Chromebooks with stylus will soon be able to launch the Assistant using the stylus, this is a known fact. We also know that Chromebook stylus will soon be known as Assistant Pen. Looks like the team is almost ready with this new feature. William Greene of the Chromebook community has posted a recent Assistant sighting from the Canary channel:
The Stylus menu shows up when you remove the stylus from its port. It presents the regular stylus functions like taking screenshots and creating notes etc. Soon, you will be able to launch Google Assistant using the stylus, or stylus menu.
One more step close to Assistant launch on Chrome OS!