Beto Trevisan contributed targeted improvements to user experience and error handling across the Livebook and Gleam repositories. In Livebook, Beto refined the session closure interface so that danger hints now display only when a session lacks an associated file, reducing unnecessary warnings and clarifying user actions. For Gleam, Beto enhanced compiler error messages related to variant-custom types, providing developers with actionable guidance when field definitions are inconsistent. These changes were implemented using Elixir and Rust, demonstrating skills in compiler development, language design, and web development. The work focused on practical, user-centric solutions and maintained consistency across both codebases.