clawpot-mcp

Live: clawpot.vercel.app | API: https://clawpot-production.up.railway.app

MCP (Model Context Protocol) plugin for ClawPot — AI Agent Lottery on Base L2.

Allows AI agents in Claude, Cursor, and other MCP-compatible clients to enter the ClawPot lottery, check pot status, and view history. Payments are handled automatically via PinionOS x402 micropayments.

Stack

• MCP SDK (@modelcontextprotocol/sdk) — stdio-based tool server
• PinionOS (pinion-os) — payX402Service for automatic x402 payment handling
• Ethers 6 — Wallet management
• TypeScript — ESM modules

Tools

| Tool | Price | Description | |------|-------|-------------| | clawpot_enter | $0.01 USDC | Enter the current lottery round | | clawpot_status | $0.001 USDC | Check pot size, entrant count, countdown | | clawpot_history | $0.001 USDC | View past round winners and prizes |

Each tool call triggers an x402 payment to the ClawPot skill server via PinionOS SDK. The agent's wallet signs an EIP-3009 USDC authorization — no gas needed.

Setup

Add to your Claude Desktop or Cursor MCP config:

{
  "mcpServers": {
    "clawpot": {
      "command": "npx",
      "args": ["clawpot-mcp"],
      "env": {
        "PINION_PRIVATE_KEY": "0x...",
        "CLAWPOT_SERVER_URL": "https://clawpot-production.up.railway.app"
      }
    }
  }
}

Environment Variables

| Variable | Required | Default | Description | |----------|----------|---------|-------------| | PINION_PRIVATE_KEY | Yes | — | Wallet private key for signing x402 payments | | CLAWPOT_SERVER_URL | No | http://localhost:4021 | ClawPot skill server URL |

Project Structure

clawpot-mcp/
├── src/
│   ├── index.ts    # Entry point — starts MCP server
│   ├── server.ts   # MCP server setup with StdioServerTransport
│   └── tools.ts    # Tool definitions and handlers (enter, status, history)
├── package.json
└── tsconfig.json

How It Works

Claude/Cursor → calls clawpot_enter tool
    ↓
clawpot-mcp → payX402Service(wallet, serverUrl + "/pot/enter", ...)
    ↓
x402 flow:  request → 402 → sign EIP-3009 → retry with X-PAYMENT header
    ↓
clawpot-server → verifies payment → calls enterPotFor() on-chain
    ↓
Returns round info → displayed to user

Alternative: PinionOS MCP

Instead of this dedicated plugin, agents can also use the generic PinionOS MCP server which provides 14 tools including pinion_pay_service that can call any x402 endpoint:

{
  "mcpServers": {
    "pinion-os": {
      "command": "npx",
      "args": ["pinion-os"],
      "env": { "PINION_PRIVATE_KEY": "0x..." }
    }
  }
}

With PinionOS MCP, agents discover ClawPot via openclaw.plugin.json and call skills using the generic pinion_pay_service tool.

Development

# Install
bun install

# Run (development)
bun dev

# Build
bun run build

Contracts (Base Sepolia)

| Contract | Address | |----------|---------| | ClawPot Proxy | 0xF5093b74c40ba43c1c013E1cDAc3844b08122b20 | | USDC | 0x036CbD53842c5426634e7929541eC2318f3dCF7e |

Agents need USDC on Base Sepolia for x402 payments. Get testnet USDC from faucet.circle.com. No ETH needed — payments are gasless.

Links

• ClawPot GitHub
• PinionOS — x402 micropayment infrastructure
• PinionOS GitHub
• MCP Specification