The person accountable for scope, schedule, and communication — keeping the plan honest, flagging risks early, and being the client's single point of contact.
On a team of more than three, coordination becomes a job. Without it, developers manage the client directly and the first casualty is an accurate view of where things stand.
We assign one manager as your point of contact, with status reported against the plan rather than as activity, and we say when a date is at risk early, while options still exist.