Reusable mechanism engine

The ./engine entry point provides deterministic, product-neutral algorithms that a product can compose inside its own reducer.

import {
  resolveMoves,
  runSettlementCascade,
  solveLevel,
} from '@yugao-gaos/gaos-sdk/engine';

Boundary

GAOS mechanisms own:

• canonical ordering and deterministic failure behavior;
• mutation-free planning and explicit commit order;
• convergence bounds and causal traces; and
• reusable state transitions over injected product data.

The product owns:

• its reducer and semantic adapter;
• game entities, rules content, conditions, and effects;
• legal actions, observations, scoring meaning, and tuning; and
• persistence, rendering, hosting, and publication policy.

A mechanism may report that a ray stopped or a movement claim lost. The product decides whether the cause represents a wall, character, shield, cost, or visual event.

Mechanism families

The engine includes:

• square, hex, graph, and collection layouts;
• zones, cards, information partitions, teams, and spectators;
• simultaneous movement, resource claims, portals, and arrivals;
• settlement waves, chain reactions, projectiles, pushes, gates, triggers, rays, and transport;
• seeded randomness, scoring helpers, behavior trees, and solving; and
• agent environments, transcript re-simulation, and replay helpers.

Use the mechanism reference for the contract, example, edge cases, and product responsibilities of each family.

Reducer adapter

Infrastructure depends on TickReducer, not on a product registry:

interface TickReducer<TLevel, TState, TView extends SessionView> {
  init(level: TLevel, seed: number): TState;
  advance(state: TState, inputs: readonly SubmittedAction[]): TState;
  view(state: TState): TView;
  viewFor?(state: TState, seat: string): TView;
}

The product may interpret a tick as a turn, simultaneous intent window, or fixed-rate step. The SDK advances the reducer without assigning product-level meaning.

The same adapter can power ordinary play, AgentEnvironment, authoritative sessions, solvers, and replay re-simulation. This is how GAOS avoids a separate agent or verification rules engine while leaving the rules themselves under product ownership.

Historical verification

Published evidence must remain connected to the reducer version that produced it. v0.25 verifiers can load an explicitly supplied historical adapter or a product-owned, content-addressed verifier kit containing the historical reducer and semantic mappings.

GAOS standardizes kit identity and execution. The product still decides whether to publish the code and how long to retain it, and an independent policy decides whether to trust its digest.

See the full ownership map → · Build a reducer → · Browse mechanisms →