In autonomous navigation there's a concept taken from sailing called "dead reckoning", where you just use an internal model of the robots dynamics to make controller commands. It works for short distances, but without feedback from sensors, the path the robot takes quickly diverges from the intended one as errors accumulate quadratically over the distance travelled. If the robot travels far enough without any external feedback, the localizer can "diverge", meaning its belief about where the robot is becomes wildly off from where the robot actually exists, making safe control virtually impossible.

Now, if you've got a really good model you can get much further with dead reckoning compared to a worse model. But a model is not reality so no matter how good it is, so without feedback eventually you still run into this problem no matter what.

I imagine that's a lot like what goes on in these agentic loops.