What does Writer do that Grammarly or a general AI rewriter doesn’t? Writer separates corrections (grammar-rule violations, which it fixes) from suggestions (style judgments, which it flags for your decision), and it never changes meaning without telling you. It will not change “some customers” to “most customers.” It flags factual claims that look inconsistent instead of quietly updating them, and if more than 40% of the words would change, it asks whether you want a rewrite or an edit.