ALTK-Evolve: Without model weight updates, relying solely on learning-based memory, it tops the τ²-bench customer service benchmark.
IBM Research has introduced the ALTK-Evolve method, which leverages GPT-4.1 to automatically extract structured behavioral guidelines—such as identity verification and refund confirmation—from its own task trajectories. These guidelines are then injected into the ReAct agent system via a purely prompt-engineering approach, significantly improving the accuracy and reliability of customer-service tasks without updating model weights or relying on human annotations. Its retail branch achieved a Pass⁴ score of 67.5%, ranking first on the τ²-bench leaderboard as of October 12, 2026, surpassing all state-of-the-art models and fine-tuned systems.