In a tower defense, a player can drop one tower that walls off the path and softlocks the wave. The fix isn't to place it and hope pathfinding recovers — it's to validate first: treat the tower as a temporary blocker, ask if a route still exists, revert if it doesn't, and only then commit.
I built a playable Godot 4.7 demo for it: place towers, watch the path reroute, try to seal it and get rejected. The guide also measures the cheap vs expensive way to run that check, with a runnable project.
https://vav-labs.com/blog/tower-defense-path-validation-in-godot/
