cardzero-mcp

MCP Server for CardZero — AI Agent payment wallet on Base (USDC).

Gives your AI agent the ability to create wallets, check balances, send USDC payments, pay x402 paywalls, and view transaction history.

Prerequisites

You need a CardZero API Key and Wallet ID. Get them from the CardZero Dashboard after claiming a wallet.

Configuration

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "cardzero": {
      "command": "npx",
      "args": ["-y", "cardzero-mcp"],
      "env": {
        "CARDZERO_API_KEY": "czapi_...",
        "CARDZERO_WALLET_ID": "wallet_..."
      }
    }
  }
}

Claude Code

claude mcp add cardzero -- npx -y cardzero-mcp

Or add to .mcp.json in your project:

{
  "mcpServers": {
    "cardzero": {
      "command": "npx",
      "args": ["-y", "cardzero-mcp"],
      "env": {
        "CARDZERO_API_KEY": "czapi_...",
        "CARDZERO_WALLET_ID": "wallet_..."
      }
    }
  }
}

Cursor

Go to Settings > MCP Servers > Add new server:

• Name: cardzero
• Command: npx -y cardzero-mcp
• Environment variables: CARDZERO_API_KEY, CARDZERO_WALLET_ID

VS Code

Add to .vscode/settings.json:

{
  "mcp": {
    "servers": {
      "cardzero": {
        "command": "npx",
        "args": ["-y", "cardzero-mcp"],
        "env": {
          "CARDZERO_API_KEY": "czapi_...",
          "CARDZERO_WALLET_ID": "wallet_..."
        }
      }
    }
  }
}

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | CARDZERO_API_KEY | Yes | Agent API Key (czapi_...) from CardZero Dashboard | | CARDZERO_WALLET_ID | Yes | Wallet ID (wallet_...) from CardZero Dashboard | | CARDZERO_API_URL | No | API base URL (default: https://api.cardzero.ai/v1) |

Available Tools

| Tool | Description | |------|-------------| | create_wallet | Create a new wallet. Returns address and claim key for the owner. | | get_balance | Check current USDC balance. | | send_payment | Send USDC to any Ethereum address. 2% fee deducted automatically. | | list_payments | View recent payment history. | | pay_x402 | Pay for x402-protected HTTP resources (HTTP 402 paywall). | | get_payment | Check status of a specific payment by ID. |

How It Works

This MCP server is a thin client that calls the CardZero REST API. It runs locally on your machine and communicates with your AI assistant via stdio. No data is stored locally.

AI Assistant (Claude/Cursor/VS Code)
  <-> stdio (JSON-RPC)
cardzero-mcp (local process)
  <-> HTTPS
api.cardzero.ai

License

MIT