nines

A k9s-shaped terminal shell, specified once and implemented twice — so a tool can be written in whichever language suits its problem and still present the same interface.

Made by Niche-Knack — Smart Tools. Sharp Solutions.

nines/
├── CONTRACT.md    the specification. normative.
├── rust/          ratatui implementation
└── go/            tview/tcell implementation

Install

Go (tview/tcell):

go get github.com/Niche-Knack-Apps/nines/go@latest

import nines "github.com/Niche-Knack-Apps/nines/go"

Rust (ratatui 0.30, crossterm 0.29). The crate is not on crates.io; depend on a release tag:

[dependencies]
nines = { git = "https://github.com/Niche-Knack-Apps/nines", tag = "v0.1.0" }

Both implementations follow the same version. The Go module is tagged go/vX.Y.Z alongside each vX.Y.Z release, because it lives in a subdirectory.

Why

z9s proved the shape. But the shell lived inside one Go binary, so the next tool faced a bad choice: copy it by hand and drift, or pick the language for the shell instead of for the problem.

z9s links Zarf as a Go library. Another tool might share a Rust engine with a desktop app. Neither should have to change language to keep the interface, and a user who learns one should have learned both.

So the contract is the artifact. rust/ and go/ are implementations of it, and where either disagrees with CONTRACT.md, the implementation is wrong.

What it gives you

• A page stack with breadcrumbs, where the root is never popped and a screen holding resources releases them when the user navigates away.
• A header with an info panel, a persistent key legend, and art whose columns are measured rather than hard-coded.
• A command bar that is inserted into the layout, not overlaid.
• One object per action, driving both the hint list and the authority check. An action that is not offered cannot be invoked — the two cannot drift.
• A key-ownership rule that stops the three-layers-fighting-over-Enter failure that prompted this in the first place. See CONTRACT.md §4.1.
• Selection colours that cannot resolve to invisible text, and no meaning carried by colour alone.

What it does not give you

A base class. A screen is three methods — render, name, hints — and opts into anything further. A screen that filters says so; one that does not stays three methods long.

Status

CONTRACT.md is complete.

go/ is the extraction of z9s's UI layer, and z9s runs on it — which is the only real proof it is faithful.

rust/ implements actions, layout, screens and theme against ratatui 0.30.

Art measurement is covered by an identical table in both (go/conformance_test.go, rust/src/layout.rs). Writing it found three divergences on the first run — empty art, trailing newlines, and bytes-versus-cells — none of which z9s's own artwork exercised.

Theme

NINES_THEME=light|dark|neutral picks the palette when terminal detection cannot (it never can under tmux). NO_COLOR is honoured. See CONTRACT.md §8.

Testing

The contract's most important rule is that a screen's apply is callable without a running app, so screens are tested by feeding them a result and asserting on rendered cells — not by driving a live terminal. A shell whose screens can only be tested end-to-end will not be tested.

cd rust && cargo test
cd go   && go test ./...

Releases

Every merge to main runs CI for both implementations. When the merge carries a new version in VERSION (kept equal to rust/Cargo.toml), the release workflow tags vX.Y.Z and go/vX.Y.Z and publishes a GitHub release with notes. A pull request that does not bump VERSION fails its check, so every merge ships.

Support

nines is free and open. Niche-Knack also makes small, sharp, offline-first apps — see them at nk.tools.

Really believe in this project's potential and want to contribute to its development? Buy Me a Coffee.

License

Apache License 2.0. See NOTICE.