MCP server for sending physical mail with Solana cryptocurrency. Colosseum Agent Hackathon submission.
SaferSkills independently audited Solmail Mcp (Agent Skill) and scored it 100/100 (green). The audit ran 55 deterministic rules across Security, Supply Chain, Maintenance, Transparency, and Community; it found 0 high-severity and 0 lower-severity findings. The full rule-by-rule trace and per-finding evidence are below. Free, methodology-open.
Findings & checks · 0 flagged
Every scanned point with the score it earned and what moved between them.
First recorded scan — no prior version to compare against.
The primary manifest — the file an agent reads to learn what this artifact does.
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).
npx solmail-mcp@latestAdd to your MCP config:
{
"mcpServers": {
"solmail": {
"command": "npx",
"args": ["-y", "solmail-mcp"],
"env": {
"SOLANA_NETWORK": "devnet",
"SOLANA_PRIVATE_KEY": "your_base58_private_key"
}
}
}
}| 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 |
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 daysAgent composes letter --> MCP validates address --> Solana tx signed
--> Payment sent to merchant --> SolMail verifies on-chain
--> Lob.com prints letter --> USPS delivers --> Tracking returned| 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 |
| 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.
npm install && npm run build
npm run dev # Watch mode
npm start # Productiongit checkout -b feature/my-feature)MIT -- Purple Squirrel Media
~30 seconds. Free. No account. Every finding cites a rule and a line of evidence.