T3 squad leads now use dedicated senior roles instead of sharing architects with T2: - T3 backend: backend-architect → senior-backend-developer - T3 frontend: frontend-architect → senior-frontend-developer Clean tier separation: T2 = architects (design) T3 = senior devs (lead + implement-or-delegate) T4 = developers (pure implementation) Depends on: coding-with-hans-heinemann/agency-agents#2