按次付费 API 网关 MCP 服务器

x402engine-mcp 是一个面向 AI 代理的 MCP 服务器,用于通过 HTTP 402 发现和调用按次付费 API,并在 Base 或 Solana 上自动完成 USDC 支付,适用于大模型、图像/视频生成、搜索/抓取、代码执行、加密数据、旅行和 IPFS 等场景。

  • by agentc22
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在 GitHub 查看 agentc22/x402engine-mcp

使用说明

x402engine-mcp

Agent-friendly MCP server for x402engine. It lets agents discover and call pay-per-request APIs through HTTP 402, with automatic USDC payment on Base or Solana.

The live gateway covers LLMs, image and video generation, web search and scraping, code execution, crypto and wallet data, transaction simulation, audio, travel, and IPFS. This MCP exposes a curated tool set and live discovery for the full catalog.

Quick Start

Use a dedicated, low-balance payer wallet. The MCP signs x402 payments locally and never sends the private key to x402engine.

Base

{
  "mcpServers": {
    "x402engine": {
      "command": "npx",
      "args": ["-y", "x402engine-mcp@1.1.1"],
      "env": {
        "X402_EVM_PRIVATE_KEY": "0xYOUR_DEDICATED_PAYER_KEY",
        "X402_PAYMENT_NETWORK": "base",
        "X402_MAX_PAYMENT_USD": "1.00"
      }
    }
  }
}

Fund the wallet with USDC on Base. The x402 facilitator pays transaction gas; the wallet signs an EIP-3009 USDC authorization.

Solana

{
  "mcpServers": {
    "x402engine": {
      "command": "npx",
      "args": ["-y", "x402engine-mcp@1.1.1"],
      "env": {
        "X402_SOLANA_PRIVATE_KEY": "YOUR_BASE58_OR_JSON_PRIVATE_KEY",
        "X402_PAYMENT_NETWORK": "solana",
        "X402_MAX_PAYMENT_USD": "1.00"
      }
    }
  }
}

Fund the wallet with USDC on Solana and enough SOL for transaction fees.

Discovery Without a Wallet

The server starts without a wallet, and free tools such as discover_services and service_health still work. Paid tools return their x402 payment requirements until a wallet is configured.

claude mcp add x402engine -- npx -y x402engine-mcp@1.1.1

Hermes Agent

Install the x402engine skill and merge this server into the active Hermes profile's config.yaml:

mcp_servers:
  x402engine:
    command: npx
    args: ["-y", "x402engine-mcp@1.1.1"]
    env:
      X402_BASE_URL: "https://x402engine.app"
      X402_PAYMENT_NETWORK: "auto"
      X402_MAX_PAYMENT_USD: "0.10"

Start a new session and call discover_services or service_health; both are free. Keep the network on auto until a wallet is configured. For Base payments, store X402_EVM_PRIVATE_KEY in the profile's local .env, add X402_EVM_PRIVATE_KEY: "${X402_EVM_PRIVATE_KEY}" to the server's env, and change the network to base. Never put wallet keys in chat. The cap applies per request; authorize a separate total budget for each task.

Full Hermes setup guide · Installable skill

Payment Controls

Variable Default Description
X402_EVM_PRIVATE_KEY unset Dedicated payer key for Base USDC
X402_SOLANA_PRIVATE_KEY unset Base58 or JSON payer key for Solana USDC
X402_PAYMENT_NETWORK auto auto, base, or solana
X402_MAX_PAYMENT_USD 1.00 Hard per-request spending limit
X402_BASE_URL production gateway Override the gateway URL
X402_PAYMENT_HEADER unset Legacy pre-signed x402 header
X402_DEV_BYPASS unset Development bypass secret

In auto mode, Base is preferred when both keys are configured. Automatic payment only accepts the canonical USDC contracts on Base and Solana. It rejects unknown assets, unsupported networks, and amounts above the configured cap before signing.

MegaETH remains available to clients that supply their own compatible payment header.

MCP Tools

Category Tools
Discovery discover_services, service_health
Image and code generate_image, execute_code
Audio transcribe_audio
Crypto get_crypto_price, get_crypto_markets, get_crypto_history, get_trending_crypto, search_crypto, get_crypto_categories
Wallet and token get_wallet_balances, get_wallet_transactions, get_wallet_pnl, get_token_prices, get_token_metadata
IPFS pin_to_ipfs, get_from_ipfs
Travel search_flights, search_locations, search_hotels, search_cheapest_dates

Prices are included in each tool description and in live discovery. The gateway catalog can change independently of this package.

Discovery

Development

npm install
npm test
npm run build

Links