The idea of the "session" is an interesting solution, I'll be looking forward to new developments from you on this.

I don't think it solves the other half of the problem that we've been working on, which is what happens if you were not the one initiating the work, and therefore can't "connect back into a session" since the session was triggered by the agent in the first place.

With the approach based on pub/sub channels, this is possible to do if you know the name of the session (i.e. know the name of the channel).

Of course the hard bit then is; how does the client know there's new information from the agent, or a new session?

Generally we'd recommend having a separate kind of 'notification' or 'control' pub/sub channel that clients always subscribe to to be notified of new 'sessions'. Then they can subscribe to the new session based purely on knowing the session name.