This article, published in Social Innovations Journal, presents a heuristic for generative AI integration in writing instruction. Developed through the Digital Discourse Project—a 5-year study of a research–practice partnership with the National Writing Project—the heuristic outlines five categories (resistance, support, expression, understanding, and critique) to help educators think about the use of GenAI in writing assignments. Importantly, the article explores what each category and purpose is in classroom contexts, including lessons and instructional strategies for teacher educators and teachers to try in their own classrooms. Examples include using AI chatbots to brainstorm ideas, comparing AI-generated versus human-written text, and analyzing bias or ethics in AI tools. Although this article is written with teacher educators and teachers in mind, the authors argue that the heuristic can support policymakers, edtech developers, social investors, and nonprofits in their use of AI in teaching and learning.