@game-hub/kernel

The tiny shared core of Game Hub, a self-hosted board-game platform: the primitives every game package and both hosts (backend + UI shell) build against, and nothing else.

What's in it

• . — GameError, MoveRecord, Viewer, record(), makeSeating, GameEndState, the GameModule/ModuleContext contract (with structural host interfaces, so the kernel imports no host), KERNEL_CONTRACT_VERSION, and the seeded-setup helpers shuffle(items, rng?) / mulberry32(seed) (1.2.0 — an engine and its tests need these, so they are not on ./bot).
• ./bot — runBotLoop and the bot-driver helpers, written entirely against the generic contract surface.
• ./client — the GameClient/BoardProps contract the UI shell loads a game's board through, plus the transport DTOs a client names (GamePayload, GameIdentity, GameMessage). Type-only React usage; React is not a runtime dependency.

The shared chrome a board renders inside (turn banner, activity feed, end screen, buttons) is a separate package, @game-hub/ui-kit — it needs React at runtime, which this package deliberately never does.

The contract version

The package's major version is the kernel contract version. A game module declares kernelContract (import KERNEL_CONTRACT_VERSION, never a literal); a host refuses to register a game built against a different contract. Additive optional hooks are minor bumps; any change to a required member's meaning is a major.

Writing a game

A game is one npm package with four subpath exports — ./engine (pure rules), ./module (backend seam), ./client (UI seam), ./bot (optional AI) — peer-depending on this kernel. The full recipe, seam rules, and conformance expectations live in the platform repo's docs/game-creation.md and docs/design-patterns.md.

Game engines built on this kernel are pure: no Date, no Math.random, no mutation — randomness is injected at setup and per action, so every game is deterministic and replayable.