The downstream flake at ~/.nomarchy is a live working tree by design — nomarchy-theme-sync rewrites theme-state.json on every switch — so Nix's dirty-tree warning fired on every sys-update/home-update and was just noise. Default nix.settings.warn-dirty to false (mkDefault, overridable). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>