Extract entities

Pull emails, URLs, IPv4s, @mentions, and #hashtags out of free text. Send POST /api/extract-entities with the required field text and pay $0.002 per call over x402 or MPP, or call it free by solving a proof-of-work challenge. It returns a JSON object with emails, urls, mentions and hashtags.

Returns deduped lists.

Category: Text processing · Tags: extract emails urls entities nlp

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/extract-entities \
  -H "Content-Type: application/json" \
  -d '{"text":"ping @ada at ada@x.com see https://x.com #news"}'

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

Example response

{
  "emails": [
    "ada@x.com"
  ],
  "urls": [
    "https://x.com"
  ],
  "mentions": [
    "@ada"
  ],
  "hashtags": [
    "#news"
  ]
}

From an MCP client

catalog.call {
  "slug": "extract-entities",
  "params": {
    "text": "ping @ada at ada@x.com see https://x.com #news"
  }
}

On the hosted connector at https://agent402.tools/mcp, catalog.call runs extract-entities free (rate-limited, no wallet). Local install: npx -y agent402-mcp.

Errors and behavior

• text 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.
• Free tier: no outbound network call leaves the server for this tool, so proof-of-work (16 leading zero bits of sha256) pays for it.
• A GET or HEAD to /api/extract-entities 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?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/extract-entities", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "text": "ping @ada at ada@x.com see https://x.com #news"
  }),
});

No wallet? Pay with compute

Fetch a challenge, solve the sha256 puzzle (16 leading zero bits, a fraction of a second of CPU), and resend with the X-Pow-Solution header:

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=extract-entities")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/extract-entities", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"text":"ping @ada at ada@x.com see https://x.com #news"}) });

Part of these workflows

Extract entities is one step in these 3 skill packs, each sold as a single call:

• 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.
• Link preview card - The 'turn a URL into a card-shaped preview' workflow. Pull OpenGraph/Twitter card metadata, fetch the article body as a description fallback, normalize the og:image into a standard 1200×630 social card variant and a 400×400 square thumbnail, and extract URL/mention entities from the body for related-link surfacing. Five tools, one structured card payload ready for chat embeds, social shares, or RSS-to-card pipelines.
• Text hygiene - Turn a wall of dirty text - chat logs, scraped pages, user-generated content, log dumps - into something safe to store, search, and pipe into the next step. Measure first, redact PII before anything else touches the data, then dedupe, sort, extract entities, surface keywords, and grade the readability of what's left.

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