macOS
macOS 13 Ventura or later. Signed and notarized.
Free for macOS and Windows. It runs on your own machine and keeps itself up to date.

Pick the file that matches your computer. Every build is the same app and the same version.
It is in your Downloads folder.
Then eject the disk image.
Any OpenAI-compatible or Anthropic-style endpoint works. Your key stays on this computer.
It installs for your user account and needs no administrator rights.
Choose More info, then Run anyway.
Any OpenAI-compatible or Anthropic-style endpoint works. Your key stays on this computer.
From version 0.8.4 on, cowork finds new versions on its own, shows you what changed, and installs them when you say so or when you quit.
Version 0.8.3 and earlier cannot find updates. Install the current version once from this page, and you are set.