During December 2024, Pablo Sanabria focused on improving the stability and path handling of the MITIM-fusion repository. He addressed a critical bug in Python’s pathlib module that caused incorrect folder path assignments during optimization and PORTALS plotting. By converting pathlib.Path objects to strings for replacement operations and then back to Path objects, Pablo restored correct path manipulations and ensured compatibility with downstream plotting tools. This bug fix, leveraging his skills in Python, bug fixing, and file path manipulation, reduced runtime errors and improved the reliability and reproducibility of optimization runs, demonstrating careful attention to root-cause analysis and pipeline robustness.