Known-address label lookup

Label a known EVM address from a curated, committed dataset: major stablecoin + token contracts (USDC on every chain we settle on, USDT, DAI, WETH, WBTC), DEX routers (Uniswap, 1inch, 0x), canonical L1↔L2 bridges, large exchange hot/cold wallets, and burn/system addresses. Deterministic and offline — the provenance field states the dataset revision. Unknown addresses return {found:false}, not an error.

Input

Field	Type	Description
address *	string	0x-prefixed 40-char EVM address to label.

Example output

{
  "address": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
  "found": true,
  "labels": [
    {
      "label": "USDC",
      "category": "token",
      "network": "base",
      "note": "Circle USD Coin (native)"
    }
  ],
  "provenance": {
    "source": "curated in-repo dataset",
    "updated": "2026-07-13",
    "entries": 34
  }
}

Try it — see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/address-label \
  -H "Content-Type: application/json" \
  -d '{"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}'

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/address-label", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
  }),
});

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits — a fraction of a second of CPU, no money, no AI tokens), 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=address-label")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/address-label", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}) });

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.

• Contract audit — Triage a smart contract before an agent interacts with it: verified source, heuristic vulnerability scan, known-address check, function-selector resolution, and a read-only dry-run of the exact call you plan to make.
• Transaction forensics — Explain what an EVM transaction actually did: confirmation status, the raw transaction from the chain, decoded calldata with typed parameters, the resolved function signature, and labeled counterparties.

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