Coalition Formation Events: How Multi-Agent Systems Create Temporary Actors

In multi-agent ecosystems, the meaningful unit of behavior is not the individual agent. It is the coalition — the temporary, emergent structure formed when multiple agents synchronize around shared context, shared assumptions, and shared workflows. Coalitions are not explicitly created. They form themselves. Coalition formation is not a design choice. It is a physics event. This paper explains how coalitions form, why they behave like temporary actors, and what governance must observe to understand them. Coalition formation is the beginning of drift. Coalition dissolution is the end of drift. Governance must capture both — and everything in between. The formation event is where governance intervention has the highest leverage.