Steer2Edit: From Activation Steering to Component-Level Editing

Steering methods influence Large Language Model behavior by identifying semantic directions in hidden representations, and are typically realized through inference-time activation interventions that apply a fixed, global modification to the model's internal states. While effective, such interventions often induce unfavorable attribute--utility trade-offs under strong control, as they ignore the fact that many behaviors are governed by a small and heterogeneous subset of model components. To alleviate the trade-offs, we propose Steer2Edit, a theoretically grounded, training-free framework that transforms steering vectors from inference-time control signals into diagnostic signals for component-level rank-1 weight editing. Instead of uniformly injecting a steering direction during generation, Steer2Edit selectively redistributes behavioral influence across individual attention heads and MLP neurons, yielding interpretable edits that preserve the standard forward pass and remain compatible with optimized parallel inference. Across multiple tasks including safety alignment, truthfulness promotion, and reasoning efficiency, Steer2Edit consistently achieves a superior attribute--utility trade-offs: at matched downstream performance, it outperforms the strongest steering baseline by 17.2% in safety, 9.8% in truthfulness, and 12.2% in reasoning length reduction. Overall, Steer2Edit provides a principled bridge between representation steering and weight editing by translating steering signals into interpretable, training-free parameter updates.