Nix Workstation: Declarative Dev Environment with Nix Flakes & Home Manager

Nov 4, 2025

🧩 Nix Workstation — Cobra’s Declarative Dev Environment

A fully reproducible workstation built with Nix flakes and Home Manager.
Features:

Zsh + Oh-My-Zsh + Powerlevel10k
Autosuggestions & Syntax Highlighting
Neovim with lazy.nvim, Treesitter, and LSPs
Dev tools (Git, Bat, Eza, Fd, Ripgrep, Fzf, Tmux, Lazygit, etc.)
Node 22, Python 3.12, Prettier, Terraform, Docker, AWS CLI
ChatGPT CLI alias (chat) via npx
Direnv + Flakes + Home Manager integration

🚀 Quick Start on a New Machine

Install Nix

sh <(curl -L https://nixos.org/nix/install) --no-daemon
mkdir -p ~/.config/nix
echo "experimental-features = nix-command flakes" >> ~/.config/nix/nix.conf

Clone this repo

git clone https://github.com/YOURUSERNAME/nix-tools.git
cd nix-tools

Activate Home Manager

nix run home-manager/master -- switch --flake .#cobra@linux

Start your new shell
```
exec zsh
```
Powerlevel10k will open its first-time setup wizard.

🧠 Development Shell

Enter your pinned dev environment:

nix develop

Inside you’ll find:

Node 22, npm, and pip
Language servers (TypeScript, Python, Bash, Lua, YAML)
Terraform, kubectl, AWS CLI
Aliases and OMZ prompt
chat alias for ChatGPT CLI (via npx)

To leave the shell:

exit

🔑 OpenAI API Key

Create a private key file (do not commit this):

echo 'export OPENAI_API_KEY="sk-...your-key..."' > ~/.openai_api_key
echo 'export TOKEN="$OPENAI_API_KEY"' >> ~/.openai_api_key
chmod 600 ~/.openai_api_key

Reload your shell:

exec zsh

Test ChatGPT:

chat "Write a Nix expression that prints hello world"

⚙️ Maintenance

Update all inputs (nixpkgs + Home Manager):

nix flake update
git add flake.lock
git commit -m "update nixpkgs + home-manager"

Re-apply configuration:

nix run home-manager/master -- switch --flake .#cobra@linux

🧹 Troubleshooting

Issue	Fix
`powerlevel10k not found`	Run `make link-p10k` or re-apply HM
`direnv conflict`	Remove old profile installs: `nix profile remove direnv nix-direnv`
`terraform unfree error`	`allowUnfree = true` already set in flake
ChatGPT CLI says `TOKEN` missing	Ensure both `OPENAI_API_KEY` and `TOKEN` are exported

💡 Tips

nd alias → opens zsh in dev shell (nix develop -c zsh)
nix fmt → formats your flake
nix flake show → inspect available outputs
home-manager news → view Home Manager changelog

🧰 Stack Summary

Component	Managed by	Notes
Shell	Home Manager	Zsh + OMZ + p10k
Editor	Home Manager	Neovim (lazy.nvim + LSPs)
CLIs	Home Manager	Git, Eza, Bat, Fzf, Ripgrep, etc.
Languages	DevShell	Node 22, Python 3.12
AI	Alias	`chat` → ChatGPT CLI
Config	Flake	One file (`flake.nix`) = entire setup

🔒 Reproducibility

Everything except your API key is declarative.
To recreate this environment anywhere:

curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
echo "experimental-features = nix-command flakes" >> ~/.config/nix/nix.conf
git clone https://github.com/YOURUSERNAME/nix-tools.git
cd nix-tools
nix run home-manager/master -- switch --flake .#cobra@linux
exec zsh

Enjoy your reproducible dev environment ⚙️💀