The researchers proposed a cross-domain tracker adaptation system that does not require target domain labels, using a visual language model (VLM) as a diagnostic agent. This method performed well in the experiments ranging from MOT17 to MOT20, improving the average HOTA from 0.267 in the source domain configuration to nearly the upper limit of the target domain, at 0.357. Specifically, the average recovery loss performance increased by 67.8%, with a recovery rate of 86.7% in the highest-density sequences. The system directly checks the rendering output through an iterative tuning loop and identifies visual failure patterns, adjusting parameters only when clear failures are detected, thereby overcoming the vulnerability of traditional label-free optimization methods to large domain offsets. The study indicates that the effectiveness of this method depends on whether domain offsets are reflected through detection-level parameter exposure; its effectiveness is limited in scenarios where the source domain configuration is already close to optimal (such as MOT17 to DanceTrack).