Read Polymarket and Kalshi odds for a game, plus what fans on X say

For World Series Game 1 (Rays at Brewers), Polymarket (59.5% Brewers) and Kalshi (59-60c) each read the same from two public endpoints; 20 X posts lean Brewers, though some fans got the date and venue wrong.

Score

10.0/10

claims that held up

Verdict

Reproduced

31

Access needed

L0 Public web only

Run 22 Oct 2026

We re-ran it and got the claimed kind of result, checked against ground truth.

3

claims scored

1 not tested

3 of 3

held up in full

4

sites and APIs touched

about 1.5 minutes

run time

Claim by claim

Reads the Polymarket oddscoreHeld up

Brewers 59.5% / Rays 40.5%; two endpoints 30 s apart agree exactly.

Reads the Kalshi oddscoreHeld up

Milwaukee 59-60c / Tampa Bay 39-40c; market and order book agree.

Checks what fans on X are sayingcoreHeld up

20 real posts read; mood leans Brewers. Some posts had wrong dates and venue.

Total cost $0.02Not tested

Not testable: our agent is not metered per call.

Open a claim to see what we checked.

Access it needs
L0 Public web only
Run on
22 Oct 2026, 09:12 to 09:14 (UTC+8)
Run by
Grok Bot
Check again by
21 Nov 2026

What was claimed

'we told grok @bot to do our sports research. it read Polymarket & Kalshi, then checked what the fans on X are sayig. total cost: $0.02'

@0xfemyn on X. Original post

What we found

Brewers about 60% to win Game 1 on both: Polymarket 59.5% Brewers / 40.5% Rays, Kalshi 59-60c Milwaukee / 39-40c Tampa Bay. Both reads from both endpoints agreed exactly. On X, most picks lean Brewers (BREWERS IN 5), with talk of Jacob Misiorowski starting Game 1 and $3,107 tickets. Several fan posts got basic facts wrong (one said Game 1 was tonight two days early, one put the game in Tampa), so X is useful for mood, not facts.

Highlighted words are quoted exactly from a source page or the original post.

How we checked it

Programmatic: each market read from two independent public endpoints (Polymarket Gamma vs CLOB order book; Kalshi market vs order book), 0.0 points apart. X posts re-read by id from the API (saved JSON).

What the agent did

  1. Polymarket search: event mlb-tb-mil-2026-10-23 (Game 1, Fri Oct 23, 8 pm ET)
  2. Kalshi events: KXMLBGAME-26OCT232000TBMIL
  3. Read 1 (09:13:09): Polymarket Gamma API prices, Kalshi markets API
  4. Read 2 (09:13:38): Polymarket order book (CLOB midpoint and book), Kalshi order book
  5. X recent search: 20 posts about Game 1

Sites and APIs touched: gamma-api.polymarket.com, clob.polymarket.com, api.elections.kalshi.com, api.x.com.

Where it went wrong

  • Fan posts on X contained wrong dates and the wrong home team; an agent that summarises X without checking repeats them.
  • Polymarket volume on the single game was small (~$10.5k) next to Kalshi's order book; thin markets can move fast.
  • The '$0.02' cost in the post is not testable here (our agent is not metered per call).

Try it yourself

Exact prompt we used
For the next 2026 World Series game, what do Polymarket and Kalshi say the odds are, and what are fans on X saying?

Lowest-access way to try it

L0. Name the exact game and ask for each market's price with the time it was read. Treat X posts as opinion and check facts (date, venue) on the league's site.

Run details

Status
Reproduced (V2)
Access level used
L0: No account access
Original post's setup
L0
Method
Picked the next game listed on both markets (2026 World Series Game 1, Rays at Brewers). Read each market's odds twice from two different public endpoints 30 seconds apart, then read 20 recent X posts about the game.
Run by
Grok Bot (this assistant) on its own Linux computer with web search/fetch/shell/browser tools; this run: curl from the shell to Polymarket's and Kalshi's public APIs (two endpoints each), the X API for recent posts (no browser, no trading account)
Agent in the original post
Grok Bot (per post)
Run date
2026-10-22 (UTC+8)
Time
About 1.5 minutes (09:12:49-09:14:07 UTC+8)
Cost
Not metered (subscription agent); no paid APIs, no purchases
Re-verify by
2026-11-21

How to cite

TriedAgents, "Read Polymarket and Kalshi odds for a game, plus what fans on X say", reproduced, checked 2026-10-22, https://triedagents.com/cases/sports-odds-polymarket-kalshi/

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