Like CMUnited-97, CMUnited-98 is organized around the concept of flexible formations consisting of flexible roles. Roles are defined independently of the agents that fill them: homogeneous agents (all except the goalie) can freely switch roles as time progresses. Each role specifies the behavior of the agent filling the role, both in terms of positioning on the field and in terms of the behavior modes that should be considered. For example, forwards never go into auxiliary defense mode and defenders never go into auxiliary offense mode.
A formation is a collection of roles, again defined independently from the agents. Just as agents can dynamically switch roles within a formation, the entire team can dynamically switch formations. After testing about 10 formations, the CMUnited-98 team ended up selecting from among 3 different formations. A standard formation with 4 defenders, 3 midfielders, and 3 forwards (4-3-3) was used at the beginnings of the games. If losing by enough goals relative to the time left in the game (as determined by the locker-room agreement), the team would switch to an offensive 3-3-4 formation. When winning by enough, the team switched to a defensive 5-3-2 formation.
Formations also include sub-formations, or units, for dealing with issues of local importance. For example, the defensive unit can be concerned with marking opponents while not involving the midfielders or forwards. A player can be a part of more than one unit.
For a detailed presentation of roles, formations, and units, see .