CryptoToolBox MCP Server

A free, zero-dependency Model Context Protocol (MCP) server for AI agents — the Web3 / crypto toolkit agents actually need, plus a set of free encoding/utility tools as a loss-leader. Built for agents that build payments, x402, and wallet features: the on-chain reads here are not one-liners, so the agent doesn't re-implement them.

All on-chain reads use free public RPCs (llamarpc for ETH, Solana mainnet for SOL) — no API key, no backend, no accounts. The premium tool is paid per-call and verified on-chain.

Quick start

npx -y @irun2themoney/crypto-toolbox-mcp

Or run the server file directly with Node 18+:

node server.cjs

Add to your agent's MCP config

{
  "mcpServers": {
    "crypto-toolbox": {
      "command": "node",
      "args": ["/absolute/path/to/server.cjs"]
    }
  }
}

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

Related MCP server: EVM MCP Server

Tools (34 total)

Web3 / crypto commerce (8) — the differentiators, built for agentic payments / x402:

Crypto validation (3): btc_address_validate, eth_address_validate, sol_address_validate

Encoding & hashing (8): base64, hex, url_encode, sha256, sha1, md5, json_format, json_minify, json_validate, json_diff (10 with diff)

Dates, strings, CSV/JSON, randomness (10+): epoch_to_date, date_to_epoch, case_convert, slugify, reverse, word_count, csv_to_json, json_to_csv, random_string, random_int, uuid

Premium (1): ai_text_analyze 🔒 — deep writing-quality analysis (Flesch reading ease, grade, passive voice, long-word ratio)

Premium tool (on-chain paywall)

ai_text_analyze costs 0.5 USDC (ERC-20), 0.001 ETH, or 0.01 SOL per call. Send the payment to the project wallet and pass the tx hash:

{
  "name": "ai_text_analyze",
  "arguments": { "text": "Your text here", "payment_chain": "USDC", "payment_txhash": "0x..." }
}

The server verifies the transaction on-chain (recipient + amount) via free public RPCs — no backend, no signup. Access is denied by default if the chain can't be reached (safe-fail).

Why a Web3 toolkit?

Encoding/json/hash tools are commodities (an agent already has them in stdlib). The Web3 reads — balances, token metadata, tx decoding, ENS — are exactly what agents building on-chain features must call and can't trivially do. That's the moat, and it aligns with where paid MCP usage actually lives (payments / x402 / web3).

Support

Tips (self-custody, no KYC):

• ETH / USDC: 0xc62b0aCba58E2Fc31cE2d27721Ee51154a808f52

• SOL: D19x8rMGo9dCv98UGaNuv6SM2Xov8Q5TxCkjrmfeynmn

• BTC: bc1qynsd9rv40d89fpudg242f73x2cjesam75gu43f

Live site + transparency: https://irun2themoney.github.io/freetoolbox/

MIT licensed.