RESEARCH PROJECT · LONG-TERM MEMORY

DYADMEM A Long-Term Memory Benchmark of How Agents Work with Users

Yifei Tao1,4,*, Xinyu Zhong4,*, Henry Hengyuan Zhao2,*, Fanyi Wang4,*,‡, Tengda Guo4, Wentao Qiu4, Ying Wang3, and Liujian Tang4,†

1Nanyang Technological University 2National University of Singapore 3University of Hong Kong 4Stepfun

*Equal contribution ‡Team lead †Corresponding author

Corresponding author email: alex@stepfun.com

Preprint, 2026

OVERVIEW

Abstract

Long-term agents must remember not only what is true about a user, but also how a particular agent should work with that user as their shared history evolves. Existing benchmarks primarily supervise user facts and preferences or experience reusable across users, leaving this relationship-specific agent memory implicit. Additionally, most prior works measure the model solely with final-answer QA over long interaction histories, making the assessment still incomplete and unreliable. To this end, we introduce DyadMem with the proposed new definition User-conditioned Relational Agent Memory (URAM). DyadMem jointly annotates user-side memory and URAM along the same multi-session trajectories, resulting in 6 memory categories. To summarize, it includes 3,065 episodes, 50,961 sessions, and 61,210 QA instances, with extensive session-level Capture and Update gold annotations, query-level Recall support, and two QA settings: Gold-Memory and Full-Pipeline. Across 16 open-weight and 4 proprietary models, Gold-Memory QA is consistently strong, yet Full-Pipeline QA drops sharply. Such a gap explicitly supports our fine-grained evaluation design. Additionally, several quantitative results further reveal low Capture recall, incomplete Recall, and unsafe-deletion issues arising from even the frontier LLMs. We further conduct a rigorous experiment to validate the effectiveness of our URAM and observe the positive effects for all 20 models. In summary, DyadMem is a dual-domain, full-pipeline memory benchmark with extensive annotation efforts for advancing the domain’s development.

Teaser

Overview of the DyadMem benchmark and memory workflow

DATASET

Data Statistics

Dataset statistics, category distribution, and token composition

METHOD

Data Pipeline

Data pipeline diagram

EVALUATION

Main Results

Unsafe deletion rates across evaluated models
Model ranking under different judge models
Heatmap comparing three evaluation metrics across models

ANALYSIS

Supplementary Analysis

Memory-related results for 20 evaluated models

INTERACTIVE DETAIL

Explore Individual Models

Switch between open-source and proprietary models, then pick one to view its radar chart.

20 MODELS
Radar charts across 25 categories

INTERACTIVE DETAIL

Explore Individual Categories

Pick one of the five scenario groups, then select a category to view its radar chart.

25 CATEGORIES

REFERENCE

Citation

If you use this work, please cite:

@misc{tao2026dyadmem,
  title        = {DyadMem: A Long-Term Memory Benchmark of How Agents Work with Users},
  author       = {Tao, Yifei and Zhong, Xinyu and Zhao, Henry Hengyuan
                  and Wang, Fanyi and Guo, Tengda and Qiu, Wentao
                  and Wang, Ying and Tang, Liujian},
  year         = {2026},
  howpublished = {Preprint}
}