Coalition Drift Signatures: How to Detect Multi-Agent Divergence

Coalition drift is the most dangerous form of drift in multi-agent ecosystems because it is coherent. Agents don’t just drift individually — they drift together, reinforcing each other’s divergence. The challenge is not that coalition drift is subtle. The challenge is that coalition drift is plausible. This paper outlines the signatures — the detectable fingerprints — of coalition-level divergence. These signatures are not behavioral anomalies. They are pattern-level artifacts that emerge when multiple agents synchronize around the same incorrect assumption. Detecting coalition drift requires looking at patterns, not individuals.