Open source software (OSS) underpins modern software infrastructure, yet many projects struggle with long-term sustainability. We introduce OSSPREY, an AI-powered platform that can predict the sustainability of any GitHub-hosted project. OSSPREY collects longitudinal socio-technical data, such as: commits, issues, and contributor interactions, and uses a transformer-based model to generate month-by-month sustainability forecasts. When project downturns are detected, it recommends evidence-based interventions drawn from published software engineering studies. OSSPREY integrates scraping, forecasting, and actionable guidance into an interactive dashboard, enabling maintainers to monitor project health, anticipate decline, and respond with targeted strategies. By connecting real-time project data with research-backed insights, OSSPREY offers a practical tool for sustaining OSS projects at scale.