A private wiki keeps notes, questions, ideas and decisions in one place, linked as you think them through. With an agent's help, a conversation becomes a page, an earlier decision turns up again, or a long draft splits into sections.
A topic gets a page; a thought or source, a block within it. A discussion stays next to its conclusion. A book can take a page per chapter, keeping the outline and drafts together while an agent helps revise them. To try it, first steps has a ready-made task.