Worked on stabilizing the developer shell environment in the cachix/devenv repository by addressing a critical issue with Zsh startup configuration. Focused on ensuring that environment variables defined in .zshenv are reliably available to .zshrc, the solution involved sourcing .zshenv before .zshrc to improve shell startup consistency. Utilized skills in Zsh configuration, shell scripting, and Rust to implement and validate the fix through targeted testing and review. This work enhanced the reliability of development environments and streamlined onboarding for new contributors by providing consistent environment variable propagation across different setups, reflecting a careful and detail-oriented approach to shell environment management.