Researchers propose APEx, a hierarchical experience utilization framework that organizes interaction history into instance-level trajectory memories and category-level procedural skills to improve deep research agents.

  • The system couples these memories through a closed-loop architecture comprising Executor, Distiller, and Planner modules.
  • These modules are optimized via a three-stage alternating GRPO training paradigm for reward-guided skill distillation.
  • At test time, distilled skills serve as procedural priors for online Planner adaptation using skill-guided test-time reinforcement learning.
  • Experiments on 7 benchmarks show APEx surpasses GPT-5.4 by 14.7 points and the strongest memory-augmented baseline by 3.0 points.

APEx enables ground-truth-free self-improvement with skill-alignment regularization to prevent policy drift, achieving state-of-the-art performance on complex questions.