29trust / 100

Tools Substitute

by Exercise Substitution Coach in Other

x402 APIFailing, checked 8 h ago

Exercise substitution for injuries, $0.02 USDC on Base: give a movement (e.g. barbell back squat) and an injury or limitation (e.g. knee pain, shoulder impingement) and get 3-5 safe alternative exercises with prescriptions, coaching cues and stop signs. Physio-informed, not medical advice. Gym, home gym, CrossFit, Hyrox.

POST
https://wod-api-production.up.railway.app/tools/substitute
Price
$0.02
per call in USDC
Uptime
28.8%
last 30 days
Response time
308 ms
396 ms slowest 5%
Last check
Failed
8 h ago, next any minute now

Run a free test callHow to call it

Reliability

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Latest check failed 8 h ago: Served content without asking for payment

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How to call it

POST https://wod-api-production.up.railway.app/tools/substitute

Each call costs $0.02 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://wod-api-production.up.railway.app/tools/substitute
content-type: application/json

{
  "equipment": [
    "dumbbells",
    "box",
    "bands"
  ],
  "limitation": "patellar tendinopathy, pain in deep knee flexion",
  "movement": "Barbell Back Squat"
}

Parameters

ParameterTypeRequiredDescription
equipmentarray of stringNoAvailable equipment; empty means "assume a full gym"
limitationstringYesInjury or limitation, e.g. "left shoulder impingement"
movementstringYese.g. "Barbell Overhead Press"

Example response

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

{
  "alternatives": [
    {
      "name": "Banded Spanish Squat Isometric",
      "prescription": "5 × 45 s @ RPE 6-7",
      "why": "Loads the tendon isometrically"
    },
    {
      "name": "DB Box Squat (high box)",
      "prescription": "4 × 8 @ RPE 7",
      "why": "Limits knee flexion depth"
    }
  ],
  "coaching_cues": [
    "Vertical shin",
    "Pain ≤ 3/10 during and after"
  ],
  "disclaimer": "Not medical advice.",
  "limitation": "patellar tendinopathy",
  "movement": "Barbell Back Squat",
  "stop_signs": [
    "Sharp pain below the kneecap"
  ],
  "why_avoid": "Deep knee flexion under axial load peaks patellar tendon stress."
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.02.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://wod-api-production.up.railway.app/tools/substitute' \
  -H 'content-type: application/json' \
  --data-raw '{"equipment":["dumbbells","box","bands"],"limitation":"patellar tendinopathy, pain in deep knee flexion","movement":"Barbell Back Squat"}'

# 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://wod-api-production.up.railway.app/tools/substitute' \
  -H 'content-type: application/json' \
  --data-raw '{"equipment":["dumbbells","box","bands"],"limitation":"patellar tendinopathy, pain in deep knee flexion","movement":"Barbell Back Squat"}' \
  | 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 $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
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 $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fwod-api-production.up.railway.app%2Ftools%2Fsubstitute&method=POST
const res = await pay("https://wod-api-production.up.railway.app/tools/substitute", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "equipment": [
      "dumbbells",
      "box",
      "bands"
    ],
    "limitation": "patellar tendinopathy, pain in deep knee flexion",
    "movement": "Barbell Back Squat"
  }),
});
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 $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://wod-api-production.up.railway.app/tools/substitute",
        json={
            "equipment": [
                "dumbbells",
                "box",
                "bands",
            ],
            "limitation": "patellar tendinopathy, pain in deep knee flexion",
            "movement": "Barbell Back Squat",
        },
    )
    print(res.status_code, res.text)

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