AlphaToken: Decoupling Adaptation and Stability for Path-Aware Response Token Valuation in LLM Post-Training
Researchers introduce AlphaToken, a framework that improves large language model post-training by valuating individual response tokens based on their contribution to both task adaptation and preservation of pre-trained knowledge. The method uses gradient-based signals and a Fisher-drift proxy to identify high-value tokens, enabling more efficient fine-tuning and preference optimization while reducing catastrophic forgetting.