Long-running agents: the long and short of it -- Daniel Khashabi

Long-running agents: the long and short of it -- Daniel Khashabi

🎙 Daniel Khashabi 👥 4K 📅 September 14, 2026 ⏱ 30 min 👁 7 📄 original study 🧭 2026-09-14
Available in: English (current) Français

Keywords

long-running agentscontext scalinginformation abundance paradoxself-compactionrubric prompts

Summary

The talk by Daniel Khashabi addresses the challenge of building long-running AI agents that maintain continuity across tasks and time. He identifies a gap in current agents: they operate in isolated sessions, lacking memory reuse. He proposes two bets: 1) scaling the context window indefinitely, and 2) managing a bounded context via adaptive compaction. For the first, he presents experimental evidence that increasing pretraining context length can hurt performance due to an ‘information abundance paradox’ — models internalize less when too much information is readily available in context. This suggests that naive scaling may not work. For the second, he introduces ‘self-compaction’, a method where a rubric prompt autonomously decides when to trigger context summarization, avoiding the pitfalls of fixed-interval compaction. Experiments show improved accuracy with comparable cost. He concludes that future agents should focus on context management rather than unbounded scaling.

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Critical Evaluation

Value of the Information & Strength of the Argument

The talk provides valuable insights into the limitations of context scaling, backed by a controlled experiment that isolates the effect of training context length. The ‘information abundance paradox’ is a novel and thought-provoking finding, with clear implications for model training. The argumentation is logical, moving from observed trends to a hypothesis, then to experimental validation. The second part, self-compaction, offers a practical and simple solution that outperforms baselines, with a detailed explanation of its design and computational efficiency. The speaker acknowledges the simplicity of the approach and highlights potential for improvement. The overall argument is convincing and well-supported by preliminary results, though the sample of benchmarks is limited.

Scientific Rigor, Source Quality, Title Accuracy

The scientific rigor is high: the speaker describes a controlled experiment with fixed data and compute, varying only the training context window. He also compares multiple baselines and analyzes the effect of problem difficulty. However, no external sources are cited explicitly; the talk relies on the speaker’s own research and mentions benchmarks like MIMO and Browse without providing references. The title is perfectly aligned with the content, and the talk stays on topic throughout. The absence of citations does not undermine the internal validity of the presented work, but external verification of claims would strengthen confidence.

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Title / Content Match

The title accurately reflects the content: it discusses long-running agents, focusing on two main strategies — scaling context ('long') and managing bounded context via compaction ('short'). The subtitle 'the long and short of it' is a fitting play on words.

Quality & Reliability

8/10

The talk is presented by a researcher at JHU, based on original experiments conducted by his team. The methodology is transparent and includes controlled experiments on context scaling and a new compaction algorithm. However, the results are not yet peer-reviewed in this format, and some claims rely on specific benchmarks that may not be representative. Overall, the scientific rigor is high but with expected limitations of a conference-style presentation.

Key Moments

Cited Sources

  • Project Gutenberg — Source of long documents used in the context scaling experiment.
  • Browse benchmark — Mentioned as a benchmark for evaluating long-running agents.
  • MIMO v2 — Benchmark used for evaluating self-compaction performance.

Contribution & Novelties

The talk contributes two main novelties: (1) empirical evidence for the ‘information abundance paradox’ in LLM context scaling, showing that longer pretraining contexts can reduce internalization and hurt downstream performance; (2) a lightweight, adaptive self-compaction algorithm that uses a rubric prompt to let the model decide when to compress its context, improving accuracy without significant cost overhead. The approach requires no training and leverages metacognitive prompting.

Pour aller plus loin :

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Radar Profile

The radar profile shows high scores in information quantity and technical depth, with slightly lower marks in qualite_information and fiabilite_globale. This reflects a presentation rich in experimental detail and original findings, but with reliance on unpublished results and limited external sourcing.

Reliability 8/10