Membox: Weaving Topic Continuity into Long‑Range Memory for LLM Agents

Remembering an interaction requires preserving how its parts belong together. Cognitive research describes how continuous experience is organized into structured events: event segmentation theory models the maintenance of an ongoing event representation and its updating at boundaries, connecting this organization to subsequent memory encoding zacks2007event. Discourse theory similarly explains coherent interpretation through the interaction of linguistic structure, communicative intentions, and attention grosz1986attention. In dialogue, a question, a reply, and a qualification may therefore belong to one unfolding exchange despite differences in their surface semantics. These perspectives motivate a construction question for agent memory: what should be preserved together as a retrievable unit? Local organization is only part of this problem. The event-indexing model of narrative comprehension describes connections among events along time, space, protagonists, causality, and intentionality zwaan1995construction. Drawing on these accounts, we formulate two complementary requirements for dialogue memory: preserve supporting exchanges within local units, and provide access between related experiences across unit boundaries. The resulting design must balance local coherence with cross-episode continuity as dialogue accumulates. Existing memory systems use enrichment, updates, indexing, and association to maintain useful representations and connections zhong2024memorybank,xu2025mem,chhikara2025mem0. These mechanisms can encode context, but retrieving a relevant record does not necessarily expose its surrounding exchange. Figure fig:existing illustrates the consequence: a question about continuing to run may require a training plan, recurring knee pain, and advice to reduce intensity. Retrieving the training and pain records can still omit the advice, whose importance comes from its role in the exchange rather than a strong direct match to the query. The facts may remain stored, while their joint availability depends on additional retrieval or linking.