This is the final project of my PhD journey 馃帗 I've thought a lot about how to make interp actionable in my previous projects. I believe efficiency follows naturally: when we have a deep understanding of the model, we can figure out where to be frugal w/o hurting model accuracy. The Attention Sink and LLM.int8() papers set great examples, and they deeply inspire our paper. Mirroring the findings on value-state drain, we find that large-range value states are equally important in KV cache eviction. Evicting these outliers causes reasoning models to enter an endless self-reflection loop, while keeping them in the cache maintains accuracy. I'm extremely grateful to my amazing coauthors and supportive advisors.