The Open Safeguard Hackathon, held in San Francisco on December 8, 2025, brought together safety experts, researchers, and policy leaders to collaboratively address AI-driven online safety challenges. Organized by ROOST, Hugging Face, and OpenAI, the event highlighted the importance of open collaboration in developing community-governed safety tools. Participants, including tech companies, nonprofits, and academia, engaged in projects across three tracks: Policy Development, Model Testing, and Real-World Applications, utilizing open safety models like OpenAI's gpt-oss-safeguard. The hackathon fostered creativity and transparency, showing the need for adaptable safety models that cater to specific organizational needs. It also emphasized the value of a connected community in exploring new use cases for AI safety tools. The event marked the beginning of ongoing efforts by the ROOST Model Community to host more hackathons globally, aiming to empower organizations with accessible safety solutions.