This would be true regardless of whether you engaged in any action at all, however. The passing of time since your last verification of a piece of information is that by which information is lost.

I'm assuming this model is AI-related, so my responses are going to be in line with information modeling with that in mind. If this isn't accurate, let me know.

I would, indeed, suggest time since last verification as the mechanism in your model for information contraction, rather than action; assigning a prior probability that your information will remain accurate does a good job of completing the model. Imagine memorizing a room, closing your eyes, and firing a canon into the room. Contemporaneous to your action, your information is still valid. Shortly thereafter, it ceases to be in a rather dramatic way. Importantly for your model, I think, this is so regardless of whether you fire the canon, or another agent does. If it's a soundproof room, and you close the door with another agent inside, your information about the state of the room can contract quite violently through no action of your own.