---
title: Pay from coding tools
description: Add x402 payment handling to OpenCode and Claude Code.
image: https://developers.cloudflare.com/dev-products-preview.png
---

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# Pay from coding tools

The following examples show how to add x402 payment handling to AI coding tools. When the tool encounters a 402 response, it pays automatically and retries.

Both examples require:

* A wallet private key (set as `X402_PRIVATE_KEY` environment variable)
* The x402 packages: `@x402/fetch`, `@x402/evm`, and `viem`

## OpenCode plugin

OpenCode plugins expose tools to the agent. To create an `x402-fetch` tool that handles 402 responses, create `.opencode/plugins/x402-payment.ts`:

TypeScript

```

// Use base-sepolia for testing. Get test USDC from https://faucet.circle.com/

import type { Plugin } from "@opencode-ai/plugin";

import { tool } from "@opencode-ai/plugin";

import { x402Client, wrapFetchWithPayment } from "@x402/fetch";

import { registerExactEvmScheme } from "@x402/evm/exact/client";

import { privateKeyToAccount } from "viem/accounts";


export const X402PaymentPlugin: Plugin = async () => ({

  tool: {

    "x402-fetch": tool({

      description:

        "Fetch a URL with x402 payment. Use when webfetch returns 402.",

      args: {

        url: tool.schema.string().describe("The URL to fetch"),

        timeout: tool.schema.number().optional().describe("Timeout in seconds"),

      },

      async execute(args) {

        const privateKey = process.env.X402_PRIVATE_KEY;

        if (!privateKey) {

          throw new Error("X402_PRIVATE_KEY environment variable is not set.");

        }


        // Your human-in-the-loop confirmation flow...

        // const approved = await confirmPayment(args.url, estimatedCost);

        // if (!approved) throw new Error("Payment declined by user");


        const account = privateKeyToAccount(privateKey as `0x${string}`);

        const client = new x402Client();

        registerExactEvmScheme(client, { signer: account });

        const paidFetch = wrapFetchWithPayment(fetch, client);


        const response = await paidFetch(args.url, {

          method: "GET",

          signal: args.timeout

            ? AbortSignal.timeout(args.timeout * 1000)

            : undefined,

        });


        if (!response.ok) {

          throw new Error(`${response.status} ${response.statusText}`);

        }


        return await response.text();

      },

    }),

  },

});


```

When the built-in `webfetch` returns a 402, the agent calls `x402-fetch` to retry with payment.

## Claude Code hook

Claude Code hooks intercept tool results. To handle 402s transparently, create a script at `.claude/scripts/handle-x402.mjs`:

JavaScript

```

// Use base-sepolia for testing. Get test USDC from https://faucet.circle.com/

import { x402Client, wrapFetchWithPayment } from "@x402/fetch";

import { registerExactEvmScheme } from "@x402/evm/exact/client";

import { privateKeyToAccount } from "viem/accounts";


const input = JSON.parse(await readStdin());


const haystack = JSON.stringify(input.tool_response ?? input.error ?? "");

if (!haystack.includes("402")) process.exit(0);


const url = input.tool_input?.url;

if (!url) process.exit(0);


const privateKey = process.env.X402_PRIVATE_KEY;

if (!privateKey) {

  console.error("X402_PRIVATE_KEY not set.");

  process.exit(2);

}


try {

  // Your human-in-the-loop confirmation flow...

  // const approved = await confirmPayment(url);

  // if (!approved) process.exit(0);


  const account = privateKeyToAccount(privateKey);

  const client = new x402Client();

  registerExactEvmScheme(client, { signer: account });

  const paidFetch = wrapFetchWithPayment(fetch, client);


  const res = await paidFetch(url, { method: "GET" });

  const text = await res.text();


  if (!res.ok) {

    console.error(`Paid fetch failed: ${res.status}`);

    process.exit(2);

  }


  console.log(

    JSON.stringify({

      hookSpecificOutput: {

        hookEventName: "PostToolUse",

        additionalContext: `Paid for "${url}" via x402:\n${text}`,

      },

    }),

  );

} catch (err) {

  console.error(`x402 payment failed: ${err.message}`);

  process.exit(2);

}


function readStdin() {

  return new Promise((resolve) => {

    let data = "";

    process.stdin.on("data", (chunk) => (data += chunk));

    process.stdin.on("end", () => resolve(data));

  });

}


```

Register the hook in `.claude/settings.json`:

```

{

  "hooks": {

    "PostToolUse": [

      {

        "matcher": "WebFetch",

        "hooks": [

          {

            "type": "command",

            "command": "node .claude/scripts/handle-x402.mjs",

            "timeout": 30

          }

        ]

      }

    ]

  }

}


```

## Related

* [Pay from Agents SDK](https://developers.cloudflare.com/agents/agentic-payments/x402/pay-from-agents-sdk/) — Use the Agents SDK for more control
* [Charge for HTTP content](https://developers.cloudflare.com/agents/agentic-payments/x402/charge-for-http-content/) — Build the server side
* [Human-in-the-loop guide](https://developers.cloudflare.com/agents/guides/human-in-the-loop/) — Implement approval workflows
* [x402.org ↗](https://x402.org) — Protocol specification

```json
{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/agents/","name":"Agents"}},{"@type":"ListItem","position":3,"item":{"@id":"/agents/agentic-payments/","name":"Agentic Payments"}},{"@type":"ListItem","position":4,"item":{"@id":"/agents/agentic-payments/x402/","name":"x402"}},{"@type":"ListItem","position":5,"item":{"@id":"/agents/agentic-payments/x402/pay-with-tool-plugins/","name":"Pay from coding tools"}}]}
```