During December 2025, Rainy101112 focused on enhancing the stability and memory safety of CoolPotOS by addressing a critical bug in the string builder component. Working primarily in C, Rainy101112 identified and resolved an overflow vulnerability that could have led to unsafe memory allocation and potential crashes. The fix involved robust memory management techniques to prevent integer overflow, thereby reducing runtime risks and improving the reliability of the core system. Although no new features were released during this period, the targeted bug fix in the plos-clan/CoolPotOS repository demonstrated careful attention to software development best practices and system hardening.