With the widespread application of Generative AI in game content creation, AI-UGC (Artificial Intelligence-Assisted User Generated Content) is gradually transforming traditional player creation processes and platform ecosystems. This article focuses on the types of functions provided by AI tools in mainstream game creation platforms, constructing a “Generation Object-Interaction Granularity-Algorithm Role” Three-dimensional Classification Model. Using Roblox, Fortnite Creative 2.0, Dreams, and Core Games as case studies, it systematically categorizes the application characteristics of seven representative AI tools through the content analysis method and function matrix comparisons. The research findings reveal four core functions (Visual Generation, Behavioral Logic Generation, Narrative Generation, and Systematic Automation) and their differences in distribution across platforms. It also highlights that AI tools are evolving from being mere “tools” to becoming “Collaborator” and even “Autonomous Agent”, with creator behavior shifting from resource construction to Concept-driven approaches. Combined with an analysis of the user corpus, this study further summarizes three key demands of creators for AI tools: Performance Stability, Creative Control, and Usability Enhancement. The research results not only provide a structured perspective for understanding the platform evolution of AI-UGC but also offer theoretical references and practical insights for the design of Collaborative Mechanism and function integration in future game creation tools.