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The kernel — the pure decision core

@eigeninteractive/kernel is where every decision about a game is made: a pure function from inputs to a commit plan. It touches no platform API, so it behaves identically in every environment — which is why your hooks can be tested without a Worker, a socket or a database anywhere in sight.

commit({ game, state, roster, intent, now, rules, staleViews }) →
    CommitPlan  |  Rejected
  • intent is one of start (seed a new game), action (a player/bot move), or lifecycle (timeout / forfeit / autoForfeit).
  • rules is the game's GameRules unit for this game's schemaVersion. The kernel invokes the game's hooks but owns everything around them.
  • A CommitPlan carries: the next StateRow (version, opaque state, pending set, deadline, per-player clocks), the per-seat projected frames, the action to log, any outcomes (if the game ended), the alarm time to arm, and named effects (wakeBot, notifyTurn, notifyFinished) for the runtime to deliver post-commit.
  • A Rejected is a value, not an exception: a stable code (illegalMove, notParticipant, board_updated, …) plus a message. The DO returns it; the Worker maps it to an HTTP status.

The kernel owns four things worth calling out:

  • Timing & grace — computing the next deadline, the per-player time bank, and whether a late submission is still inside the grace window. See Timing & the deadline alarm.
  • The same-view rule — whether a stale-version action is still valid. See The game lifecycle.
  • Observation fan-out — calling computeObservation once per seat to build the frames, and enforcing that a seat's projection stays truthful about itself.
  • Rating math — OpenSkill posteriors, given priors and placements. (The application of ratings — reading priors, the CAS write — is in the DO/D1 layer; see Data & storage. Only the math is here.)
Version dispatch never happens inside game logic

The engine resolves the game's schemaVersion to a GameRules unit once, up front, and every hook it calls is already the right version. A game author never writes if (version === …). See Evolving your game.

The kernel's full API is in the @eigeninteractive/kernel reference.