Set the limits.

Without limits, the agent pads: more tone, more options, a recap you did not ask for. You spend the next turn cutting.

Limits should be countable or visible: length, format, words to avoid, things not to invent. “Be concise” is not a limit. “Twelve words” is.

You are a museum label writer. Explain why the moon has phases.
Limits: two sentences; no numbers; do not mention Earth by name; do not add a title.

After it answers, check each limit. If one broke, the limit was fuzzy or the model slipped. Say so in the next turn.

A set of limits you can tick on the page. Keep them short enough to scan before you send.