Definition
An orchestrator is the component or role that admits work, assigns it, coordinates dependencies and concurrency, tracks state, handles retries, and determines handoffs or completion. It is responsible for the lifecycle of the run, even when other agents choose how to perform individual tasks.
An orchestrator can be ordinary code: a queue, scheduler, state machine, or workflow engine. A model is useful when coordination requires interpreting ambiguous work, but it should not control security-sensitive transitions merely because it wrote the plan.
The role needs durable state and idempotent operations. After a restart, it should know which work completed, which effects may already have occurred, and which tasks are safe to retry.
Distinguish it from nearby terms
An orchestrator coordinates work. An agent performs goal-directed actions. A supervisor agent can do both, but combining the roles also combines their failure and authority boundaries.
Check your understanding
An orchestrator times out while a payment worker succeeds. If it blindly retries the task after restart, the customer may be charged twice. Durable outcome state matters more than whether the coordinating component uses a model.