MiA-Signature: Approximating Global Activation for Long-Context Understanding
Abstract Overview
This paper introduces Mindscape Activation Signature (MiA-Signature), a compact representation that approximates the global memory activation pattern induced by a query over a structured semantic memory space (the "mindscape"). The method models memory access as a two-stage process: broad activation over the memory space followed by construction of a tractable signature via submodular selection of high-level memory units that balances query relevance, coverage, and diversity. The signature can be used as a fixed conditioning signal in static RAG or maintained as an evolving global state in an iterative agent loop. The authors evaluate on four long-context benchmarks (DetectiveQA, NarrativeQA, NovelHopQA, NoCha) spanning multiple-choice QA, open-ended QA, multi-hop QA, and claim verification. Results indicate that MiA-Signature primarily improves evidence selection at retrieval time, while its benefit at answer generation time is more task- and model-dependent.
Novelty
The distinctive contribution is modeling LLM memory access through query-induced global activation over a structured memory space and then approximating that activation with a compact signature built via submodular selection, rather than relying on local retrieval alone. The work also presents a unified signature interface that functions both as a one-shot conditioning signal in static RAG and as an evolving memory state refined iteratively in agent loops.
Results
In static RAG, conditioning retrieval on MiA-Signature improves average Recall@10 by 10.9% and average task performance by 3.8% under the same retriever and generator backbone (MiA-Emb / DS-V3.2). In the iterative agent setting, MiA-Agent improves retrieval recall on every benchmark with retrieval annotations relative to the no-signature agent, with especially clear gains on DetectiveQA-ZH and NovelHopQA. Answer-time ablations show the signature is a more reliable aid for retrieval than for generation, while combining signature and accumulated evidence is particularly helpful on NoCha (71.4 PairAcc vs. 57.1 without any memory state).
Key Points
- MiA-Signature is defined as a compact surrogate of a query-induced global activation pattern over a structured memory space, constructed via submodular selection of high-level memory units for relevance, coverage, and diversity, rather than serving as a simple summary replacement for retrieved evidence.
- The method provides a unified memory interface used both as a one-shot conditioning signal in static RAG and as an evolving global state refined iteratively alongside query rewriting and evidence accumulation in an agent loop.
- Empirically, the approach yields consistent retrieval improvements across four long-context benchmarks in both static RAG and agent settings, while generation-side gains depend on the task and the generator's capacity to exploit global context.
References
- arXiv: https://arxiv.org/abs/2605.06416v1
- Fugu-MT: https://fugumt.com/fugumt/paper_check/2605.06416v1
- Hugging Face Papers: https://huggingface.co/papers/2605.06416