ToolVet
74trust / 100

Return Tail Stats

by heb-utils-x402.hebutils-api.workers.dev in Security & trust

x402 APIPassing, checked 2 h ago

Empirical lower-tail statistics of periodic returns you supply (decimals, 20-250 values): lower quantile and mean of observations at or below it. Numbers only, documented convention. Not advice, not a risk limit.

GET
https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats
Price
$0.05
per call in USDC
Uptime
97.1%
last 30 days
Response time
387 ms
716 ms 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 · Watch with other listings

How to call it

GET https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats

Each call costs $0.05 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.

GET https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats?confidence=0.95&returns=-0.012%2C0.004%2C0.009%2C-0.021%2C0.003%2C0.011%2C-0.007%2C0.002%2C-0.015%2C0.008%2C0.001%2C-0.004%2C0.006%2C-0.009%2C0.013%2C-0.002%2C0.005%2C-0.018%2C0.007%2C0.003

Parameters

ParameterTypeRequiredDescription
confidencestringNoup to 3 levels, 0.5-0.999
returnsstringYescomma-separated returns as decimals, 20-250 values

Example response

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

{
  "n": 20,
  "tails": [
    {
      "confidence": 0.95,
      "lower_quantile": -0.0187
    }
  ]
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.05.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats?confidence=0.95&returns=-0.012%2C0.004%2C0.009%2C-0.021%2C0.003%2C0.011%2C-0.007%2C0.002%2C-0.015%2C0.008%2C0.001%2C-0.004%2C0.006%2C-0.009%2C0.013%2C-0.002%2C0.005%2C-0.018%2C0.007%2C0.003'

# 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 - 'https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats?confidence=0.95&returns=-0.012%2C0.004%2C0.009%2C-0.021%2C0.003%2C0.011%2C-0.007%2C0.002%2C-0.015%2C0.008%2C0.001%2C-0.004%2C0.006%2C-0.009%2C0.013%2C-0.002%2C0.005%2C-0.018%2C0.007%2C0.003' \
  | 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 $0.05 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.05" });
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 $0.05 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fheb-utils-x402.hebutils-api.workers.dev%2Freturn-tail-stats
const res = await pay("https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats?confidence=0.95&returns=-0.012%2C0.004%2C0.009%2C-0.021%2C0.003%2C0.011%2C-0.007%2C0.002%2C-0.015%2C0.008%2C0.001%2C-0.004%2C0.006%2C-0.009%2C0.013%2C-0.002%2C0.005%2C-0.018%2C0.007%2C0.003");
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 $0.05 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.05"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://heb-utils-x402.hebutils-api.workers.dev/return-tail-stats?confidence=0.95&returns=-0.012%2C0.004%2C0.009%2C-0.021%2C0.003%2C0.011%2C-0.007%2C0.002%2C-0.015%2C0.008%2C0.001%2C-0.004%2C0.006%2C-0.009%2C0.013%2C-0.002%2C0.005%2C-0.018%2C0.007%2C0.003")
    print(res.status_code, res.text)

Security scan

No findings

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Recent checks

WhenResultHTTPTimePrice
2 h agoPassed402121 ms$0.05
7 h agoPassed402372 ms$0.05
12 h agoPassed402446 ms$0.05
16 h agoPassed402609 ms$0.05
21 h agoPassed40257 ms$0.05
Show 10 older checks
26 h agoPassed402716 ms$0.05
30 h agoPassed402413 ms$0.05
34 h agoPassed40293 ms$0.05
38 h agoPassed402782 ms$0.05
42 h agoPassed402643 ms$0.05
47 h agoPassed402181 ms$0.05
2 days agoPassed402543 ms$0.05
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3 days agoPassed402159 ms$0.05
3 days agoPassed402144 ms$0.05