RAG over Thinking Traces Can Improve Reasoning Tasks

Negar Arabzadeh, Wenjie Ma, Sewon Min, Matei Zaharia


Abstract
Retrieval-augmented generation (RAG) has proven effective for knowledge-intensive tasks, but is widely believed to offer limited benefit for reasoning-intensive problems such as math and code generation. We challenge this assumption by showing that the limitation lies not in RAG itself, but in the choice of corpus. Instead of retrieving documents, we propose retrieving thinking traces, i.e., intermediate thinking trajectories generated during problem solving attempts. We show that thinking traces are already a strong retrieval source, and further introduce , an offline method that transforms them into structured, retrieval-friendly representations, to improve usability. Using these traces as a corpus, a simple retrieve-then-generate pipeline consistently improves reasoning performance across strong models and benchmarks such as AIME 2025–2026, LiveCodeBench, and GPQA-Diamond, outperforming both non-RAG baselines and retrieval over standard web corpora. For instance, on AIME 2025-2026, RAG with traces generated by Gemini-2-thinking achieves relative gains of +56.3%, +8.6%, and +7.6% for Gemini-2.5-Flash, GPT-OSS-120B, and GPT-5, respectively, even though these are more recent models. Overall, our results suggest that thinking traces are an effective retrieval corpus for reasoning tasks, and transforming them into structured, compact, or diagnostic representations unlocks even stronger gains.
Anthology ID:
2026.emnlp-main.1964
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
44722–44743
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1964/
DOI:
Bibkey:
Cite (ACL):
Negar Arabzadeh, Wenjie Ma, Sewon Min, and Matei Zaharia. 2026. RAG over Thinking Traces Can Improve Reasoning Tasks. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 44722–44743, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
RAG over Thinking Traces Can Improve Reasoning Tasks (Arabzadeh et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.1964.pdf