@asgcard/mcp-server

MCP Server for ASG Card — give AI agents autonomous virtual card management via x402 protocol on Stellar.

What is this?

This MCP server allows AI agents (Claude, Cursor, etc.) to create, fund, and manage virtual debit cards fully autonomously — no human-in-the-loop. Cards are paid with USDC on-chain via the x402 protocol.

Tools

| Tool | Description | |---|---| | create_card | Create a new virtual card (pays on-chain via x402) | | fund_card | Fund an existing card with more USDC | | list_cards | List all cards for your wallet | | get_card | Get card summary (balance, status) | | get_card_details | Get card number, CVV, expiry (sensitive) | | freeze_card | Temporarily freeze a card | | unfreeze_card | Re-enable a frozen card | | get_pricing | View available tier pricing |

Setup

Claude Code

claude mcp add asgcard -- node /path/to/mcp-server/dist/index.js \
  --env STELLAR_PRIVATE_KEY=S...

Claude Desktop / Cursor

Add to your MCP config file (~/.cursor/mcp.json or Claude Desktop settings):

{
  "mcpServers": {
    "asgcard": {
      "command": "npx",
      "args": ["-y", "@asgcard/mcp-server"],
      "env": {
        "STELLAR_PRIVATE_KEY": "YOUR_STELLAR_SECRET_KEY"
      }
    }
  }
}

Manual (from source)

cd mcp-server
npm install
npm run build

STELLAR_PRIVATE_KEY=S... node dist/index.js

Environment Variables

| Variable | Required | Default | Description | |---|---|---|---| | STELLAR_PRIVATE_KEY | ✅ | — | Stellar secret key (S...) for signing x402 payments and wallet auth | | ASGCARD_API_URL | ❌ | https://api.asgcard.dev | ASGCard API endpoint | | STELLAR_RPC_URL | ❌ | https://mainnet.sorobanrpc.com | Soroban RPC for transaction submission |

How it works

AI Agent (Claude / Cursor)
    ↕ stdio (MCP protocol)
@asgcard/mcp-server
    ↕ @asgcard/sdk (x402 create/fund)
    ↕ wallet-auth HTTP (list/get/freeze/unfreeze)
ASGCard API (api.asgcard.dev)
    ↕ x402 on Stellar (USDC)
4Payments → Visa/Mastercard Network

The server uses your Stellar private key to:

1. Sign x402 payments for card creation and funding (autonomous on-chain)
2. Sign wallet-auth requests for card management operations

Security

• Your private key never leaves the local process
• All x402 payments require on-chain USDC — no credit risk
• Wallet-auth uses ed25519 signatures with 5-min timestamp windows
• Card details are encrypted at rest on the server (AES-256)

License

MIT