Image dominant color

Extract the dominant colors of an image as a palette of hex values with pixel ratios. Send POST /api/image-dominant-color with no required fields (3 optional) and pay $0.003 per call over x402 or MPP (there is no free tier). It returns a JSON object with width, height, sampled and colors.

Send a public image URL or a base64 image, and optionally how many colors (1-10, default 5). Deterministic bucketed quantization; transparent pixels are ignored.

Category: Web & documents · Tags: image color palette dominant hex

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Parameters

Example request

curl -i -X POST https://agent402.tools/api/image-dominant-color \
  -H "Content-Type: application/json" \
  -d '{"url":"https://agent402.tools/fixtures/sample-photo.jpg","colors":3}'

Without payment this returns HTTP 402 Payment Required with the exact price for image-dominant-color; any x402 v2 or MPP client pays it and retries.

Example response

{
  "width": 120,
  "height": 80,
  "sampled": 6144,
  "colors": [
    {
      "hex": "#1f7a8b",
      "rgb": [
        31,
        122,
        139
      ],
      "ratio": 0.5938
    },
    {
      "hex": "#df7a1e",
      "rgb": [
        223,
        122,
        30
      ],
      "ratio": 0.2813
    },
    {
      "hex": "#22223a",
      "rgb": [
        34,
        34,
        58
      ],
      "ratio": 0.0938
    }
  ]
}

From an MCP client

catalog.call {
  "slug": "image-dominant-color",
  "params": {
    "url": "https://agent402.tools/fixtures/sample-photo.jpg",
    "colors": 3
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for image-dominant-color; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• Every field is optional. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• A GET or HEAD to /api/image-dominant-color returns the same 402 quote, so the price can be read without a body.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
client.setSpendControls?.(false); // keep your own spending ceiling in code
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/image-dominant-color", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "url": "https://agent402.tools/fixtures/sample-photo.jpg",
    "colors": 3
  }),
});

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