MCP Blockchain Server

An MCP server that lets AI assistants read blockchain data and prepare transactions — while the user keeps full custody of their keys and signs every transaction in their own wallet.

It runs as a single, self-contained process. No database, no Redis, no API keys, no separate frontend to build. Point your MCP client at it and go.

┌──────────────┐   MCP (stdio)   ┌─────────────────────┐   RPC    ┌────────────┐
│ AI assistant │ ──────────────► │  mcp-blockchain     │ ───────► │ Blockchain │
│ (Claude …)   │ ◄────────────── │  server             │ ◄─────── │  (EVM)     │
└──────────────┘                 │   + signing web page │          └────────────┘
                                 └─────────┬───────────┘
                                           │ opens link, signs in wallet
                                           ▼
                                     ┌───────────┐
                                     │   User    │  (MetaMask / Rabby / …)
                                     └───────────┘

Why this design

The hard problem in AI + blockchain is letting an assistant act without ever touching private keys. This server solves it by splitting the work:

• Reads (balances, contract state) happen server-side and return directly to the assistant.
• Writes are only ever prepared server-side. The server hands back a URL; the user opens it, reviews the details, and signs in their own wallet. The wallet broadcasts the transaction. The server only ever learns the resulting transaction hash. Private keys never reach the server.

Quick start

Requirements: Node.js 18+. No clone, no build, no API keys.

Add the server to any MCP client that launches stdio servers. For Claude Desktop, open Settings → Developer → Edit Config and add:

{
  "mcpServers": {
    "blockchain": {
      "command": "npx",
      "args": ["-y", "mcp-blockchain-server"]
    }
  }
}

Restart the client. You can now ask things like "What's the ETH balance of vitalik.eth?" or "Send 0.01 test ETH to 0x… on Sepolia." For a send, the assistant returns a link — open it, review, and sign in your wallet.

No configuration is required: the server ships with free public RPC endpoints and defaults to the Sepolia testnet.

Use it in other clients

The same npx command works anywhere that runs an MCP stdio server — the config shape is identical across clients:

{ "command": "npx", "args": ["-y", "mcp-blockchain-server"] }

This is the block to drop into Cursor (.cursor/mcp.json), Cline, Windsurf, VS Code (.vscode/mcp.json), and others. To pass options, add an "env" block (see Configuration).

Run from source (development)

git clone https://github.com/zhangzhongnan928/mcp-blockchain-server.git
cd mcp-blockchain-server
npm install      # installs and builds (via the prepare script)

Then point the client at the build instead of npx:

{ "command": "node", "args": ["/absolute/path/to/mcp-blockchain-server/build/index.js"] }

Remote / web clients (HTTP transport)

For MCP clients that connect over HTTP instead of spawning a local process, run the server in HTTP mode. It then serves the MCP endpoint and the signing page on one port:

MCP_TRANSPORT=http PUBLIC_BASE_URL=https://your-host npx -y mcp-blockchain-server

• MCP endpoint (Streamable HTTP): https://your-host/mcp
• Signing links: https://your-host/tx/<id>

Bind a public interface with HOST=0.0.0.0 (or keep the default 127.0.0.1 and put it behind a reverse proxy). When exposed publicly, set MCP_ALLOWED_HOSTS and/or MCP_ALLOWED_ORIGINS to enable DNS-rebinding protection, and front it with HTTPS and access control.

To host it as a custom connector (one-click Render, Vercel, Docker, or a quick tunnel for testing) and wire it into Claude's Add custom connector dialog, see

... View full README on GitHub