---
title: 'LongMemEval: Benchmarking Chat Assistants on Long-Term Interactive Memory'
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
license_note: 'paper is CC BY 4.0 (verified on arXiv abs page 2026-11-11; icon by-4.0.png, http://creativecommons.org/licenses/by/4.0/); note is our own summary'
source: https://iinventedlight.com/library/notes/2410-10813-longmemeval.md
source_license: 'CC BY 4.0'
attribution: 'Summary by iinventedlight (AI-assisted). Source: Di Wu, Hongwei Wang, Wenhao Yu, Yuwei Zhang, Kai-Wei Chang, Dong Yu, LongMemEval: Benchmarking Chat Assistants on Long-Term Interactive Memory (CC BY 4.0).'
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: 2410.10813
alias: 2410.10813-longmemeval
sources:
  - id: S1
    title: 'LongMemEval: Benchmarking Chat Assistants on Long-Term Interactive Memory'
    publisher: arXiv
    authors: 'Di Wu, Hongwei Wang, Wenhao Yu, Yuwei Zhang, Kai-Wei Chang, Dong Yu'
    url: https://arxiv.org/abs/2410.10813
    version_read: 'v2 (4 Mar 2025)'
    accessed: 2026-11-11
    license: 'CC BY 4.0'
---
# LongMemEval: Benchmarking Chat Assistants on Long-Term Interactive Memory

## Summary
LongMemEval is a benchmark of 500 questions set in scalable user-assistant chat histories, used to test long-term interactive memory. The authors report that commercial chat assistants and long-context models show a 30% accuracy drop on memorizing information across sustained interactions. They provide two standard history sizes: LongMemEval S at about 115k tokens, and LongMemEval M at 500 sessions (around 1.5 million tokens). [S1]

## Claims
- id: C1
  claim: 'Benchmark and code are stated to be publicly available.'
  source: S1
  evidence: "Our benchmark and code are publicly available at https://github.com/xiaowu0162/LongMemEval"
- id: C2
  claim: 'They report a 30% accuracy drop on memorizing information across sustained interactions.'
  source: S1
  evidence: "showing a 30% accuracy drop on memorizing information across sustained interactions"
- id: C3
  claim: 'LongMemEval S is about 115k tokens per problem.'
  source: S1
  evidence: "LongMemEval S with approximately 115k tokens per problem"

## Verification
- Code available: Paper: https://github.com/xiaowu0162/LongMemEval (HTTP 200 on 2026-11-11). Not run.
- Reproduced: not reproduced (2026-11-11). Code not run.
- Related work: Live note ao-memory-long-term-benchmarks. LongMemEval-V2 in this batch extends the setting toward agent trajectories.
- Limits: Author-reported. History length is freely extensible; the 115k and 1.5 million figures are their standard settings, not a ceiling.
- License: CC BY 4.0 on the abs page (2026-11-11; icon by-4.0.png; http://creativecommons.org/licenses/by/4.0/). Submitted 14 Oct 2024 (v1); last revised 4 Mar 2025 (v2). Comments: ICLR 2025. Sources: [S1] https://arxiv.org/abs/2410.10813, v2 (4 Mar 2025). checked_on: 2026-11-11.

## When to apply
Use when asking how well a chat assistant remembers facts, preferences, or events across a long history, and what benchmark to cite.

## Facts
- id: F1
  claim: 'LongMemEval has 500 curated questions embedded in scalable user-assistant chat histories.'
  confidence: medium
  date: 2026-11-11
  sources: [S1]
  license: CC BY 4.0
- id: F2
  claim: 'The authors report a 30% accuracy drop for commercial assistants and long-context models on memorizing information across sustained interactions.'
  confidence: medium
  date: 2026-11-11
  sources: [S1]
  license: CC BY 4.0
- id: F3
  claim: 'Standard settings are LongMemEval S at about 115k tokens and LongMemEval M at 500 sessions, around 1.5 million tokens.'
  confidence: medium
  date: 2026-11-11
  sources: [S1]
  license: CC BY 4.0

## Sources
- [S1] arXiv 2410.10813, https://arxiv.org/abs/2410.10813. License: CC BY 4.0. v2 (4 Mar 2025). 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 CC BY 4.0.

---

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