AI can now remember, update, and forget facts without any external retrieval. A new paradigm for native memory in foundation models has just been published.
Title: Metis: Memory Foundation Model
๐ Overview
Current external memory systems like RAG face three fundamental limitations: decoupling from the model backbone, inability to propagate gradients through discrete memory operations, and added inference latency. Metis integrates memory natively into Transformer blocks โ analogous to how Chain-of-Thought became intrinsic to LLMs โ eliminating external module dependency while enabling learned, end-to-end memory behavior.
๐ Problem and Approach
Two core components are introduced. The Local Memory Block maintains a dense memory network updated across inference steps via exponential moving average, with learned importance scoring and Top-ฯ token selection. The Hyper Memory Block uses static learned parameters to enable memory transformation through the forward pass. Four memory operations โ Remember, Update, Forget, and Reflect โ are executed purely through forward computation without any background gradient updates.
๐ Experimental Results
On the MemOps benchmark (no-context setting), Metis-27B achieves 24.76% average performance:
ยท Baseline Qwen3.5-27B (no context): 1.69%
ยท Test-time training Temp-LoRA-27B: 9.70%
ยท Parametric memory ฮด-Mem: 4.38%
On the Metis internal test set, the model reaches 73.77% average with Reflect (multi-hop reasoning) at 93.44%. It outperforms all no-context baselines across model sizes and tasks.
๐ก Practical Significance
Native memory avoids the retrieval, ranking, and prefilling overhead of RAG through parallelizable computation, keeping inference latency low. Domain adaptation via post-training is supported. Model checkpoints and code are publicly available on GitHub (MemTensor/Metis) and HuggingFace.
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