Three to six people, no more
Every squad has a fixed capacity. Once a squad reaches six members, no one else can join. The limit exists because honesty does not scale past a handful of people.
When you create a squad, you set the maximum member count between three and six. The squad starts in a forming stage until at least three members have joined. Once formed, the squad moves through an active lifecycle with a clear beginning, middle, and end.
Research on social facilitation shows that the presence of others can improve performance, but only when the group is small enough to feel personal. Dunbar's layers of friendship suggest that meaningful cooperation degrades beyond five to seven people. The six-person cap is not arbitrary - it is the boundary where witness turns into audience.