ToolVet
77trust / 100

Color Contrast

by Tanod utilpeek in Developer tools

x402 APIPassing, checked 3 h ago

Check WCAG color contrast: ratio and AA / AAA pass or fail for normal text, large text and UI components (utilpeek, Tanod). Use when an agent must check whether text and background colors meet WCAG AA or AAA contrast.

POST https://tanod.dev/v1/color/contrast

Last 30 days

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed

Uptime
100%
Response time
443 ms typical, 926 ms slowest 5%
Last check
3 h ago
Next check
any minute now

How to call it

POST https://tanod.dev/v1/color/contrast

Each call costs $0.001 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://tanod.dev/v1/color/contrast
content-type: application/json

{
  "background": "white",
  "foreground": "#777"
}

Parameters

ParameterTypeRequiredDescription
backgroundstringYesThe background color it sits on, in the same CSS color formats.
foregroundstringYesThe text or UI color, a CSS color: hex (#rgb, #rrggbb, #rrggbbaa), rgb() / rgba(), hsl() / hsla() or a CSS color name.

Example response

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

{
  "background": "#ffffffff",
  "composited": false,
  "foreground": "#777777ff",
  "large_text": {
    "aa": true,
    "aaa": false
  },
  "normal_text": {
    "aa": false,
    "aaa": false
  },
  "note": "WCAG 2.x contrast; pass/fail compares the unrounded ratio. Large text: at least 18 pt (24 px), or 14 pt (about 18.7 px) bold. Thresholds: AA 4.5 normal / 3 large, AAA 7 / 4.5, UI components and graphics 3 (SC 1.4.11).",
  "ratio": 4.48,
  "ratio_text": "4.48:1",
  "ratio_unrounded": 4.478089,
  "ui_components": {
    "aa": true
  }
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.001.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://tanod.dev/v1/color/contrast' \
  -H 'content-type: application/json' \
  --data-raw '{"background":"white","foreground":"#777"}'

# 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://tanod.dev/v1/color/contrast' \
  -H 'content-type: application/json' \
  --data-raw '{"background":"white","foreground":"#777"}' \
  | 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 $0.001 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.001" });
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 $0.001 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Ftanod.dev%2Fv1%2Fcolor%2Fcontrast&method=POST
const res = await pay("https://tanod.dev/v1/color/contrast", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "background": "white",
    "foreground": "#777"
  }),
});
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 $0.001 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.001"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://tanod.dev/v1/color/contrast",
        json={
            "background": "white",
            "foreground": "#777",
        },
    )
    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

WhenResultHTTPTimePrice
3 h agoPassed402926 ms$0.001
7 h agoPassed402912 ms$0.001
11 h agoPassed402946 ms$0.001
15 h agoPassed402443 ms$0.001
18 h agoPassed402843 ms$0.001
22 h agoPassed402459 ms$0.001
26 h agoPassed402806 ms$0.001
30 h agoPassed402360 ms$0.001
33 h agoPassed402383 ms$0.001
37 h agoPassed402259 ms$0.001
40 h agoPassed402826 ms$0.001
44 h agoPassed402347 ms$0.001
47 h agoPassed402274 ms$0.001
2 days agoPassed402383 ms$0.001
3 days agoPassed402258 ms$0.001