ADR 0003: Ordered events and frame time

Date: 2026-09-11 · Status: accepted · Implementation: see current implementation for delivered scope and remaining work.

Context

Replaying bad transitions and comparing actors requires more than mutable deck state or wall-clock timers.

Decision

All state-affecting input passes through engine validation and ordered events. Record a durable journal with a versioned initial state and execution environment. Inject a clock whose authoritative coordinate is integer output frames plus sample rate; the real-time or offline renderer advances it once audio is introduced.

Consequences

Reducers can be replayed and checked independently. Exact audio reproduction remains conditional on assets and DSP environment. External observations and model outputs must be recorded. State replay, render replay, and re-simulation have separate contracts. Journaling failures must not block the audio callback.