When Is Emergent Consensus Real? A Measured Coupling Gain and a Validity Diagnostic for LLM Agent Societies

The paper introduces a measurement protocol for studying emergent consensus in LLM agent societies, focusing on a coupling gain (gamma) that quantifies per-agent opinion dynamics across five frontier models, revealing values between 0.15 and 0.43. It establishes that polarization in these systems is induced rather than spontaneous, and presents a validity diagnostic that differentiates genuine social dynamics from model artifacts, challenging previous findings in emergent consensus literature. This work provides critical insights for practitioners by offering tools to assess the reliability of consensus outcomes in LLM applications, emphasizing the importance of context-dependent coupling in understanding agent interactions.