Proactive writing assistants work best when users can customize what kind of help they get, when they receive it, and how it's presented—avoiding generic suggestions in favor of role-specific, lightweight interventions that support rather than interrupt the writing process.
This paper explores how AI agents can proactively help writers by offering customizable, higher-level cognitive support at the right moments. Researchers built and tested a tool where users configure AI 'thought partners' with specific roles and proactivity levels, then observed how writers used suggestions for ideation and self-review.