AI bugs are often questions: Why ignore a sound? Why choose that ally? Why get stuck? A debugger should reconstruct the decision from evidence.
One inspection view
Show identity, goal, task, decisive state, stimuli, path and recent failures. Epic’s debugger combines Behavior Tree, EQS, perception and NavMesh views.
Record transitions
Keep a bounded buffer of observations, scores, transitions and outcomes with timestamps and stable entity IDs. Snapshots miss the moment a condition changes.
Log reasons
Use structured codes such as target_lost, stimulus_age and path_status. Aggregate common failures and rate-limit duplicates.
Replay where possible
Capture random seeds and decision inputs. Mark asynchronous results that cannot reproduce exactly. Pair observability with scenario tests.