@pmxt/mcp

@pmxt/mcp

MCP server that exposes the PMXT unified prediction market API as tools for Claude and other AI agents.

One tool per API method. Same interface regardless of venue -- Polymarket, Kalshi, Limitless, Probable, Baozi, Myriad, Opinion, Metaculus, Smarkets, and more.

Quick start

Add to your Claude Desktop config (claude_desktop_config.json):

{
  "mcpServers": {
    "pmxt": {
      "command": "npx",
      "args": ["-y", "@pmxt/mcp"],
      "env": {
        "PMXT_API_KEY": "pmxt_live_..."
      }
    }
  }
}

Or run directly:

PMXT_API_KEY=pmxt_live_... npx @pmxt/mcp

Get an API key at pmxt.dev/dashboard.

Modes

The MCP server doesn't run prediction market logic itself -- it forwards every tool call to a PMXT API server over HTTP. Where that server lives depends on the mode:

Hosted -- Set PMXT_API_KEY and the server calls https://api.pmxt.dev. No local setup required; the hosted service manages exchange connections, caching, and rate limits for you.

Local (sidecar) -- If no API key is set, the server assumes you're running the PMXT core server locally on http://localhost:3847. This is useful for development, self-hosting, or when you want full control over the runtime. See the pmxt core repo for how to run the server.

You can point at any PMXT-compatible server by setting PMXT_API_URL explicitly.

Environment variables

Variable	Description
PMXT_API_KEY	API key for the hosted PMXT service
PMXT_API_URL	Override the API base URL (defaults based on mode)

Tools

Every tool requires an exchange parameter (e.g. polymarket, kalshi, limitless). Read-only tools are safe to call freely. Order-related tools (createOrder, submitOrder, cancelOrder) require explicit user confirmation -- they spend real money.

Market discovery: fetchMarkets, fetchMarketsPaginated, fetchEvents, fetchEvent, fetchMarket

Order book & pricing: fetchOrderBook, fetchTrades, fetchOHLCV, getExecutionPrice, getExecutionPriceDetailed

Trading: buildOrder, createOrder, submitOrder, cancelOrder

Account: fetchBalance, fetchPositions, fetchOpenOrders, fetchClosedOrders, fetchAllOrders, fetchOrder, fetchMyTrades, loadMarkets

How it works

The server translates MCP tool calls into HTTP requests to the PMXT REST API:

• Agent calls a tool (e.g. fetchMarkets) with flat { exchange, limit, query } input
• The server reconstructs positional arguments from the flat input using embedded arg specs
• Sends POST /api/{exchange}/{method} with { args: [...] } to the PMXT API
• Returns the JSON response to the agent

Auto-generation pipeline

The tool definitions in src/generated/tools.ts are not hand-written. They are generated from the PMXT core OpenAPI spec by scripts/generate-tools.cjs.

The full pipeline runs automatically on every PMXT release:

• A new version tag (v*) is pushed to the pmxt core repo
• The sync-mcp.yml GitHub Actions workflow triggers
• It clones this repo, copies the latest spec files from core into spec/:
  • core/src/server/openapi.yaml -- full API spec (endpoints, parameters, response schemas)
  • core/src/server/method-verbs.json -- HTTP verb and positional argument metadata per method
• Runs node scripts/generate-tools.cjs to regenerate src/generated/tools.ts
• Bumps package.json to match the core version
• Commits, tags, and pushes to this repo
• Publishes to npm with npm publish --provenance --access public

What the generator does:

• Reads both spec files
• Skips streaming/internal methods (watchOrderBook, close, healthCheck, etc.)
• Flattens complex parameters into flat MCP tool input schemas
• Embeds ArgSpec metadata so the server can reconstruct positional args at runtime
• Adds annotations (readOnlyHint, destructiveHint, idempotentHint) per tool
• Marks order-related tools with a credentials input property

To regenerate locally:

npm run generate

Development

npm install
npm run generate   # regenerate tools from spec/
npm run build      # compile TypeScript

License

MIT