Lets go back to waterfall even harder and write the super correct and detailed design doc.
Bear in mind this is a B2B enterprise company with a mix of legacy and greenfield. And management has invested heavily into designing a robust spec/context-based workflow for using agents. Might be different elsewhere.
Personally I don't think scrums, planning, retros etc were better than kanban even before AI, at least if you have switched-on, motivated and smart people on your team. They actually made things less agile, and story-points give a false sense of predictability. Imo the crucial factor may be that AI agents are smart and switched-on (with the right context).