ToolVet
76trust / 100

Ability Check

by AgentUtility.ai in Other

x402 APIPassing, checked 2 h ago

Resolves a d20 ability check, skill check, attack roll, or saving throw for tabletop RPGs. Rolls a d20 with an optional modifier and advantage/disadvantage, compares to a DC, and reports total, success/failure, and natural-20 / natural-1. Seedable. Use it as a d20 check resolver API for any RPG.

POST
https://x402.agentutility.ai/ability-check
Price
$0.005
per call in USDC
Uptime
83.3%
last 30 days
Response time
177 ms
4.1 s slowest 5%
Last check
Passed
2 h ago, next any minute now

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed

How to call it

POST https://x402.agentutility.ai/ability-check

Each call costs $0.005 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://x402.agentutility.ai/ability-check
content-type: application/json

{
  "advantage": true,
  "dc": 15,
  "modifier": 5,
  "seed": 2
}

Parameters

ParameterTypeRequiredDescription
advantagebooleanNoRoll twice, take the higher.
dcnumberNoDifficulty class to beat. Omit to just get the roll.
disadvantagebooleanNoRoll twice, take the lower.
modifiernumberNoTotal bonus/penalty added to the d20 (-20..40). Default 0.
seednumberNoOptional integer seed for a reproducible roll.

Example response

The provider's example. We can't check it without paying.

{
  "critical_failure": false,
  "critical_success": false,
  "d20_rolls": [
    15,
    7
  ],
  "dc": 15,
  "mode": "advantage",
  "modifier": 5,
  "natural_roll": 15,
  "success": true,
  "total": 20
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.005.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://x402.agentutility.ai/ability-check' \
  -H 'content-type: application/json' \
  --data-raw '{"advantage":true,"dc":15,"modifier":5,"seed":2}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://x402.agentutility.ai/ability-check' \
  -H 'content-type: application/json' \
  --data-raw '{"advantage":true,"dc":15,"modifier":5,"seed":2}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.005 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.005" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.005 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fx402.agentutility.ai%2Fability-check&method=POST
const res = await pay("https://x402.agentutility.ai/ability-check", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "advantage": true,
    "dc": 15,
    "modifier": 5,
    "seed": 2
  }),
});
console.log(res.status, await res.text());
Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.005 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.005"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://x402.agentutility.ai/ability-check",
        json={
            "advantage": True,
            "dc": 15,
            "modifier": 5,
            "seed": 2,
        },
    )
    print(res.status_code, res.text)

Security scan

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Recent checks

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38 h agoTimed out---
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