Prediction Market Rule Check

Don't lose a winning trade to the small print — risk-score Polymarket and Kalshi settlement rules before you bet.

For prediction-market traders and trading bots. Free check on any Polymarket market; subscribers get full rule text, Kalshi tickers and scans of the riskiest live markets in their AI agent.

Tools

• rule_check (free) — FREE. Risk-score the settlement rules of a Polymarket market (slug or search words): flags discretion, vague sources, cancellation and deadline traps. Top 2 markets.
• rule_check_full (Pro) — PRO. Full rule text + resolution source + all flags for up to 10 Polymarket markets matching a slug or search.
• kalshi_check (Pro) — PRO. Risk-score a Kalshi market's rules by ticker (rules_primary + rules_secondary).
• scan_risky (Pro) — PRO. Scan the top live Polymarket markets by volume and list the ones with the riskiest settlement wording.

Live free example

rule_check {"market":"bitcoin"}

{
  "results": [
    {
      "venue": "Polymarket",
      "id": "will-bitcoin-reach-91k-on-october-14-2026",
      "question": "Will Bitcoin reach $91,000 on October 14?",
      "end": "2026-10-15T04:00:00Z",
      "url": "https://polymarket.com/market/will-bitcoin-reach-91k-on-october-14-2026",
      "risk_score_0_10": 1,
      "risk": "low",
      "flags": [
        {
          "flag": "Time-zone sensitive deadline — check the exact cut-off",
          "weight": 1
        }
      ]
    },
    {
      "venue": "Polymarket",
      "id": "will-bitcoin-reach-90k-on-october-14-2026",
      "question": "Will Bitcoin reach $90,000 on October 14?",
      "end": "2026-10-15T04:00:00Z",
      "url": "https://polymarket.com/market/will-bitcoin-reach-90k-on-october-14-2026",
      "risk_score_0_10": 1,
      "risk": "low",
      "flags": [
        {
          "flag": "Time-zone sensitive deadline — check the exact cut-off",
          "weight": 1
        }
      ]
    }
  ],
  "pro": "Full rule text, Kalshi markets and scans of the riskiest live markets: https://prediction-rules-mcp.donniertf.workers.dev/buy",
  "disclaimer": "Automated wording heuristics, not a prediction or financial advice. Always read the full market rules yourself; venues can clarify rules after you trade. Check prediction markets are legal where you live."
}

Connect (MCP)

Add https://prediction-rules-mcp.donniertf.workers.dev/mcp to Claude, Cursor or any MCP client (Streamable HTTP, no login for the free tier). Subscribers pass access_token or Authorization: Bearer.

Important

Automated wording heuristics, not a prediction or financial advice. Always read the full market rules yourself; venues can clarify rules after you trade. Check prediction markets are legal where you live.

Data sources & licences

• Polymarket Gamma public API
• Kalshi public trade API (market data)

For AI agents

llms.txt · server card · pricing.json · POST /checkout → checkout URL · GET /token?session_id= → access token.

More UK data MCPs

See the whole fleet (Companies House, Land Registry, planning, tenders and more), plus the £1.99 / £3.99 pack bundles: bundles · GitHub hub.

Contact & cancelling

Questions, refunds or cancelling: dmorrisonwebdesign@gmail.com. Run by Donnie Morrison, UK. Payments by Stripe; we never see card details.