Install

jess is one binary called jess. Get it onto your PATH and you're done; completions and man pages are optional extras it can generate for itself.

From a release archive§

The GitHub releases page has one zip per platform:

There's no 32-bit build and no Android one; use cargo install there. Each zip holds, with no folder around them:

• jess (jess.exe on Windows), the whole tool
• jess-<platform>.bundle, the binary's Sigstore signature (below)
• jess-README.md
• LICENSE-MIT and LICENSE-APACHE, the two license texts (pick either)

Everything else lives on this site. The Luau types aren't in the zip, on purpose: jess init or jess luau-types writes them for the jess you actually have (see Editor Setup).

The binary is signed with cosign from the GitHub Actions run that built it. To check that the jess you unpacked is the one CI built:

cosign verify-blob jess --bundle jess-Linux-X64.bundle \
  --certificate-identity-regexp '^https://github.com/DreamWeave-MP/' \
  --certificate-oidc-issuer https://token.actions.githubusercontent.com

Unpack it and put jess somewhere on your PATH.

Linux and macOS. ~/.local/bin is the usual spot:

mkdir -p ~/.local/bin
cp jess ~/.local/bin/
chmod +x ~/.local/bin/jess

If your shell can't find it afterwards, add ~/.local/bin to your PATH:

On macOS, a binary you downloaded may be quarantined, and Gatekeeper refuses to run it; xattr -d com.apple.quarantine ~/.local/bin/jess lets it run.

Windows. Make a folder such as C:\Tools\jess and put jess.exe in it. Then add that folder to your user Path, either through Start → Edit environment variables for your account → Path → Edit → New, or from PowerShell:

$dir = "C:\Tools\jess"
$path = [Environment]::GetEnvironmentVariable("Path", "User")
[Environment]::SetEnvironmentVariable("Path", "$path;$dir", "User")

Open a new terminal afterwards; old ones keep the old Path.

From crates.io§

With a Rust toolchain (1.92 or newer):

cargo install jess

That builds the jess binary into ~/.cargo/bin, which rustup already put on your PATH, and takes a few minutes, since it compiles Luau from source. Run exactly as above it will stop with a message from L3i's build script, the runtime underneath jess, which refuses to build without the toolchain it is measured on rather than quietly hand you a slower binary. You have two choices.

The verified build, the one the release archives are: clang and lld on the same LLVM major as your rustc (rustc -vV and clang --version show the majors; on Debian and Ubuntu that's clang-N lld-N for rustc's LLVM N, on Fedora clang lld, on macOS LLVM's own release rather than Apple's clang), with the flags L3i checks for:

CC=clang CXX=clang++ RUSTFLAGS='-Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld' cargo install jess

The unverified build, with whatever C++ compiler your platform has and no cross-language LTO:

L3I_UNVERIFIED_TOOLCHAIN=1 cargo install jess

It works, and it says what it is: jess --version prints (unverified toolchain, no cross-language LTO: not for measuring), and jess.bench refuses to post a number from it. For a binary to measure with, take the archive. Upgrade later by running the same command again.

From a git checkout§

git clone https://github.com/DreamWeave-MP/jess
cd jess
cargo build --release

The binary lands at target/release/jess. cargo run -- <command> runs a debug build without installing anything. Building and Testing has the rest.

Check it works§

jess --version

jess 0.2.2

Every subcommand takes --version too, and jess help (or jess <command> --help) lists what's there.

Shell completions§

jess completions <shell> prints a completion script for bash, elvish, fish, powershell, or zsh. Save it where your shell looks, creating the folder if it's missing:

Regenerate them after upgrading jess, so new commands and flags complete.

Man pages§

jess man prints jess(1) to stdout:

jess man > jess.1
man ./jess.1

jess man --output <folder> writes jess.1 plus a page for every command (jess-package-inspect.1, jess-workspace-sync.1, and so on) and lists what it wrote. man looks for pages in a man1 folder under each entry of its search path, so write them straight into one:

jess man --output ~/.local/share/man/man1
man jess-package-inspect

On most Linux systems ~/.local/share/man is already searched. If man jess says there's no entry, add export MANPATH="$HOME/.local/share/man:" to your shell's rc file (the trailing : keeps the system pages).

Editor types for scripters§

If you're going to write Luau, jess init my-scripts sets up a folder with the types for the jess you have installed, an example script, and your editor's luau-lsp settings. Editor Setup covers VS Code, Neovim, Zed, and Helix.

Upgrading§

Replace the binary the same way you installed it: unpack the new zip over the old jess, or rerun cargo install jess. Then refresh what was generated from the old one:

• Script types: jess init <folder> in each script folder rewrites types/ and leaves your files alone.
• Completions and man pages: rerun the commands above, so new commands and flags show up.

Read the release notes on the releases page first. Until 1.0, a minor version can rename a flag.

Uninstalling§

jess keeps no state of its own: no config folder, no cache, no registry entries. What it writes, it writes where you pointed it. Delete what you put on disk:

• the binary (~/.local/bin/jess, C:\Tools\jess\jess.exe, or cargo uninstall jess), and the Path entry if you added one;
• the completion file and man pages, if you generated them;
• the types/ folders jess init wrote, if you don't want them, and a workspace's .jess/packages, which jess workspace sync fills and recreates on demand;
• any .bak files jess made next to files it replaced with --force, once you're sure you don't want them.

Next§

Write your first script. Only jess init writes anything, and only in the folder you name.