Turn
Domain: DSH Fundamentals
Motivation
A turn is one iteration of the agent loop: at a turn boundary the driver opens a durable turn, claims pending input, and runs one or more steps — each step assembles the prompt and tools, projects runtime context, calls the model, and executes any requested tool calls before the next step. A turn ends when the model produces no further tool calls or the loop is cancelled. Cancellation is cooperative and preserves streamed text already delivered to the user.
Concrete Example
In the session log, each turn is bracketed by durable turn open/close events, and dsh-agent-loop owns the turn/step machine.
Analogy
It is one round of a conversation: you speak, it acts, it speaks back — then the round closes.