Setting up a clean environment is the easy part. Keeping it clean is the real work — and most of that work is subtraction.

The same four-layer architecture made concrete for Node, Java, Swift, Rust, Go, and Ruby — recommended stack, pitfalls, lockfiles, and gitignore for each.

Don't put every language under mise. One test decides who owns runtime versions: does the language ship a strong, official tool of its own?

uv quietly prefers its own managed Python, which conflicts with mise owning runtime versions. One setting — python-preference = only-system — makes them agree.

Not every layer deserves strict declarative management. The app layer is fine with eventual consistency, as long as the drift stays visible.

Move zsh config out of the home directory with ZDOTDIR, split it into modules, and manage it declaratively with chezmoi so drift becomes visible.

Clean means single-source-of-truth layering, not installing the fewest tools.