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Larry Johnson
Larry Johnson

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Give your AI agent live prediction-market data in 30 seconds (MCP, no keys, no installs)

#ai #mcp #claude #tutorial

Most "connect your AI to data" tutorials end with you managing API keys, running a local server, and debugging someone's half-maintained npm package. Here's the 30-second version instead, using the Model Context Protocol and a hosted server.

What you get

Your agent (Claude, Cursor, n8n, Make — anything that speaks MCP) gains native tools for live Polymarket data:

  • search_markets / get_market — find any prediction market + live prices
  • get_orderbook — current bids/asks
  • whale_trades — recent large trades with wallet addresses
  • top_holders — who's positioned where

So you can ask things like "What's the implied probability SpaceX closes above $2T today, and which whales disagree?" and the agent pulls real numbers instead of hallucinating stale ones.

The 30 seconds

Add this to your MCP config (Claude Desktop, Claude Code, or Cursor):

{
  "mcpServers": {
    "polymarket": {
      "url": "https://mrlarryjohnson--polymarket-mcp-server.apify.actor/mcp",
      "headers": { "Authorization": "Bearer <your-apify-token>" }
    }
  }
}
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The token is a free Apify account token. No Polymarket account, no wallet, no keys for the data source — the server is hosted and always warm (Apify Standby mode), and you pay fractions of a cent per tool call instead of a subscription.

There's a matching Web Search MCP server if you also want multi-engine web/news search tools next to it.

Why hosted MCP beats local for data tools

  1. Nothing to install or babysit — no node/python process dying on your laptop mid-session.
  2. Read-only by design — the server holds no wallet and can't trade. Your agent gets market data, not the ability to spend your money.
  3. Pay-per-call — idle costs nothing; heavy research days cost cents.

The billing rule I wish more APIs had

One decision I'd recommend to anyone building paid agent tools: never bill a failed call. An upstream timeout or rate limit raises a clear error and is not charged — never disguised as an empty result. Agents retry blindly, so silent-empty responses both corrupt the agent's reasoning AND bill the user for nothing. Fail loud, bill only verdicts.

(Same rule across the rest of my catalog — whale trackers, an email validator honest about not doing SMTP theater from datacenter IPs, a website change monitor that ships actual diffs: apify.com/mrlarryjohnson. Thanks to @apify for the Standby-mode hosting.)

Questions welcome — happy to share implementation details.

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