Worked on reliability and safety improvements in core Elixir projects, focusing on backend development and error handling. In the elixir-lang/elixir repository, addressed build tool robustness by ensuring that the mix do command aborts execution on task failure, preventing downstream tasks from running and providing clearer failure signals for developers. Later, contributed to elixir-ecto/ecto by hardening Ecto’s Repo functions, introducing runtime checks to prevent unscoped deletions when query-like keyword options are misused. These changes improved developer safety and clarified error messaging. Demonstrated expertise in Elixir, Ecto, and build tools, with a focus on precise, low-surface-area enhancements to core workflows.