Agent Intel Hallucination Claim Checker
by SiteCheck Agent Intel & Dev in Other
Checks the named entities in an AI answer (up to 5 capitalised names) against Wikidata: each name is marked found or not found, with its Wikidata ID and description, and sentences containing a year are listed for review. It checks that entities exist, not that claims about them are true, so a found entity can still have a wrong fact.
https://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker- Price
- $0.003
- per call in USDC
- Uptime
- 0.0%
- last 30 days
- Response time
- -
- no timed checks yet
- Last check
- Failed
- 8 h ago, next any minute now
Reliability
Latest check failed 8 h ago: Amount "0.003" is not in atomic token units
Status and outage history · Atom feed · Watch with other listings
How to call it
POST https://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker
Each call costs $0.003 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://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker
content-type: application/json
{
"text": "Marie Curie won the Nobel Prize in 1903. She later moved to Mars in 1921."
}Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
text | string | Yes | The model answer to check, 10 to 5000 characters |
Example response
The provider's example. We can't check it without paying.
{
"checkedAt": "2026-10-23T09:35:21.542Z",
"entities": [
{
"description": "Polish-born French physicist and chemist (1867–1934)",
"name": "Marie Curie",
"status": "found",
"wikidataId": "Q7186"
},
{
"description": "set of annual international awards, primarily 5 established in 1895 by Alfred Nobel",
"name": "Nobel Prize",
"status": "found",
"wikidataId": "Q7191"
}
],
"notFoundCount": 0,
"note": "Existence check only: a found entity can still carry a wrong date or fact. Review the sentences with years yourself.",
"sentencesWithYears": [
"Marie Curie won the Nobel Prize in 1903.",
"She later moved to Mars in 1921."
],
"source": "https://www.wikidata.org/w/api.php"
}Call it from code
The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.003.
curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker' \
-H 'content-type: application/json' \
--data-raw '{"text":"Marie Curie won the Nobel Prize in 1903. She later moved to Mars in 1921."}'
# 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://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker' \
-H 'content-type: application/json' \
--data-raw '{"text":"Marie Curie won the Nobel Prize in 1903. She later moved to Mars in 1921."}' \
| grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decodeJavaScript: 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 $0.003 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.003" });
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 $0.003 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.fadeandco.workers.dev%2Fapi%2Fagent-intel%2Fhallucination-claim-checker&method=POST
const res = await pay("https://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker", {
method: "POST",
headers: { "content-type": "application/json" },
body: JSON.stringify({
"text": "Marie Curie won the Nobel Prize in 1903. She later moved to Mars in 1921."
}),
});
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 $0.003 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.003"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))
with x402_requests(client) as session:
res = session.post(
"https://api.fadeandco.workers.dev/api/agent-intel/hallucination-claim-checker",
json={
"text": "Marie Curie won the Nobel Prize in 1903. She later moved to Mars in 1921.",
},
)
print(res.status_code, res.text)Security scan
No findings
We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.
Recent checks
| When | Result | HTTP | Time | Price |
|---|---|---|---|---|
| 8 h ago | Amount "0.003" is not in atomic token units | 402 | 742 ms | $0.003 |
| 16 h ago | Amount "0.003" is not in atomic token units | 402 | 915 ms | $0.003 |
| 24 h ago | Amount "0.003" is not in atomic token units | 402 | 740 ms | $0.003 |
| 33 h ago | Amount "0.003" is not in atomic token units | 402 | 36 ms | $0.003 |
| 41 h ago | Amount "0.003" is not in atomic token units | 402 | 1.1 s | $0.003 |
Show 10 older checks
| 2 days ago | Amount "0.003" is not in atomic token units | 402 | 29 ms | $0.003 |
| 2 days ago | Amount "0.003" is not in atomic token units | 402 | 46 ms | $0.003 |
| 3 days ago | Amount "0.003" is not in atomic token units | 402 | 940 ms | $0.003 |
| 3 days ago | Amount "0.003" is not in atomic token units | 402 | 808 ms | $0.003 |
| 3 days ago | Amount "0.003" is not in atomic token units | 402 | 49 ms | $0.003 |
| 4 days ago | Amount "0.003" is not in atomic token units | 402 | 1.2 s | $0.003 |
| 4 days ago | Amount "0.003" is not in atomic token units | 402 | 45 ms | $0.003 |
| 4 days ago | Amount "0.003" is not in atomic token units | 402 | 43 ms | $0.003 |
| 4 days ago | Amount "0.003" is not in atomic token units | 402 | 45 ms | $0.003 |
| 5 days ago | Amount "0.003" is not in atomic token units | 402 | 70 ms | $0.003 |