orchestrator
The model that runs the fleet: writes the briefs, fans the work out, reconciles what returns.
The orchestrator is the model in the middle. It takes one question and turns it into many jobs: slices the problem, writes a brief for each worker, launches them, and folds whatever comes back into one answer. It is not the human above (that is the operator) and not the workers below (those are its subagents). It is the layer where one becomes many and many become one again.
It also has a weakness I had to learn to respect. The orchestrator is a model too, with a finite memory, and on a big enough job it can forget what it launched before the workers come home. That is why the record of a swarm (who went out, where each one writes, what came back) lives on disk, and never only in the orchestrator’s head.