Memento 3 with Frozen LLM Achieves Perfect Score on ARC-AGI-3; External Rulebook Challenges Weight Training
Memento 3, released on October 8, 2026, solved all 25 public ARC-AGI-3 tasks with a frozen LLM and an external natural-language rulebook, reaching a mean relative human action efficiency of 100.0 while using only 44% of the human baseline action steps. The result positions external memory and code-as-model approaches as a possible challenge to weight-training-centric scaling.