Worked on the huggingface/open-r1 repository to deliver a targeted bug fix for the length-based rewards component, focusing on improving API consistency and reliability in Python. Addressed a correctness issue by renaming the solutions parameter to solution, updating the associated docstring, and refactoring the loop to use the singular parameter, ensuring accurate reward calculations for downstream model training. This change aligned the codebase with intended API semantics and reduced the risk of miscalculation in production environments. The work demonstrated attention to detail in bug fixing and code refactoring, resulting in clearer documentation and more reliable reward-based training integrations.