CryptoToolBox Server

An MCP server that lets AI agents read crypto wallets and prove on-chain payments across Ethereum and Solana.

It exists for one job: the x402 close-loop. Before an agent hands over work (an API response, a file, a result), it can verify the buyer's payment actually landed at the expected address — on-chain, with no backend and no API key.

Why this exists

Agents that sell things on-chain can't easily answer "did I get paid?" The primitives are not one-liners:

• Proving a transfer hit a specific recipient (native ETH/SOL or an ERC-20 like USDC)
• Reading an address's native + token balances
• Decoding what a transaction actually did
• Resolving ENS names so a payment request can arrive as vitalik.eth

crypto-payments-mcp wraps those reads behind clean MCP tools so any agent client can call them.

Install

npx -y crypto-payments-mcp

Or add it to your agent's MCP config:

{
  "mcpServers": {
    "crypto-payments-mcp": {
      "command": "npx",
      "args": ["-y", "crypto-payments-mcp"]
    }
  }
}

Works with Claude, Cursor, Hermes, ElizaOS, and any MCP client.

A hosted HTTP endpoint is also available for remote clients:

https://crypto-payments-mcp.irun2themoney.workers.dev/mcp

Tools

How it works

• No API key, no backend, no accounts. On-chain reads use free public RPCs (llamarpc for ETH, Solana mainnet for SOL).
• Stateless and safe-fail. If a chain can't be reached, the tool reports the error instead of guessing.
• Zero dependencies. Pure Node stdlib — drop it into any agent runtime.

Premium tool (x402)

Six tools are free to drive adoption. transaction_history is premium: an agent pays our address on-chain, then calls again with the payment tx hash; the server verifies the payment via verify_payment before returning data. No backend, no accounts — the payment is the access key.

• Price: 0.5 USDC (ERC-20), 0.001 ETH, or 0.01 SOL.
• Receive: ETH/USDC 0xc62b0aCba58E2Fc31cE2d27721Ee51154a808f52, SOL D19x8rMGo9dCv98UGaNuv6SM2Xov8Q5TxCkjrmfeynmn

License

MIT. Free to use, modify, and ship inside your own agent.