A multi-agent system without an orchestrator is just a collection of agents. Each one is capable, but none of them coordinated. They might all be excellent at their individual jobs - searching the web, writing code, calling APIs - but without something deciding what gets done, in what order, by whom, and what to do when a result comes back wrong, the system does not behave like a system. It behaves like a group project with no project manager.
The orchestrator is the project manager. Its job is not to do the work. Its job is to make sure the work gets done - and that is a harder, more subtle problem than it sounds.
What an orchestrator is responsible for
An orchestrator does four things, and only these four things:
1. Decompose the goal. Turn a high-level objective into a concrete set of subtasks. This is a planning problem, not an execution problem. The orchestrator decides what needs to happen, not how to do it.
