Nix flake organization

Keep flake/ as the public output layer and src/ as the implementation layer. The flake tree names, routes, and re-exports outputs; feature behavior, module bodies, package derivations, app scripts, and helper logic live under src/<name>/....

Apply codebase-design within those boundaries: keep each feature's implementation together and extract only to hide complexity or enable useful reuse. Nix output adapters are meaningful public entrypoints; additional internal forwarding files need their own purpose. Preserve Nix's roles rather than imposing TypeScript models/ and services/ directories.

When to use

• A user asks to reorganize or refactor a Nix flake layout.
• Flake outputs are crowded into flake.nix or mixed with implementation code.
• NixOS, nix-darwin, Home Manager, or flake-parts modules contain business logic directly in output wiring files.
• A repo needs a clear split between public flake API and implementation internals.

When NOT to use