Worked on backend and developer tooling across elixir-lang/expert and mason-org/mason-registry, focusing on correctness and developer experience. In elixir-lang/expert, addressed client-driven character offset handling by implementing precise clamping and UTF-8 aware document extraction, refactoring the extraction logic to robustly support both ASCII and UTF-8 encodings. Added automated tests to ensure reliable application of batched incremental changes, improving maintainability. For mason-org/mason-registry, delivered Neovim LSP integration for the oxfmt package, enabling seamless LSP-based workflows and reducing manual configuration for contributors. Utilized Elixir, YAML, and skills in API development, LSP integration, and testing to enhance reliability and usability.