Runtime & toolchain
The core contracts, time, identity, compilers, checkpoints, and recovery systems.
8 documents · 43 sectionsCore contracts
Storage, systems, mutation barriers, and the contracts beneath a shared world.
Component catalog
The catalog in packages/schema/builtins.ts now defines the original 17 components plus KinematicPlatform and PlatformRoute.
Entity identity
The runtime distinguishes stable entity IDs from process-local index/generation handles.
Simulation time
Ticks, input sequences, ECS commit ticks, scheduler ticks and event sequence/tick/expiry values have the unsigned 64-bit range 0–18,446,744,073,709,551,615.
Checkpoints & replay
Simulation.checkpoint() captures the complete state used by the current simulation profile at a completed boundary.
Runtime recovery
On codex/engine-foundations, a stalled or faulted simulation worker can recover without reloading the player page.
World compiler
packages/compiler.compileWorld(world) owns, validates and freezes a deterministic manifest for the current primitive authoring format.
Build worker
services/build-worker runs the trusted prefab compiler in a separate Node process and coordinates revision-checked results.