Agile is humility. You do not have a crystal ball:- the unexpected can, (and frequently does) happen in this most uncertain of worlds.
Agile is old-fashioned, conservative decision making. Do not take risks that you can avoid.
Agile is the art of not committing to a course of action when you do not know what the future will bring. Postpone risky decisions, wait until you have more information before committing time and resources.
Agile is risk-aware prioritization. Schedule simple, low-risk activities that give you feedback and information before complex, high-risk activities that could go wrong.
Agile acknowledges the limits of prediction, and seeks to improve responsiveness and the capability to react quickly to external changes.
Agile is neither lightweight nor easy. You can be bad at being Agile just as you can be bad at any other activity.
Technology can help. The ability to respond quickly to external changes is an organizational capacity that must be built and nourished, just like any other capability that you want your organization to have.
You cannot plan change, but you can plan for change.