diff --git a/src/skills/style/nix/rules/flake.md b/src/skills/style/nix/rules/flake.md
index 9890684..6535c66 100644
--- a/src/skills/style/nix/rules/flake.md
+++ b/src/skills/style/nix/rules/flake.md
@@ -5,8 +5,11 @@
 ### Rule
 
 Add flake inputs in `flake.nix`.
-Put root flake output implementation in `src/flake/default.nix`.
-Put domain-specific output implementation near the domain it configures.
+Put root flake output composition in `src/flake/default.nix`.
+Keep `src/flake` focused on composing public outputs from implementation files it imports.
+Put project-specific package implementation in that project's source tree, for example
+`src/xatu/package.nix`.
+Put NixOS and dotfiles implementation in `src/dotfiles`.
 Use `flake.nix` to pass inputs into the root flake implementation.
 
 ### Rationale