I found that there has been a lot of changes in HA <-> Google Assistant, so I started over on the routines in Assistant.
During this I moved the routines to the new ‘home’ routines, instead of them being for me personally, making it much more usable.
I found though that a ‘scene’ from HA is not available for anybody but me, so I changed the routine so it instead invokes an input_boolean, that just starts the script.
I then made a small node-red flow that detects the change, does the cast, and then turns off the input_boolean again.
If I invoke it, I can see it running the flow, and I can see the input_boolean change, and then reset.
First time I run it, it shows the graph on the Google Hub, but not the second time?
I seem to have to turn off the entire hub for it to show up again?