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Pay For Service

Make a paid API request to an x402 endpoint with automatic USDC payment. Use when you or the user want to call a paid API, make an x402 request, use a paid service, or pay for an API call. Use after finding a service with search-for-service.

$ npx promptcreek add pay-for-service

Auto-detects your installed agents and installs the skill to each one.

What This Skill Does

This skill uses the npx awal@2.0.3 x402 pay command to call paid API endpoints with automatic USDC payment on Base. It provides options for specifying the HTTP method, request body, query parameters, and custom headers. This skill is useful for agents needing to interact with paid x402 services.

When to Use

  • Call paid API endpoints.
  • Make automatic USDC payments.
  • Specify HTTP method for the request.
  • Include request body as JSON.
  • Add query parameters to the URL.
  • Set custom HTTP headers.

Key Features

Uses the `npx awal@2.0.3 x402 pay` command.
Supports various HTTP methods and request options.
Provides input validation to prevent shell injection.
Requires authentication before making payments.
Offers options for setting max payment amount.
Uses USDC atomic units for payment.

Installation

Run in your project directory:
$ npx promptcreek add pay-for-service

Auto-detects your installed agents (Claude Code, Cursor, Codex, etc.) and installs the skill to each one.

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Making Paid x402 Requests

Use the npx awal@2.0.3 x402 pay command to call paid API endpoints with automatic USDC payment on Base.

Confirm wallet is initialized and authed

npx awal@2.0.3 status

If the wallet is not authenticated, refer to the authenticate-wallet skill.

Command Syntax

npx awal@2.0.3 x402 pay <url> [-X <method>] [-d <json>] [-q <params>] [-h <json>] [--max-amount <n>] [--json]

Options

| Option | Description |

| ----------------------- | -------------------------------------------------- |

| -X, --method | HTTP method (default: GET) |

| -d, --data | Request body as JSON string |

| -q, --query | Query parameters as JSON string |

| -h, --headers | Custom HTTP headers as JSON string |

| --max-amount | Max payment in USDC atomic units (1000000 = $1.00) |

| --correlation-id | Group related operations |

| --json | Output as JSON |

USDC Amounts

X402 uses USDC atomic units (6 decimals):

| Atomic Units | USD |

| ------------ | ----- |

| 1000000 | $1.00 |

| 100000 | $0.10 |

| 50000 | $0.05 |

| 10000 | $0.01 |

IMPORTANT: Always single-quote amounts that use $ to prevent bash variable expansion (e.g. '$1.00' not $1.00).

Input Validation

Before constructing the command, validate all user-provided values to prevent shell injection:

  • url: Must be a valid URL starting with https:// or http://. Reject if it contains spaces, semicolons, pipes, backticks, or shell metacharacters.
  • data (-d): Must be valid JSON. Always wrap in single quotes to prevent shell expansion.
  • max-amount: Must be a positive integer (^\d+$).

Do not pass unvalidated user input into the command.

Examples

# Make a GET request (auto-pays)

npx awal@2.0.3 x402 pay https://example.com/api/weather

Make a POST request with body

npx awal@2.0.3 x402 pay https://example.com/api/sentiment -X POST -d '{"text": "I love this product"}'

Limit max payment to $0.10

npx awal@2.0.3 x402 pay https://example.com/api/data --max-amount 100000

Prerequisites

  • Must be authenticated (npx awal@2.0.3 status to check, see authenticate-wallet skill)
  • Wallet must have sufficient USDC balance (npx awal@2.0.3 balance to check)
  • If you don't know the endpoint URL, use the search-for-service skill to find services first

Error Handling

  • "Not authenticated" - Run awal auth login first, or see authenticate-wallet skill
  • "No X402 payment requirements found" - URL may not be an x402 endpoint; use search-for-service to find valid endpoints
  • "Insufficient balance" - Fund wallet with USDC; see fund skill
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Supported Agents

Claude CodeCursorCodexGemini CLIAiderWindsurfOpenClaw

Details

License
MIT
Source
admin
Published
3/18/2026

Tags

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