[ISIF 2026] Glass-Box Behaviour Tree Receives a Technology Gold Medal

From 13 to 17 October 2026, HanByul Yu and I presented Glass-Box Behaviour Tree at ISIF 2026. Our project and accompanying paper received a Gold Medal in the Technology category. We participated with support from the Korea Science and Technology Support Group.

The question behind the work#

When a game developer hands a trained agent to a designer, a performance score or gameplay recording offers only a partial account of its behaviour. The designer may need to know which conditions lead to a particular action and whether a simple description of that behaviour is supported by the agent’s actual requests.

Our paper, Glass-Box BT: Behavior-Tree Views for Reviewing Trained Game Agents, addresses that review task. It represents recorded behaviour as a behaviour tree whose conditions and actions can be checked against the original records. The tree is an aid to inspection; it is neither the agent’s internal program nor a replacement for the trained model.

What BranchLens shows#

In BranchLens, a reviewer can open a branch to see a more detailed summary while keeping the original branch visible. The interface places the original summary, the detailed summary, and the model’s recorded action request alongside one another. It also shows cases in which additional detail corrects an error and cases in which it introduces one.

Evaluation and limits#

We examined six fixed PPO and DQN agents across CartPole, MountainCar, and Acrobot. In some cases, the detailed summaries agreed with the agents’ recorded requests more often than the original summaries did. The evaluation also recorded new summary errors, rather than treating every refinement as an improvement.

This is a technical assessment of the summaries. Whether the interface helps people understand an agent or make better decisions remains a question for a separate user study.

At ISIF 2026#

We displayed the research poster and discussed the work with visitors at our booth.

Following the presentation, the project received a Gold Medal in the Technology category. I intend to document the preparation and questions from visitors in a subsequent revision.