Worked on the flox/flox repository to enhance build reproducibility by implementing deterministic coreutils usage within the Nix build environment. Addressed nondeterminism in file copying by enforcing the use of coreutils/cp for manifest and environment files, invoking these commands with absolute paths tied to the Nix coreutils package. This approach ensured that builds remained consistent across local development, CI, and production deployments. Leveraging skills in Nix, CI/CD, and build environment management, the work improved artifact auditing, strengthened hermetic builds, and increased caching reliability. The changes reduced environment drift and simplified the process of maintaining reproducible builds across multiple platforms.