📬 solmail-mcp

Send real physical mail using Solana cryptocurrency from your AI agent. A Model Context Protocol server that enables Claude and other AI agents to send physical letters and postcards to real addresses worldwide, paid with SOL. Built for the Colosseum Agent Hackathon (#47).

Install

npx solmail-mcp@latest

Add to your MCP config:

{
  "mcpServers": {
    "solmail": {
      "command": "npx",
      "args": ["-y", "solmail-mcp"],
      "env": {
        "SOLANA_NETWORK": "devnet",
        "SOLANA_PRIVATE_KEY": "your_base58_private_key"
      }
    }
  }
}

Features

• Physical Mail -- Letters printed and mailed to 200+ countries via Lob.com
• Solana Payments -- Pay with SOL on devnet (testing) or mainnet (production)
• Non-Custodial -- Direct wallet control, no intermediaries
• AI-Native -- Built specifically for MCP agent integration
• Demo Mode -- Test with devnet SOL and Lob test API at zero cost

Tools (4)

Tool	Description
get_mail_quote	Get price quote for sending mail (country, color options)
send_mail	Send a physical letter with Solana payment
get_wallet_balance	Check agent wallet SOL balance
get_wallet_address	Get wallet address for funding

Usage Example

You: Send a thank you note to John Doe at 123 Main St, San Francisco, CA 94102

Claude: [calls get_mail_quote] Cost: $1.50 (~0.015 SOL) for domestic US mail
        [calls send_mail] Letter sent!
          Letter ID: ltr_abc123
          Tracking: 9400000000000000000000
          Payment: 0.015 SOL (tx: 5j7s...)
          Delivery: 3-5 business days

How It Works

Agent composes letter --> MCP validates address --> Solana tx signed
    --> Payment sent to merchant --> SolMail verifies on-chain
    --> Lob.com prints letter --> USPS delivers --> Tracking returned

Pricing

Type	Price	SOL (at $100/SOL)
US Domestic	$1.50	~0.015 SOL
International	$2.50	~0.025 SOL
Color printing	+$0.50	+0.005 SOL
Solana tx fee	~$0.00025	~0.0000025 SOL

Configuration

Variable	Required	Description
SOLANA_PRIVATE_KEY	Yes	Agent wallet private key (base58)
SOLANA_NETWORK	No	devnet (default) or mainnet-beta
SOLMAIL_API_URL	No	API endpoint (default: https://solmail.online/api)
MERCHANT_WALLET	No	Custom payment destination

Important: Create a dedicated wallet with limited funds for AI agents. Never use your primary wallet.

Development

npm install && npm run build
npm run dev    # Watch mode
npm start      # Production

Related Projects

• solana-mcp-server-app -- Solana wallet + DeFi MCP
• coldstar-colosseum -- Air-gapped Solana vault
• ordinals-mcp -- Bitcoin Ordinals MCP server
• cpanel-mcp -- cPanel hosting MCP server

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/my-feature)
3. Commit your changes
4. Open a Pull Request

Links

• Website | npm | MCP Docs

License

MIT -- Purple Squirrel Media