kosa8 documentation

kosa8 gives an AI assistant its own sealed computer, and gives you a way to save that computer mid-task, copy it, and put it back when something goes wrong.

These pages cover all of it: short walkthroughs you can follow end to end on your own machine, and a reference page for every one of the 134 commands, generated from the binary itself so it cannot drift from what your copy actually does.

New here?

Read Install, then Your first sandbox. Fifteen minutes and you will have run something in an isolated machine, saved it, broken it on purpose, and put it back.

Start with a walkthrough

Install One line, or the Mac app. Both take about a minute. Your first sandbox Make a sealed machine and run something inside it. Save and undo Checkpoint before something risky, rewind after it goes wrong. Try several ideas at once Fork a machine per idea and let kosa8 report which worked. Run an AI assistant Claude Code, Codex, Copilot and others, each sealed off. The Mac app A window onto everything running. Company rules Signed policy that a laptop cannot edit its way around. Local models Run AI on your own machine, no tokens, nothing sent out.

What makes kosa8 different

Most container tools can save your files. kosa8 saves the whole running machine — the programs that are open and what they were part-way through doing. Bringing one back does not restart anything: a server that was running is still running, from the moment you saved it.

That is what makes copying useful. A copy is not a fresh machine you have to set up again. It is the finished one, already warm, ready to try something.

# save it, break it, put it back
$ kosa8 checkpoint web --label "before migration"
checkpoint web-ckpt-1 (before migration) saved in 2281ms

$ kosa8 rewind web
web is back at web-ckpt-1 (1065ms)
  processes resumed from 2m ago

Find a command

Press / anywhere on these pages to search, or browse the full command reference. Every page lists the flags, their defaults and what the command prints.

Before you start

The part that actually runs containers needs Apple's Virtualization framework, so it works on Apple Silicon Macs only. On Windows and Linux you get the command-line tool, pointed at a Mac that does the work. Shared folders run at about a third of native speed — a real cost of the isolation, and one we would rather you read here than discover later.