How much does Ethereum Selector Lookup cost?

$0.0050 per run. You only pay when you use it - no subscription, no monthly fee, no minimum spend.

Do I need an account to use Ethereum Selector Lookup?

No. Pay with USDC from your own wallet, or sign in and pay from your Balance. There is nothing to subscribe to and nothing to cancel.

Can I call Ethereum Selector Lookup from my own code?

Yes. POST to /api/agent/velvet_heron/ethereum-selector-lookup with an x402 payment header and the required inputs. The result comes back in the same HTTP response - no API key, no account.

Ethereum Selector Lookup

Name: Ethereum Selector Lookup
Brand: Amnt
Price: 0.0050 USD
Availability: InStock

by @velvet_heron

$0.0050/ runBase30 runs · 100% succeed · last 45 days ago

Call when you are decoding an Ethereum transaction and have only a 4-byte function selector. Send the selector like 0xa9059cbb. Returns every matching human-readable function signature from 4byte.directory, so the call can be named before it is simulated or signed.

A real run, free to read

0x70a08231

[
  {
    "id": 844293,
    "created_at": "2022-08-26T12:22:13.363345Z",
    "hex_signature": "0x70a08231",
    "text_signature": "watch_tg_invmru_119a5a98(address,uint256,uint256)",
    "bytes_signature": "p 1"
  },
  {
    "id": 166551,
    "created_at": "2019-09-24T11:36:57.296021Z",
    "hex_signature": "0x70a08231",
    "text_signature": "passphrase_calculate_transfer(uint64,address)",
    "bytes_signature": "p 1"
  },
  {
    "id": 166550,
    "created_at": "2019-09-24T11:36:37.525020Z",
    "hex_signature": "0x70a08231",
    "text_signature": "branch_passphrase_public(uint256,bytes8)",
    "bytes_signature": "p 1"
  },
  {
    "id": 143,
    "created_at":

Cut short here. Run it to get the whole answer.

The details

How Ethereum Selector Lookup is set up

Ways to use it

Run Ethereum Selector Lookup from anywhere

In your Discord server
Add the amnt bot to your server. Anyone types /run, picks Ethereum Selector Lookup from the list, and the answer appears in the channel for everyone to see. Each person links their amnt account once with /link so their own credits pay for their own runs.
```
/run agent: ethereum-selector-lookup prompt: what you want
```
Add the bot to Discord
Right here
Fill in the box above and the answer comes straight back. No account, no signup.
Open the run box

From your own code

One HTTP call with an API key. Credits are charged per run and the result comes back in the same response.

curl -X POST https://amnt.io/api/v1/run \
  -H "Authorization: Bearer amnt_sk_..." \
  -H "Content-Type: application/json" \
  -d '{"agent":"velvet_heron/ethereum-selector-lookup","input":{"prompt":"..."}}'

Developer docs

From Claude, Cursor, or any MCP client
Point your MCP client at amnt with an API key and Ethereum Selector Lookup shows up as a tool your assistant can call on its own.
```
https://amnt.io/api/mcp
```
How to connect

Price

What it costs

$0.0050per run

No subscription, no minimum. Pay from your Balance, or with USDC on Base, Solana or Hedera. The creator keeps 100% of every run.

FAQ

Questions

What does Ethereum Selector Lookup do?: Ethereum Selector Lookup is Call when you are decoding an Ethereum transaction and have only a 4-byte function selector. Send the selector like 0xa9059cbb. Returns every matching human-readable function signature from 4byte.directory, so the call can be named before it is simulated or signed., created by @velvet_heron. Describe what you want, pay once, and get the result in the same response.
How much does Ethereum Selector Lookup cost?: $0.0050 per run. You only pay when you use it - no subscription, no monthly fee, no minimum spend.
Do I need an account to use Ethereum Selector Lookup?: No. Pay with USDC from your own wallet, or sign in and pay from your Balance. There is nothing to subscribe to and nothing to cancel.
Can I call Ethereum Selector Lookup from my own code?: Yes. POST to /api/agent/velvet_heron/ethereum-selector-lookup with an x402 payment header and the required inputs. The result comes back in the same HTTP response - no API key, no account.

Details

How it works, proof it works, and how to call it from code

How it's performing

Runs

Successful

100%

Success rate

2026-09-06

Last run

Three steps

Tell it what you want
Fill in the box. No prompt-writing - the recipe is already built in.
Pay once, per run
$0.0050 a run. No subscription, no minimum, no account. You pay only when you press run.
Get the result in the same reply
Ethereum Selector Lookup returns your result immediately. Run it again with different inputs any time.

Use it from your own code

Ethereum Selector Lookup is a live HTTP endpoint. POST to it with an x402 payment header and the result comes back in the same response - no API key, no account.

curl -X POST https://amnt.io/api/agent/velvet_heron/ethereum-selector-lookup \
  -H "Content-Type: application/json" \
  -H "X-Payment: <x402-payment-header>" \
  -d '{ "prompt": "..." }'

Built by

More from @velvet_heron

See everything @velvet_heron has built →

Start your own agent from this one's setup - you fill in the rest.

Send a POST. You get a payment request (HTTP 402), pay it in USDC, and get the result in the same call. No key, no account.

POSThttps://amnt.io/api/agent/velvet_heron/ethereum-selector-lookup

Chain	Network id	Price	Pays
Base	eip155:8453	$0.0050 USDC	0xbe5a…04eb (creator)

Request body (JSON)

{
  "prompt": "react"
}

Response shape (JSON Schema)

{
  "type": "object",
  "properties": {
    "result": {
      "type": "string",
      "description": "The agent's response text"
    }
  }
}

Input schema (JSON Schema)

{
  "type": "object",
  "properties": {
    "prompt": {
      "type": "string",
      "description": "The instruction or prompt for the AI agent"
    }
  },
  "required": [
    "prompt"
  ]
}

curl (shows the 402 payment request)

curl -i -X POST https://amnt.io/api/agent/velvet_heron/ethereum-selector-lookup \
  -H "Content-Type: application/json" \
  -d '{"prompt":"react"}'

JavaScript (pays with x402)

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

// A wallet holding USDC on Base.
const signer = privateKeyToAccount(process.env.PRIVATE_KEY);
const pay = wrapFetchWithPayment(fetch, registerExactEvmScheme(new x402Client(), { signer }));

const res = await pay("https://amnt.io/api/agent/velvet_heron/ethereum-selector-lookup", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({"prompt":"react"}),
});
console.log(await res.json());

Price and details (GET)Tool manifest Skill for AI agents (skill.md)