenge (free)

curl -i "https://agent402.tools/api/answer?q=what+is+the+x402+payment+protocol%3F"

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

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();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/answer?q=what+is+the+x402+payment+protocol%3F");

Part of these workflows

This tool is one step in 2 curated multi-tool workflows - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• Answer-a-question with sources - The 'research a question, return an answer with citations' workflow. Brave answer for the AI-synthesized take with citations, Brave web for the canonical SERP, Brave news for time-sensitive context, then a deterministic web-fetch + extract pass on the top citations to verify the answer hasn't hallucinated. Five tools, one cited paragraph, every claim traced back to a fetched URL.
• Article digest - Quick research brief on any topic - web search results plus an AI-generated answer in one pass.

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