Hi rurounijones, you're right in pointing out the important difference between imperative vs. descriptive form. In our application we intend to accommodate both - hence the inline syntax within the free text.
So you could write in a very succinct way "@John please !phone client" like when you drop over a quick note on Post-It to your colleague-friend sitting next table. But you could also send as a more polite request, something like "@john, can you be so kind to !phone the client". Or what you just wrote "@John said he would !phone client and discuss requirements". These all refer to the same action: John should phone the client.
P.S. In the video we were of course limited by keeping the text as short as possible so it remains legible.