A process orchestrator is the coordination layer that holds a cross-system goal and routes work to the scoped agents that execute it. It understands that a renewal touches CRM, billing, and legal. It holds write-access to none of them. The specialists mutate; the orchestrator sequences the work and decides what moves next.
Why this layer has to exist, and the three hard problems it creates (context handoff, transaction ownership, rollback), is the argument in orchestrating-scoped-agents.