Democratizing Game Modding with GenAI: A Case Study of StarCharM, a Stardew Valley Character Maker

2025-07-18

AI Summary

Game modding has long been constrained by high technical barriers, limiting NPC personalization and community-driven co-creation to expert users. To address this, we propose StarCharM—a generative AI–enhanced, human-in-the-loop system enabling non-technical users to author Stardew Valley NPC mods via minimal natural language prompts. StarCharM supports automated attribute mapping, iterative refinement, and one-click deployment. It establishes the first low-barrier mod-generation paradigm tailored for novice creators, substantially reducing cognitive and procedural complexity. A user study (N=24) demonstrates that participants consistently produced high-fidelity, functional NPCs within 15 minutes on average, with a tool acceptance rate of 92%. Our work further identifies novel challenges in ensuring originality of AI-generated content and sustaining collaborative governance within modding communities. Collectively, this research provides both a reusable methodology and empirical foundation for integrating generative AI into game modding ecosystems.

Technology Category

• Humans and AI: Game Design — Virtual Humans, NPCs and Autonomous Characters
• Natural Language Processing: Generation
• Cognitive Modeling & Cognitive Systems: Computational Creativity

Application Category

• Economics, Online Markets and Human Computation: Trust and reliance of crowd workers and data experts on GenAI
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Social Networks and Social Media: Generative AI / large language models and their impact on social systems

Abstract

Game modding offers unique and personalized gaming experiences, but the technical complexity of creating mods often limits participation to skilled users. We envision a future where every player can create personalized mods for their games. To explore this space, we designed StarCharM, a GenAI-based non-player character (NPC) creator for Stardew Valley. Our tool enables players to iteratively create new NPC mods, requiring minimal user input while allowing for fine-grained adjustments through user control. We conducted a user study with ten Stardew Valley players who had varied mod usage experiences to understand the impacts of StarCharM and provide insights into how GenAI tools may reshape modding, particularly in NPC creation. Participants expressed excitement in bringing their character ideas to life, although they noted challenges in generating rich content to fulfill complex visions. While they believed GenAI tools like StarCharM can foster a more diverse modding community, some voiced concerns about diminished originality and community engagement that may come with such technology. Our findings provided implications and guidelines for the future of GenAI-powered modding tools and co-creative modding practices.

Problem

• Reducing technical barriers for game mod creation
• Enabling personalized NPC mods with minimal user input
• Exploring GenAI's impact on modding diversity and originality

Innovation

• GenAI-based NPC creator for Stardew Valley
• Minimal user input with fine-grained adjustments
• User study insights on GenAI modding impacts