Contributing

To iterate on the fork, the Rust library, or the plugin, build by hand instead of using the installer. Four things need to be in place.

Dependency	Why
The koalazub/helix fork	Adds the RawContent API inline rendering depends on. Stock Helix loads nothelix, but images and stacked math fall back to placeholders. See Architecture.
A Rust nightly toolchain	Builds Helix and libnothelix.
Julia	The only supported kernel.
A Kitty-protocol terminal	Inline plots, display math, and tables.

Multiplexers like tmux and Zellij strip the escape sequences Kitty needs, so image-based output stops appearing. Run Helix directly, or use a multiplexer that forwards the Kitty protocol untouched.

1. Build the Helix fork

Build Helix and libnothelix against the same Steel commit so their FFI ABIs match. The fork pins that commit, and libnothelix pins it to match.

git clone https://github.com/koalazub/helix.git
cd helix

# Grammar builds are slow; disable the automatic one and run it after.
HELIX_DISABLE_AUTO_GRAMMAR_BUILD=1 cargo build --release --features steel
./target/release/hx --grammar fetch
./target/release/hx --grammar build

Put hx on your PATH, and point HELIX_RUNTIME at the fork’s runtime directory.

ln -sf "$(pwd)/target/release/hx" ~/.local/bin/hx
export HELIX_RUNTIME="/path/to/helix/runtime"

2. Set STEEL_HOME

Add this to your shell profile so it is set every time Helix launches.

export STEEL_HOME="$HOME/.steel"

3. Install nothelix

git clone https://github.com/koalazub/nothelix.git
cd nothelix
just install

just install builds libnothelix in release mode, copies and codesigns the dynamic library into ~/.steel/native/, and symlinks the plugin sources into ~/.steel/cogs/. Steel’s resolver searches $STEEL_HOME/cogs, so a plain (require "nothelix.scm") loads the plugin. When swiftc is present, the recipe also compiles the optional on-device summary helper. It skips that step silently when swiftc is missing, so summaries simply stay off.

No just? Install it with cargo install just, or read the justfile and run the steps by hand.

The plugin installs under $STEEL_HOME, not the Helix config directory, so config managers like home-manager, stow, and chezmoi never touch it.

On macOS, the dynamic library is re-codesigned after every rebuild. Do not symlink it, because codesign stamps the real file and a rebuild leaves a symlink stale. just install does the copy-then-sign in the right order.

4. Load the plugin

Add this to ~/.config/helix/init.scm, creating the file if needed.

(require "nothelix.scm")

If you previously installed under ~/.config/helix/nothelix*, delete those files. Helix searches the config directory first, so a stale copy shadows the fresh install. just install warns you when it spots one.

Development recipes

Recipe	Description
just install	Build, install, and codesign the library, and link the plugin
just install debug	The same, with the debug profile
just build	Build the library without installing
just build-wasm	Build the Playground WebAssembly bundle into docs/assets/eng/wasm
just test	Run the libnothelix tests with nextest
just check	The pre-commit gate. Runs clippy, nextest, and a real plugin-load check in a live hx
just setup-lsp	Ensure the default Julia env has the kernel’s JSON3 dependency (see Language server)
just uninstall	Remove the installed library and plugin links

Run just install and restart Helix after any Rust change. Helix caches the plugin modules and the loaded library, so a full restart picks up edits where a config reload does not.

Contributors can drop into a pinned dev shell with the fork toolchain, Julia, and tree-sitter through nix develop. The flake pins its toolchain inputs, so a nix flake update will not silently move the build.