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Internalizing Multi-Agent Reasoning for Accurate and Efficient LLM-based Recommendation

Paper · 2026 · Yang Wu, Haoze Wang, Qian Li et al.

Summary

LLM-based recommenders struggle with two problems. Collaborative signals (behavioral consensus from many users) are invisible to models that read only item text. Tool-using agents that could fetch such signals are too slow because each reasoning turn adds latency. The authors address both with a two-stage approach. First, they build MARS, a multi-agent teacher that works in a plan–execute–reflect loop. It has a Planner, specialized analysis agents, a Reflector and a Ranking agent. Its Collaborative Signal Translation tool retrieves behavioral neighbours from the user-item graph and turns them into readable textual evidence. Second, MARS trajectories that pass an outcome-based filter are distilled into one Qwen3-8B student, STAR, using SFT followed by GRPO. The student learns to plan, call tools and self-reflect within a single generation. On AgentRecBench data (Amazon, Goodreads, Yelp), STAR beats its own teacher while running much faster. This suggests multi-agent reasoning can be compressed into a deployable single model.

Key points

  • STAR outperforms the MARS teacher by 8.7%–39.5% across scenarios. Its Avg HR (averaged over HR@1/3/5) is 81.9 on Amazon versus 73.0 for MARS, 78.4 versus 66.2 on Goodreads, and 21.5 versus 16.5 on Yelp.
  • On the same Qwen3-8B backbone, trajectory-based SFT lifts Amazon Avg HR from 64.5 (plain SFT) to 78.2, and adding GRPO brings it to 81.9. DeepSeek-V3 with chain-of-thought prompting reaches only 60.6.
  • Inference time falls from 461 s for the teacher to 89 s for STAR, though this is still far from sub-second serving.
  • Strict outcome filtering of teacher trajectories helps. Also accepting trajectories that only hit at rank 3 or 5 lowers results, for example Yelp drops from 20.1 to 17.9.
  • Cross-domain transfer is asymmetric. A model trained on either Amazon or Goodreads performs strongly when applied to the other, and Yelp as a target nearly matches its in-domain score. Evaluation used 20-item candidate sets, not full-corpus ranking.

Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.

 Institutions

 Fields, topics and concepts

📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 18,614 worksInformation Systems · 1,730 worksDecision Sciences · 249 worksManagement Science and Operations Research · 134 works

🧭 Topics 1Research subjects and languages the work is about.Reasoning · 1,685 works

Cite

Cite as Yang Wu, Haoze Wang, Qian Li, Jun Zhang, Huan Yu and Jie Jiang. 2026. Internalizing Multi-Agent Reasoning for Accurate and Efficient LLM-based Recommendation. Findings of the Association for Computational Linguistics: ACL 2026.

The paper itself, not this page. BibTeX from the library's record of the work. DOI 10.18653/v1/2026.findings-acl.2134

@inproceedings{wu2026internalizing,
  title = {{Internalizing Multi-Agent Reasoning for Accurate and Efficient LLM-based Recommendation}},
  author = {Yang Wu, Haoze Wang, Qian Li, Jun Zhang, Huan Yu and Jie Jiang},
  booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
  year = {2026},
  doi = {10.18653/v1/2026.findings-acl.2134},
  url = {https://doi.org/10.18653/v1/2026.findings-acl.2134}
}

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