Lookup-first: every subcommand, every flag, what it prints. Getting Started shows these commands in context; this is the part you search.
One binary, twelve commands: run, test, check, pack, package, workspace, install, uninstall, init, luau-types, and the two that generate things for your shell, completions and man. Every command that prints a document takes --format. A .jsl path where a command would go, jess script.jsl, runs the script as a program, which is what a shebang line does.
Global Options
The options every command takes: --format, --help, --version; and what every command prints, and how it fails.
jess run
Run a Luau script with the jess API, optionally with packages activated.
jess pack and jess package
Pack a Package Source into a JPK; inspect, resolve, and test packages without running them by accident.
jess workspace
Develop several packages together: find the workspace from any folder in it, run and test its targets, pin what it depends on in jess.lock, and pack it into one file to ship.
jess test
Run Luau test modules built with @jess/test and print one report.
jess check
Type-check scripts in strict mode from the command line, with jess's types and any packages they require. Runs nothing.
jess install and jess uninstall
Put an application on your PATH: a package from its publisher, a packed workspace, or a workspace, embedded in this jess as one executable per command.
init, luau-types, completions, man
The commands that set up your editor and shell.