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rules.md

Last edited by David Bloomin · ·

Trick-Taking - the shared engine

Four seats, table positions 0, 1, 2, 3 clockwise. In the partnership modules positions 0 and 2 play against 1 and 3. Partners are server-assigned and re-drawn every episode: a seed-derived permutation seatOrder maps table positions to policy slots, so a policy has a different partner from episode to episode and can never arrange to be partnered with itself. Every results array and every event is indexed by SLOT; only the renderer converts to table position.

Cards

card is 0..51. rank = card div 4 (0 = deuce ... 8 = ten, 9 = J, 10 = Q, 11 = K, 12 = A) and suit = card mod 4 (0 clubs, 1 diamonds, 2 hearts, 3 spades). In prompts a card is written rank then suit letter - 2C, 9D, 10H, JS, AS. Rank ten is written 10, never T. Euchre's deck is the 24-card subset rank >= 7.

Every hand runs exactly this sequence

  1. Deal. dealer = hand mod 4. A fresh deck is shuffled from the seed and the hand index, and the module's card count is dealt to each position clockwise starting from the position left of the dealer. Any module extra - Euchre's kitty and up-card, Oh Hell's turn-up - comes off the top of the remainder. The full deal is written to the replay: spectators see every card, seats do not.
  2. Bidding / trump-making. The module's bidding phases run one decision at a time. Every bid is public the instant it is made.
  3. Trick play. Seats play one card each, clockwise from the leader, skipping any seat sitting out.
  4. Legality of a follow - one rule, engine-wide. If the acting seat holds at least one card of the LED suit, its legal set is exactly those cards; otherwise its legal set is its whole remaining hand. Two module overlays sit on top and only two: (a) Euchre's left bower is a trump and is not a card of its printed suit, for leading, for following and for winning; (b) the lead restrictions - spades and hearts may not be led until they are broken, and no heart and not the queen of spades may be played on Hearts' trick 0. The legal set is never empty, it is computed by the same predicate the applier validates with, and it is given to the model verbatim.
  5. Trick winner. If any trump was played, the highest trump wins; otherwise the highest card of the led suit. Ranks are 2 < 3 < ... < 10 < J < Q < K < A, except that Euchre's trump suit ranks 9 < 10 < Q < K < A < left bower < right bower. The winner leads the next trick.
  6. Hand scoring. The module converts the trick record into per-position points and into a zero-sum per-slot net.
  7. Rotate and repeat until the variant's hands are all scored or an end condition fires.

What a seat sees, and what it does not

Visible: the module's rules and the current phase's legal options; its own hand; the hand number and the dealer; its own table position and, in a partnership module, its partner's alias; the trump state and whether spades or hearts are broken; every bid made this hand, in order; the current trick; every completed trick of this hand and who took it; which seats are known void in which suits; the standings; its own private notes; and the precomputed legal move set.

Hidden: every other seat's cards; the kitty and the euchre discard; every other seat's hearts pass; every other seat's notes; completed hands' card-by-card transcripts (only the running standings survive a hand boundary - the memory a cog wants must live in its own notes, which is the point); the seed; the seating permutation; the tell annotations; the audit; and every policy's real name.

There is no chat, no say field, no alerts and no side band. The only thing a seat can send its partner is a bid or a card. This is a permanent exclusion, not a deferral - it is the game.

Ending

The episode always writes results and a replay and ends in exactly one of three ways. complete - every hand was scored. deadline - the wall clock: past 55% of the episode timeout every remaining decision of the hand in progress is played by the scripted baseline, the hand finishes and IS scored, and the episode stops; past 56% the hand in progress is abandoned, recorded as a handVoid event, and excluded from the scoring. budget - the 240-model-call allowance is spent; same settle path as the soft deadline. A seat that never connects is not an end condition: after the connect timeout the game starts anyway and every unconnected slot plays the baseline.