Xenarch — MCP Payment Server for AI Agents

MCP server that lets AI agents pay for x402-gated content and APIs with USDC micropayments on Base. No API keys. No signup. Non-custodial — Xenarch never holds funds. Auto-generates a wallet on first run.

How It Works

1. Discover    xenarch_check_gate("example.com")
               → { gated: true, price_usd: "0.003", protocol: "x402" }

2. Pay         xenarch_pay("example.com")
               → USDC sent on Base via splitter contract
               → { access_token: "eyJ...", expires_at: "..." }

3. Access      Re-request the URL with Authorization: Bearer <token>
               → Full content returned

No API keys. No signup. The agent pays directly on-chain — Xenarch never holds funds.

Agent MCP Server

Three tools for AI agents:

Tool	Description
xenarch_check_gate	Check if a URL/domain has a payment gate. Returns pricing and payment details.
xenarch_pay	Pay for gated content. Executes USDC payment on Base via the splitter contract.
xenarch_get_history	View past payments made by this wallet.

Example Responses

<details> <summary><code>xenarch_check_gate</code></summary>

{
  "gated": true,
  "gate_id": "7f3a1b2c-9d4e-4a8b-b6f1-2c3d4e5f6a7b",
  "price_usd": "0.003",
  "splitter": "0xC6D3a6B6fcCD6319432CDB72819cf317E88662ae",
  "collector": "0xabc123...publisher_wallet",
  "network": "base",
  "asset": "USDC",
  "protocol": "x402"
}

</details>

<details> <summary><code>xenarch_pay</code></summary>

{
  "success": true,
  "tx_hash": "0xdef456...abc789",
  "block_number": 28451023,
  "amount_usd": "0.003",
  "url": "example.com",
  "access_token": "eyJhbGciOiJIUzI1NiJ9...",
  "expires_at": "2026-04-10T15:05:00Z",
  "wallet": "0x123...your_wallet"
}

</details>

<details> <summary><code>xenarch_get_history</code></summary>

{
  "payments": [
    {
      "domain": "example.com",
      "amount_usd": "0.003",
      "tx_hash": "0xdef456...abc789",
      "paid_at": "2026-04-10T14:35:00Z"
    }
  ],
  "total_spent_usd": "0.003000",
  "count": 1,
  "wallet": "0x123...your_wallet"
}

</details>

Setup

1. Configure your wallet:

mkdir -p ~/.xenarch
cat > ~/.xenarch/wallet.json << 'EOF'
{
  "privateKey": "0xYOUR_PRIVATE_KEY"
}
EOF
chmod 600 ~/.xenarch/wallet.json

2. Add to Claude Code:

claude mcp add xenarch -- npx @xenarch/agent-mcp

Or add to Claude Desktop / any MCP client:

{
  "mcpServers": {
    "xenarch": {
      "command": "npx",
      "args": ["@xenarch/agent-mcp"],
      "env": {
        "XENARCH_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY"
      }
    }
  }
}

Environment Variables

Variable	Default	Description
XENARCH_PRIVATE_KEY	—	Wallet private key (overrides config file)
XENARCH_RPC_URL	https://mainnet.base.org	Base RPC endpoint
XENARCH_API_BASE	https://api.xenarch.dev	Xenarch platform API
XENARCH_NETWORK	base	Network (base or base-sepolia)
XENARCH_AUTO_APPROVE_MAX	—	Max USD to auto-approve without prompting

Examples

See xenarch-examples for working integration examples — Python agents, LangChain, CrewAI, Claude Desktop setup, and publisher middleware.

Development

npm install
npm run build

Structure

packages/
  shared/    — Payment logic, types, config (reused across servers)
  agent/     — MCP server for AI agents

License

MIT