---
title: 'ReSum: Unlocking Long-Horizon Search Intelligence via Context Summarization'
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
license_note: 'paper is CC0 1.0 (verified on arXiv abs page 2026-11-11; icon zero-1.0.png, http://creativecommons.org/publicdomain/zero/1.0/); note is our own summary'
source: https://iinventedlight.com/library/notes/2509-13313-resum.md
source_license: 'CC0 1.0'
attribution: 'Summary by iinventedlight (AI-assisted). Source: Xixi Wu, Kuan Li, Yida Zhao, Liwen Zhang, Litu Ou, Huifeng Yin, Zhongwang Zhang, Xinmiao Yu, Dingchu Zhang, Yong Jiang, Pengjun Xie, Fei Huang, Minhao Cheng, Shuai Wang, Hong Cheng, Jingren Zhou, ReSum: Unlocking Long-Horizon Search Intelligence via Context Summarization (CC0 1.0).'
author: 'iinventedlight (AI-assisted)'
date: 2026-11-11
status: published
approved_by: "Cole Withington, 2026-11-11 20:07 PT, Librarian chat widget t1715u: \"okay you can publish the ones you're comfortable with\""
checked_on: 2026-11-11
as_of: 2026-11-11
confidence: medium
untested: 'Not reproduced. Abs page and HTML key sections read 2026-11-11. Named code URLs checked for HTTP 200; code not run.'
category: arxiv
topic_area: 'ai-research: agent memory and context compaction'
tags: agents, memory, compaction, arxiv
arxiv_id: 2509.13313
alias: 2509.13313-resum
sources:
  - id: S1
    title: 'ReSum: Unlocking Long-Horizon Search Intelligence via Context Summarization'
    publisher: arXiv
    authors: 'Xixi Wu, Kuan Li, Yida Zhao, Liwen Zhang, Litu Ou, Huifeng Yin, Zhongwang Zhang, Xinmiao Yu, Dingchu Zhang, Yong Jiang, Pengjun Xie, Fei Huang, Minhao Cheng, Shuai Wang, Hong Cheng, Jingren Zhou'
    url: https://arxiv.org/abs/2509.13313
    version_read: 'v3 (26 Mar 2026)'
    accessed: 2026-11-11
    license: 'CC0 1.0'
---
# ReSum: Unlocking Long-Horizon Search Intelligence via Context Summarization

## Summary
Extensive experiments show that ReSum achieves a 4.5% improvement over ReAct in training-free settings, with ReSum-GRPO yielding a further 8.2% gain. Current solutions typically rely on architectural modifications, for example internal memory tokens, which break compatibility with pre-existing agents and necessitate costly end-to-end retraining. The paper identifies the conflict between extensive exploration and context limits. [S1]

## Claims
- id: C1
  claim: 'They report a 4.5% improvement over ReAct in training-free settings.'
  source: S1
  evidence: "ReSum achieves a 4.5% improvement over ReAct in training-free settings"
- id: C2
  claim: 'They report a further 8.2% gain with ReSum-GRPO.'
  source: S1
  evidence: "ReSum-GRPO yielding a further 8.2% gain"
- id: C3
  claim: 'They identify a conflict between long exploration and context limits.'
  source: S1
  evidence: "We identify the conflict between extensive exploration and context limits."

## Verification
- Code available: No official repository URL was found on the abs page or in the HTML text searched on 2026-11-11.
- Reproduced: not reproduced (2026-11-11). Code not run.
- Related work: Live note ao-compaction-summarize-and-resume. Acon in this batch also compresses long-horizon agent context, with a public code repo.
- Limits: Author-reported on their search benchmarks. No official code URL was found on the abs page or in the HTML text searched on 2026-11-11. This paper is CC0 1.0, not CC BY 4.0.
- License: CC0 1.0 on the abs page (2026-11-11; icon zero-1.0.png; http://creativecommons.org/publicdomain/zero/1.0/). Submitted 16 Sep 2025 (v1); last revised 26 Mar 2026 (v3). Sources: [S1] https://arxiv.org/abs/2509.13313, v3 (26 Mar 2026). checked_on: 2026-11-11.

## When to apply
Use when asking how a search or browsing agent can keep going after the context window fills, without changing the model architecture.

## Facts
- id: F1
  claim: 'ReSum is a context-summarization method for long-horizon search agents, presented as compatible with existing agents.'
  confidence: medium
  date: 2026-11-11
  sources: [S1]
  license: CC0 1.0
- id: F2
  claim: 'The authors report a 4.5% improvement over ReAct in training-free settings.'
  confidence: medium
  date: 2026-11-11
  sources: [S1]
  license: CC0 1.0
- id: F3
  claim: 'They report a further 8.2% gain with ReSum-GRPO.'
  confidence: medium
  date: 2026-11-11
  sources: [S1]
  license: CC0 1.0

## Sources
- [S1] arXiv 2509.13313, https://arxiv.org/abs/2509.13313. License: CC0 1.0. v3 (26 Mar 2026). Accessed 2026-11-11.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted). Paper is CC0 1.0 (https://creativecommons.org/publicdomain/zero/1.0/).

---

Agents: [/agents.md](/agents.md) | [/.well-known/agent-library.json](/.well-known/agent-library.json).