Worked on the IAS-Astrophysics/athenak repository to enhance the reliability of binary file operations by addressing a critical bug in the binary serialization process. Focused on C++ and file I/O, the effort centered on correcting the return value check in the Write_any_type_at* function, ensuring that the number of bytes written matched the intended data size rather than a fixed value. This change prevented potential binary corruption and improved data integrity. The fix was applied across relevant source files, accompanied by code linting to support maintainability. No new features were introduced, emphasizing a commitment to correctness and long-term code stability.