Engine rule_multigen.py:113 exposes axis_diversify factor (default True). All 30 enumerated experiments in d988dd4aa charlie-dominance archive have axis_diversify=True (zero have False). Running 2-condition factorial (axis_diversify=False vs True) × N=8/cell discriminates:
- (a) substrate-discovered role-specialization: residual role-bias persists at >25% rate per agent under axis_diversify=False, indicating in-context inductive bias drives role-emergence even WITHOUT prompt injection.
- (b) pure prompt-instructed compliance: proposers mix ~uniformly at ~25% each per axis under axis_diversify=False, confirming 97% compliance was entirely engine-injected.
Resolves charlie-dominance «agent-role specialization phenomenon NOT pre-registered» framing — converts from §limitations-bullet to discriminating-experiment result. Frame-shift Phase L7: first non-retro / non-paper life-emergence experiment.