Worked on enhancing gem source management in the rubygems/rubygems and ruby/ruby repositories by implementing preservation of per-source cooldown settings during Gemfile and lockfile merges. Addressed a regression where cooldowns defined in the Gemfile were not consistently respected, ensuring deterministic behavior for gem source updates and installations. Utilized Ruby and Ruby on Rails for backend development, focusing on gem management and robust testing practices. Added comprehensive end-to-end tests to validate cooldown preservation, which improved reliability and predictability of dependency management. The work contributed to more stable CI processes and aligned with goals of reducing build variability and supporting maintainable codebases.