During August 2025, Bear Zhang developed a backward-compatible optional length check for the masked_select_jagged_1d function in the pytorch/FBGEMM repository. This feature, implemented in C++ and Python with a focus on GPU computing and PyTorch, allows models with varying mask lengths to maintain their original behavior when needed. By introducing the check behind a configuration flag, Bear ensured that default performance and behavior remained unchanged, minimizing migration risk. The work included clear usage guidance to support teams during transitions, reflecting careful change management and a strong understanding of API compatibility while enabling safe experimentation across different model variants.