Material agency: operationalizing the living/nonliving interface in engineered materials.

The label 'engineered living materials' groups devitalized mycelium composites with metabolically active biosensors, applying shared metrics to systems with fundamentally different failure modes, safety profiles, and engineering requirements. This forum proposes a four-class operational taxonomy, a Maximum Agency Potential classification principle, and a minimum reporting standard that classify systems by biological agency dependence during use.