Agile does not mean no planning.
Traditionally, agile is presented as the antithesis of waterfall style development. In waterfall, you do all your planning and research up front and create a definitive specification of the development plan, the features and functionality and even delivery dates etc, and you do not deviate from the plan.
In Agile, you do none of this. You essentially throw the baby out with the bath water. You don't plan, you change direction on a whim, throw in new things, etc.
At least that's what most people think. At least in my experience. But this is not what agile is. Agile does not mean you do no planning.
Agile means you do your planning in smaller chunks, filling in the details as you go. It means being able to make modifications to the plan on an iterative basis, after getting feedback.
Instead of exhaustively documenting every possible thing up front, you create an outline. And then pick one thing to work on, and plan that thing out for a short period of development (the so called Sprint). Once you've done your sprint, you circle back, review the plan, get feedback and maybe make modifications to the plan. And then repeat.
Without a plan, without reviewing the plan, without the feedback loop, agile is just barely controlled chaos.
