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Game Rules: Crash Minimal

Single source of truth for how Crash Minimal plays. Player-facing terms, operator-facing SLA, and cert-lab (GLI-11) submission all cite this document.

Paired documents:

Any change to this document is a regated change, see change-management.md.

Submission status: pre-cert. This plugin has not been submitted to any cert lab. The rules below are derivable from games/crash-minimal/src/ as of the most recent commit; the RTP regression, test vectors, and independent math review remain open before GLI-11 submission.

1. Game overview

Crash Minimal is a provably-fair single-multiplier crash game. Each round rolls a multiplier ≥ 1.00× with a long right tail. The player commits to a cashout multiplier before the round starts; if the rolled crashMultiplier reaches or exceeds the player's cashoutMultiplier, the player wins stake × cashoutMultiplier (minus operator commission); otherwise the stake is lost.

This plugin ships as the second reference implementation of the GamePlugin contract (see B2B_ROADMAP.md §4), its purpose is to validate the plugin seam against a continuous-outcome game, as distinct from Ketapola Dice's discrete LOW/HIGH shape.

2. Round lifecycle

Same plugin-driven state machine as every other game: PENDING → BETTING_OPEN → ROLLING → RESULT → SETTLED / VOIDED. Plugin-specific observations:

  • Only one selection shape: { cashoutMultiplier: number } with 1.01 ≤ cashoutMultiplier ≤ 10_000 (games/crash-minimal/src/selection.ts).
  • No manual cashout in this minimal variant, the commit is the cashout. A richer variant with live cashout would be a separate plugin.

3. Outcome

The round produces a single crashMultiplier ∈ [1.00, maxMultiplier] with two decimal precision. Derivation is in rng-spec.md §6; the brief form:

hmac = HMAC_SHA256(serverSeed, clientSeed + ':' + nonce)
u_raw = first 52 bits / 2^52, uniform[0, 1)
if u_raw < houseEdge:
  crashMultiplier = 1.00, house-bust branch
else:
  u = (u_raw - houseEdge) / (1 - houseEdge)
  crashMultiplier = floor(100 / (1 - u)) / 100, two-decimal
clamp to [1.00, maxMultiplier]

4. Settlement

From games/crash-minimal/src/settle.ts:

  • Win (crashMultiplier ≥ cashoutMultiplier): gross = stake × cashoutMultiplier, payout = max(0, gross − commissionMicro).
  • Loss (crashMultiplier < cashoutMultiplier): stake is lost, no payout.

Commission is a flat commissionMicro per bet, matching the OperatorGameConfig shape used by every game.

5. Configuration parameters

Per-operator-per-currency, stored on OperatorGameConfig.configJson and validated by the plugin at engine startup (games/crash-minimal/src/config.ts):

Parameter Type Default Meaning
houseEdge number ∈ [0, 1) 0.01 Pre-roll bust probability, sets RTP to 1 − houseEdge.
maxMultiplier number ≥ 1.01 1000 Hard cap on crashMultiplier to bound the client animation and wire payload.

6. Session lifecycle

Identical to Ketapola Dice, see ketapola-dice/docs/game-rules.md §8 for the platform-wide contract. One gameCode (crash-minimal) per session; serverSeed / clientSeed / nonce drive RNG; seed rotation mechanics unchanged.

7. Source of truth

Question Answer lives in
Rules (this doc) games/crash-minimal/docs/game-rules.md
Math par-sheet.md
RNG rng-spec.md
Outcome code games/crash-minimal/src/outcome.ts
Settlement code games/crash-minimal/src/settle.ts
Platform wallet contract docs/wallet-api.md