ntozier Thank you very much for your reply, but I got no notification about it, I will see if I should have subscribed somehow.
Anyway, my point is that imagine the scenario where an agent wants to create a task and knows in advance that they will need external collaborators, which are users as you described. Currently the agent has to create the task, then add collaborators, and then post an update which the collaborators can receive. What I would like to see is if upon creation of the task, where the agent inputs a title, and adds the description which becomes the first posted message, if the agent could add collaborators that would receive this first message too. One step instead of two for the agent, without having to repeat his first message.