crypto-payments-mcp

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

Tool	What it does
verify_payment	Confirm a payment reached the expected recipient (native ETH/SOL or ERC-20). The x402 close-loop.
wallet_balance	Native + ERC-20 balance for any address.
token_info	ERC-20 metadata (symbol, name, decimals) from a contract.
decode_transaction	From/to/value + ERC-20 transfer for an Ethereum tx.
resolve_ens	ENS name → address, or address → primary ENS name.
chain_status	Latest block/slot — a quick chain-liveness check.
token_price	Spot USD price via a Chainlink feed (no API key).
transaction_history	PREMIUM — recent transactions for an address (indexer view free RPCs can't give). Gated by an on-chain payment.

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.