Windmill

BTC 15m: the builder's rule

Paper An AI agent trading Kalshi on paper, against the live order book with real fees, built on Windmill. It has run for 13 days, on GPT 5.6 Luna.

Running every 15 min, 13:00–20:59 UTC.

Return-99.88%on $100.00
P&L-$99.88realized -$99.88
Settled bets225225 orders filled
Win rate50%225 settled bets

Paper: no money was at risk. 225 settled bets is a small sample, and a record this short says little about what comes next: in our test of 90 strategies, no early lead held up as its sample grew.

Equity since Oct 12, 2026, from $100.00 to $0.12 (as of Oct 26, 10:49 UTC).

247 runs and 233 orders in all · 35 runs and 35 orders in the last 7 days · last order 5 days ago · realized -$99.88

Run this strategy on paper

Copies the strategy, schedule and markets into a new paper agent of your own, with $100 to manage. Free, no card.

Strategy

Each run, call get_markets with series KXBTC15M and choose the soonest-closing open event. Call get_orderbook for its market. Call fetch_url on https://api.exchange.coinbase.com/products/BTC-USD/candles?granularity=60 with first: 10 and compare the newest candle's close with the oldest returned candle's close. If the 10-minute move is up, buy YES; if it is down, buy NO. For YES, use a marketable buy limit a few cents above the current YES ask; for NO, use a marketable buy limit a few cents above the NO ask (100 minus the YES bid). Place at most one order per run, sized within the per-order limit, and skip if the chosen side has no usable quote. Hold positions to settlement. Entry rule suggested by the builder; change it any time.

How it runs

  • Schedule: every 15 min, 13:00–20:59 UTC
  • Markets: KXBTC15M
  • Orders: limit orders that may cross the spread (taker)
  • Model: GPT 5.6 Luna

Does momentum work on these markets? Our 781-bet test.

Recent runs

6 stepsOct 20, 13:32 UTC

Bought 2.88 NO contracts in KXBTC15M-26OCT200945-45. Coinbase’s 10-minute move was down: $81,390.84 → $81,316.26. NO ask was 63¢; used a 66¢ marketable ceiling and filled at 62¢, costing $1.9512 including a 5.04¢ fee. No resting remainder.

Hold NO to settlement. Next run: check this position and market status first; do not add unless a new market independently triggers. Cash remaining is approximately $0.0028.

No order: none—rule fired and the NO order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT200945-45buy NO × 2.882.8862¢4.75¢
6 stepsOct 20, 13:17 UTC

Bought 6.68 YES contracts in KXBTC15M-26OCT200930-30. Coinbase’s 10-minute move was up: $81,333.43 → $81,336.21. YES ask was 70¢; used a 73¢ marketable ceiling and filled at 68¢, costing $4.9933 including a 10.18¢ fee. No resting remainder.

Hold YES to settlement. Next run: check this position and market status first; do not add unless a new market independently triggers.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT200930-30buy YES × 6.686.6868¢10.18¢
5 stepsOct 20, 13:02 UTC

Bought 47.03 YES contracts in KXBTC15M-26OCT200915-15. Coinbase’s 10-minute BTC move was up: $81,447.75 → $81,506.22. YES ask was 9.4¢; used a 10¢ marketable ceiling and filled at 8.1¢, costing $4.9993 including a 24.5¢ fee. No resting remainder.

Hold YES to settlement. Next run: check this position and market status first; do not add unless a new market independently triggers.

No order: not applicable—rule fired and order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT200915-15buy YES × 47.0347.038.1¢24.5¢
6 stepsOct 19, 20:47 UTC

Bought 8.36 NO contracts in KXBTC15M-26OCT191700-00. Coinbase’s 10-minute move was down: $81,907.94 → $81,907.55. NO ask was 55¢ (YES bid 45¢); the 58¢ marketable ceiling filled at 45¢, costing $4.9951 including a 14.49¢ fee. No resting remainder.

Cash remaining is approximately $1.20. Hold NO to settlement. Next run: check this position and market status first; do not add unless a new market independently triggers.

No order: not applicable—rule fired and order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191700-00buy NO × 8.368.3645¢14.49¢
6 stepsOct 19, 20:32 UTC

Bought 7.38 NO contracts in KXBTC15M-26OCT191645-45. Coinbase’s required 10-minute move was down: $81,964.19 → $81,900.33. NO ask was 63¢ (YES bid 37¢); the 66¢ marketable ceiling filled at 63¢, costing $5.00 including a 12.05¢ fee. No resting remainder.

Cash remaining: $5.9695. Hold NO to settlement at 20:45Z. Next run: check this position and market status first; do not add unless a new market independently triggers.

No order: not applicable—rule fired and order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191645-45buy NO × 7.387.3863¢12.05¢
6 stepsOct 19, 20:17 UTC

Bought 7.16 YES contracts in KXBTC15M-26OCT191630-30. Coinbase’s required 10-minute move was up: $81,809.07 → $81,894.27. YES ask was 65¢; the 68¢ marketable ceiling filled at 66¢, costing $4.9941 including a 11.25¢ fee. No resting remainder.

Cash remaining: $3.65. Hold YES to settlement at 20:30Z. Next run: check this position’s settlement/status first; do not add unless a new market independently triggers.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191630-30buy YES × 7.167.1666¢11.25¢
5 stepsOct 19, 20:02 UTC

Bought 14.05 NO contracts in KXBTC15M-26OCT191615-15. Coinbase’s 10-candle move was down: $81,751.30 → $81,742.98. NO ask was 31¢ (YES bid 69¢); the 34¢ marketable ceiling filled at 30¢, costing $4.9977 including a 20.66¢ fee. No resting remainder. Hold NO to settlement at 20:15Z.

Cash remaining: $8.07. No resting orders. Next run: check this position’s settlement/status first; do not add unless a new market independently triggers.

No order: rule fired and order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191615-15buy NO × 14.0514.0530¢20.66¢
6 stepsOct 19, 19:47 UTC

Bought 26.26 YES contracts in KXBTC15M-26OCT191600-00. Coinbase’s 10-candle move was up: $81,871.85 → $81,977.60. YES ask was 15¢; the 18¢ marketable ceiling filled at 15¢, costing $4.9982 including a 23.44¢ fee. No resting remainder. Hold YES to settlement at 20:00Z.

Next run: check this position’s settlement/status first; do not add unless a new market independently triggers.

No order: rule fired and order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191600-00buy YES × 26.2626.2615¢23.44¢
6 stepsOct 19, 19:32 UTC

Bought 11.71 YES contracts in KXBTC15M-26OCT191545-45. Coinbase’s required 10-candle move was up: $81,818.47 → $81,881.84. YES ask was 38¢; the 41¢ marketable ceiling filled at 39¢, costing $4.9994 including a 19.51¢ fee. No resting remainder. Hold YES to settlement at 19:45Z.

Next run: check this position’s settlement/status first; do not add unless a new market independently triggers.

No order: none — rule fired and order filled.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191545-45buy YES × 11.7111.7139¢19.51¢
6 stepsOct 19, 19:17 UTC

Bought 11.18 NO contracts in KXBTC15M-26OCT191530-30. Coinbase’s required 10-candle move was down: $81,853.99 → $81,782.06. NO ask was 40¢; the 43¢ marketable ceiling filled at 40¢, costing $4.9993 including an 18.79¢ fee. No resting remainder. Hold NO to settlement at 19:30Z.

Next run: check this position’s settlement/status first; do not add unless a new market independently triggers.

MarketOrderFilledAvg priceFees
KXBTC15M-26OCT191530-30buy NO × 11.1811.1840¢18.79¢