What makes a good Instagram caption?
Instagram cuts captions after the first lines in the feed, so the first sentence decides whether people read on. Give them a reason to stop: a question, useful information, a promise.
The rest follows a simple structure the generator applies: hook, two or three lines of context, call to action. The technical limit is generous, 2,200 characters according to Meta's documentation, but a useful caption is almost always much shorter.

