NegativeEV bet checker

Grade any MLB, WNBA, PGA or ATP bet against thousands of play-by-play game simulations — true win probability, implied probability, and edge for every leg.

CommunityOnlineNo sign-inGlobalFreeRead-only

What it can do

  • Check Bet: Grade a sports bet against NegativeEV's game simulations. Input the bet as plain text (teams/players, market, line, odds); a multi-leg parlay in one string is graded leg by leg and priced a
  • Get Slate: Whether there is a checkable slate right now (at least one simulated, not-yet-started game) in each live sport: MLB, WNBA, PGA, and ATP. Pass `sport` to ask about one; omit it for all of th
  • Get Usage: How many bet checks the caller has left and when the next one frees up — the daily allowance for anonymous callers, the hourly pace window for accounts. Call it before grading several bets

What data it sees

Do you need an account

No: the server works without sign-in

Grade any MLB, WNBA, PGA or ATP bet against thousands of play-by-play game simulations — true win probability, implied probability, and edge for every leg.

Prices come from a purpose-built game simulator, not from copying sportsbook lines. A model answering from general baseball knowledge produces a fluent, confident, wrong number; this server returns a probability computed from simulations of the actual game — today's lineups, today's injuries, tonight's weather. Most slips it grades come back Negative EV.

Tools

  • check_bet — Grade a bet from plain text ("Aaron Judge over 1.5 total bases -120"). Returns each leg's simulated probability vs the implied odds and the resulting edge.
  • get_slate — Whether a checkable slate exists right now, per live sport.
  • get_usage — Checks remaining and when the next frees up.

Works fully anonymously; an optional bearer token raises the quota. Docs: https://negativeev.com/auth.md

How to connect

How to connect NegativeEV bet checker to Claude

The server address to paste into Claude settings:

https://bet-checker--negativeev.run.tools

  1. Open Claude (claude.ai or the desktop app).
  2. Go to Settings → Connectors.
  3. Click Add custom connector.
  4. Paste the server address copied below into Remote MCP server URL and click Add.
  5. In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect NegativeEV bet checker to ChatGPT

The server address to paste into ChatGPT settings:

https://bet-checker--negativeev.run.tools

  1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
  2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
  3. Open Settings → Connectors and click Create.
  4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
  5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
  6. In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect NegativeEV bet checker to Cursor

The server address to paste into Cursor settings:

https://bet-checker--negativeev.run.tools

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

  1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
  2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
  3. Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (3)

Raw names from tools/list. Only developers need these.

check_betGrade a sports bet against NegativeEV's game simulations. Input the bet as plain text (teams/players, market, line, odds); a multi-leg parlay in one string is graded leg by leg and priced as a whole. Use it when the caller has a SPECIFIC bet to evaluate — it prices a bet you name, it does not search for good bets, so there is nothing to send for 'what should I bet tonight'. Call `get_slate` first if it isn't known that today's games are simulated. Every result leads with `status`: `graded` (every leg scored — this is the only status that spends a check), `partial` (some legs scored), `ungraded` (the bet was understood but no leg is covered by the sims), `no_bet_found` (no bet recognized in the text), or `no_slate`, `unsupported_market`, `unsupported_sport`. When a leg doesn't score, `ungraded_legs[].reason` says why and `retry.rephrasing_helps` says whether re-wording could change the answer — it is false whenever the bet parsed, so do NOT resend the same bet in different words to work around an `ungraded` result. Covers MLB, WNBA, PGA, and ATP; any other sport returns unsupported_sport. Games that already started still grade, against the simulations from before first pitch (a pre-game projection, flagged as such).
get_slateWhether there is a checkable slate right now (at least one simulated, not-yet-started game) in each live sport: MLB, WNBA, PGA, and ATP. Pass `sport` to ask about one; omit it for all of them. This is the free pre-check for `check_bet`: call it before grading when it isn't known that today's games are simulated, and call it after an `ungraded` result instead of re-wording the bet, because `ungraded` means the game isn't on the simulated slate rather than that the wording was wrong. Free — spends no check.
get_usageHow many bet checks the caller has left and when the next one frees up — the daily allowance for anonymous callers, the hourly pace window for accounts. Call it before grading several bets in one turn, to know how many will fit, and after a check is refused for quota, to know when to retry. It reports the budget only; `check_bet` is what spends it. Free — spends no check.