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

```json
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```