Aging with GRACE: Lifelong Model Editing with Discrete Key-Value Adaptors

Deployed models decay over time due to shifting inputs, changing user needs, or emergent knowledge gaps. When harmful behaviors are identified, targeted edits are required. However, current model editors, which adjust specific behaviors of pre-trained models, degrade model performance over multiple edits. We propose GRACE, a Lifelong Model Editing method, which implements spot-fixes on streaming errors of a deployed model, ensuring minimal impact on unrelated inputs. GRACE writes new mappings into a pre-trained model’s latent space, creating a discrete, local codebook of edits without altering model weights. This is the first method enabling thousands of sequential edits using only streaming errors. Our experiments on T5, BERT, and GPT models show GRACE’s state-of-the-art performance in making and retaining edits, while generalizing to unseen inputs.