robo-nix

Appearance

CLI UX ​

Human output should follow the original robo CLI shape: one clear status surface, sparse color, lowercase headings, and pasteable captured logs.

Sections ​

Use lowercase section headings without trailing colons:

text
generated
  ✓ wrote    ./flake.nix
  ✓ wrote    ./robo.nix

inferred
  ✓ native-build   pyproject.toml dependency `evdev`
    evdev builds native extensions for Linux input devices.
  ✓ linux-headers  pyproject.toml dependency `evdev`
    evdev native extensions include Linux input headers.

Color only the scanning anchors in terminals:

  • section headings and active status labels: cyan and bold
  • success marker ✓: green and bold
  • attention marker !: yellow and bold
  • field or action words such as wrote: dim
  • quoted or backticked commands: green

Captured output must stay plain text with no escape codes.

Status ​

Use direct status text for active work. Add a phase only when it disambiguates otherwise similar concurrent work:

text
evaluating runtime shell
launching zsh

In terminals, long silent work uses the original nested progress tree. The parent line names the command, the active child names the current phase, and short dim details may appear under the active phase when Nix emits useful progress:

text
⠋ robo shell
  └ ⠋ evaluating runtime shell          2 packages    812ms
    copying '/workspace/' to the store

Leave a completed tree behind when the bounded setup phase succeeds:

text
✓ robo ready                                            42ms
  └ ✓ evaluating runtime shell          cached         13ms

Do not animate while a child process is producing useful output. For robo shell, capture the runtime shell environment with the tree first, then launch the interactive shell directly without an active tree.

Disable animated output when stderr is not a terminal, when NO_COLOR is set, when ROBO_NIX_DEBUG=1 is set, or when ROBO_NIX_NO_SPINNER=1 is set.

Shell Launch ​

robo shell launches the user's default interactive shell. Selection order:

  • ROBO_NIX_SHELL
  • $SHELL, unless it points at generic Nix Bash or plain sh
  • the login shell from /etc/passwd
  • the parent interactive shell
  • zsh, bash, fish, then sh from PATH

Interactive shells show the original [robo] prompt prefix by default. The prefix is injected through temporary startup files under .robo-nix/shell-startup/; it does not edit user dotfiles. The prefix is added to the user's existing prompt. robo does not invent a project-name prompt.

The same startup files run a prompt-time freshness check. If flake.nix, flake.lock, .python-version, pyproject.toml, uv.lock, robo.nix, or the default .venv/bin/python changes while the shell is active, robo reports the changed inputs, re-evaluates the runtime shell, and exports the refreshed environment into the current shell. This refresh does not rewrite robo.nix and does not run uv sync.

Once the Nix runtime environment has been captured for a runtime input key, subsequent robo shell and robo run attempts may show the evaluation step as cached and skip re-running nix develop. Cache reuse must validate referenced Nix store paths first.

Wording ​

Describe ownership boundaries directly:

  • uv owns Python dependency sync.
  • Nix owns native/runtime libraries.
  • robo.nix is user-managed after first bootstrap.
  • Host CUDA drivers are host-owned; robo may bridge a detected libcuda.so.1 provider when the project needs it.