Liquid AI Open-Sources Antidoom: A Final Token Preference Optimization (FTPO) Method that Reduces Doom Loops in Reasoning Models

Liquid AI released Antidoom, an open-source method that targets doom loops in reasoning models. A doom loop repeats a span until the context window is exhausted. Antidoom finds the token that starts the loop and retrains only that position using Final Token Preference Optimization (FTPO). On LFM2.

5-2. 6B, doom-loop rates fell from 10. 2% to 1. 4%; on Qwen3. 5-4B, from 22. 9% to 1%. Generation, detection, and the FTPO trainer are open source.