71trust / 100

Calc Rfm

by magent in Other

x402 APIPassing, checked 1 h ago

Relative fat mass (RFM) from height, waist, and sex (Woolcott 2018). Height and waist in meters in the paper; magent accepts height_cm or height_in and waist_cm. Deterministic published arithmetic with citation. Not a medical device, not a body-fat diagnosis, and not later obesity cutoffs. magent does not measure the patient.

POST
https://api.magentlab.com/api/calc/rfm
Price
$0.007
per call in USDC
Uptime
100%
last 30 days
Response time
163 ms
413 ms slowest 5%
Last check
Passed
1 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

POST https://api.magentlab.com/api/calc/rfm

Each call costs $0.007 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.magentlab.com/api/calc/rfm
content-type: application/json

{
  "items": [
    {
      "height_cm": 180,
      "height_in": 70,
      "sex": "male",
      "waist_cm": 90
    },
    {
      "height_cm": 180,
      "height_in": 70,
      "sex": "male",
      "waist_cm": 90
    }
  ]
}

Parameters

ParameterTypeRequiredDescription
itemsarray of objectYes

Example response

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

Example response, 40 lines
{
  "count": 2,
  "items": [
    {
      "citation": {
        "authors": "Woolcott OO, Bergman RN",
        "doi": "10.1038/s41598-018-29362-1",
        "id": "woolcott-2018",
        "pmid": "30030479",
        "source": "Sci Rep. 2018;8:10980",
        "title": "Relative fat mass (RFM) as a new estimator of whole-body fat percentage ─ A cross-sectional study in American adult individuals"
      },
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "formula": "rfm",
      "formula_expression": "RFM = 64 - (20 * (height_m / waist_m)) + (12 * sex); sex = 0 male, 1 female",
      "height_cm": 180,
      "rfm": 24,
      "sex": "male",
      "waist_cm": 90
    },
    {
      "citation": {
        "authors": "Woolcott OO, Bergman RN",
        "doi": "10.1038/s41598-018-29362-1",
        "id": "woolcott-2018",
        "pmid": "30030479",
        "source": "Sci Rep. 2018;8:10980",
        "title": "Relative fat mass (RFM) as a new estimator of whole-body fat percentage ─ A cross-sectional study in American adult individuals"
      },
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "formula": "rfm",
      "formula_expression": "RFM = 64 - (20 * (height_m / waist_m)) + (12 * sex); sex = 0 male, 1 female",
      "height_cm": 180,
      "rfm": 24,
      "sex": "male",
      "waist_cm": 90
    }
  ],
  "path": "/api/calc/rfm"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.007.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.magentlab.com/api/calc/rfm' \
  -H 'content-type: application/json' \
  --data-raw '{"items":[{"height_cm":180,"height_in":70,"sex":"male","waist_cm":90},{"height_cm":180,"height_in":70,"sex":"male","waist_cm":90}]}'

# 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.magentlab.com/api/calc/rfm' \
  -H 'content-type: application/json' \
  --data-raw '{"items":[{"height_cm":180,"height_in":70,"sex":"male","waist_cm":90},{"height_cm":180,"height_in":70,"sex":"male","waist_cm":90}]}' \
  | 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 $0.007 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.007" });
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 $0.007 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.magentlab.com%2Fapi%2Fcalc%2Frfm&method=POST
const res = await pay("https://api.magentlab.com/api/calc/rfm", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "items": [
      {
        "height_cm": 180,
        "height_in": 70,
        "sex": "male",
        "waist_cm": 90
      },
      {
        "height_cm": 180,
        "height_in": 70,
        "sex": "male",
        "waist_cm": 90
      }
    ]
  }),
});
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 $0.007 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.007"})
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.magentlab.com/api/calc/rfm",
        json={
            "items": [
                {
                    "height_cm": 180,
                    "height_in": 70,
                    "sex": "male",
                    "waist_cm": 90,
                },
                {
                    "height_cm": 180,
                    "height_in": 70,
                    "sex": "male",
                    "waist_cm": 90,
                },
            ],
        },
    )
    print(res.status_code, res.text)

Security scan

1 finding

  • Charges more than its listed price in payment
    Listed at $0.005, charges $0.007

Recent checks

WhenResultHTTPTimePrice
1 h agoPassed402180 ms$0.007
6 h agoPassed402145 ms$0.007
11 h agoPassed402230 ms$0.007
15 h agoPassed402240 ms$0.007
20 h agoPassed402217 ms$0.007
Show 10 older checks
24 h agoPassed402134 ms$0.007
28 h agoPassed402315 ms$0.007
32 h agoPassed402201 ms$0.007
36 h agoPassed402275 ms$0.007
41 h agoPassed402291 ms$0.007
45 h agoPassed402131 ms$0.007
2 days agoPassed402250 ms$0.007
2 days agoPassed402137 ms$0.007
2 days agoPassed402140 ms$0.007
3 days agoPassed402142 ms$0.007

History

11 Oct 2026Price changed from $0.005 to $0.007