Lucyd MCP server

Connect an AI agent (Claude, Cursor or any MCP client) to Lucyd, a prediction markets exchange. Ask in plain language to browse markets, read the order book, trade, close positions and collect winnings.

Lucyd currently runs on the Ethereum Sepolia testnet with test USDC.

What it can do

Example requests:

• "Show the open 1h markets and the order book of the current one"

• "Buy 10 up tokens in the current 15m market at 0.55 or better"

• "Close my position in the 5m market"

• "What are my positions and total profit this week?"

• "Cancel all my orders"

Without a wallet key the server works read-only: markets, books, trades and any wallet's public stats.

Related MCP server: polymarket-mcp

Hosted, read-only

For market data only, nothing to install: add https://mcp.lucyd.trade/mcp as a custom connector (remote MCP server, no authentication) in Claude, ChatGPT or any client that supports Streamable HTTP. It has the market data tools: markets, order books, trades, and positions and stats of any wallet address. Trading needs your own wallet key, so it works only with the local server below.

To run your own hosted copy, set LUCYD_HTTP_ADDR (for example 0.0.0.0:3006) and LUCYD_HTTP_HOSTS (the host names it answers to); the server then serves MCP at /mcp and refuses to start with a wallet key.

Install

The easiest way needs only Node.js 18 or newer: the client runs npx -y @lucyd/mcp, which downloads the binary for your system on first run and checks its SHA-256. Nothing else to install, see the configs below.

Without Node.js, download the binary for your system from data.testnet.lucyd.trade/mcp (open the latest version folder; SHA256SUMS there lists the checksums) and put it anywhere, for example ~/bin/lucyd-mcp (lucyd-mcp.exe on Windows). On macOS and Linux make it executable with chmod +x lucyd-mcp. Then use its path instead of npx in the configs below.

Or build from source with Rust:

cargo install --git https://github.com/lucyd-trade/mcp-server

Connect your agent

Replace the key with your trading wallet key. Restart the client afterwards.

Claude Code

claude mcp add lucyd -e LUCYD_PRIVATE_KEY=0xYOUR_KEY -- npx -y @lucyd/mcp

Claude Desktop: edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\).

Cursor: edit ~/.cursor/mcp.json.

Both use the same format:

{
  "mcpServers": {
    "lucyd": {
      "command": "npx",
      "args": ["-y", "@lucyd/mcp"],
      "env": {
        "LUCYD_PRIVATE_KEY": "0xYOUR_KEY"
      }
    }
  }
}

If the client on Windows cannot start npx, use "command": "cmd" with "args": ["/c", "npx", "-y", "@lucyd/mcp"].

Before the first trade

The wallet needs USDC to buy and a little Sepolia ETH to pay gas for one-time approvals and redemptions. Then ask the agent to check your wallet and approve trading, or call approve_trading directly. Trading itself costs no gas: the exchange settles fills on chain.

Settings

Safety

• The key never leaves your machine. The server signs locally and sends only signed orders and transactions.

• Use a separate wallet for the agent and keep only what you are ready to trade in it.

• The server tells the agent to ask you before trading, but that is up to the agent. Set LUCYD_MAX_ORDER_USD low, or LUCYD_READ_ONLY=true if you only want data.

How it works

The server runs locally and talks to the agent over stdio. Market data comes from the public API. Orders are signed with EIP-712 and sent to the order book over WebSocket (protocol in the API docs). Approvals and redemptions are plain transactions on Sepolia.

License

MIT