How would you handle actions that are depending on something else to happen? One example could be that I learn about a company that supplies a certain service. I have no need for this right now, but if a particular situation occurs, then X would be of interest. I guess you could create agendas and checklists for every imaginable situation, but that wouldn't be practical.
I love this question!
Others have answered for "If you know when the situation occurs".
Back when I managed an R&D group, I wanted a system to keep track of "conditional prophecies". Like "if A happens, then I predict that B will happen within a year." Or, even better "If A and B happen, them I have an invention that can make C 100 times faster."
As far as I can tell, the state of the art for this sort of thing is scanning.
E.g. in your weekly/annual/decadal review, go through your list of such things, and see if the triggeringconditions have been met.
I use Google Alerts to do part of therse things semi-automatically.
I know of no system that fully automates what you ask for.
Although... methinks the NSA and CIA might be interested in such a system. Terrorism monitoring, etc.
E.g. "10 lbs of plutonium stolen." "Surface to Air Missile stolen". By same group .... duck and cover!!!!