L0 — Atomic Committed

L0 denotes the atomicity level at which an artifact is irreducibly committed: a principled decision event, a designated observation, or another fact that cannot be decomposed without losing its identity as a ground commitment. L0 artifacts are committed — they carry binding force — and atomic — they are the floor of the dependency hierarchy. Downstream systems that enforce invariants depend on L0 facts, not on mutable scores or draft projections.

Not everything recorded is L0. Model output, aggregated dashboards, and human-readable renderings live at higher levels until they cross a commitment boundary and become L0 events with authority, evidence, policy, and moment attached. Promoting inference to L0 without that structure is the inference-as-fact failure mode.

Even at L0, epistemic uncertainty matters: an uncalibrated sensor may be structurally atomic yet unreliable. Class A consumers require low or medium uncertainty with appropriate reservation patterns — committed status alone is not sufficient when fidelity to ground truth is poor or uncharacterised.