Orchestration

The layer that decides which model, tool, or agent handles each step, and in what order.

Orchestration is the routing and control logic around the models: retries, fallbacks, cheap-model-first escalation, parallel steps, state. In production this layer, not the model, is usually what determines whether the system is reliable and affordable.

In practice: Route easy tickets to a small model, escalate ambiguous ones to a reasoning model.