ALTK-Evolve: How learned memory tops the τ²-bench leaderboard on customer service tasks without a frontier model

ALTK-Evolve, utilizing GPT-4.1, has demonstrated superior performance on the τ2-bench customer service agent benchmark without requiring model weight updates. It achieved an 82.5% lossless score in the Retail category, a 4.4% improvement over the baseline, and a 65.0% lossless score in the Airline category, a 7.5% improvement. This system learns and applies a playbook, outperforming retail entries and showing significant gains with 146 guidelines compared to a baseline of 0.

This report details how ALTK-Evolve achieved a 4.4% higher lossless score on the τ²-bench retail customer service benchmark using learned memory, unlike other models that require weight updates.