RFC-0013: Time and Determinism

Status: Draft | Version: 0.1.0

1. Time

Kernel time supports Real, Simulation, Replay and Prediction domains.

pub struct SimTime {
    pub tick: u64,
    pub nanos: i64,
}

2. Clock rules

World simulation must not read wall-clock time implicitly. Wall-clock access is an explicit external input.

3. Fixed-step

Deterministic physics uses a declared fixed timestep. Variable-step execution is legal only where semantics permit it.

4. Determinism levels

BestEffort, Reproducible, StrictDeterministic.

5. Strict mode

Requires stable iteration order, deterministic scheduling/reduction, explicit random seeds, controlled floating-point behavior and deterministic message ordering.

6. State hash

A canonical state hash is computed from schema, entity IDs, selected components and canonical numeric representation.

7. Replay

Replay consists of initial snapshot + schema set + external input/event stream + configuration.

8. Acceptance

Strict replay of the same artifact and inputs must reproduce the same state hash at every declared checkpoint.