arXiv Computation and Language

OptionWorld: A Benchmark for Diagnosing Failures of LLMs as Long-Term Personal Assistants

OptionWorld is a new benchmark that tracks how large language models handle long‑term personal assistant tasks, focusing on information gathering, decision making, actions, and outcomes over simulated daily life scenarios. The study finds that in 35.5% of failed cases the key facts are still present in the model’s last input, and identifies three main failure modes: missing or uncombined information, unused action opportunities, and unnecessary restrictions imposed by the agent. Follow‑up experiments show that providing missing facts, adding action reminders, and correcting erroneous restrictions can improve task success, highlighting gaps in state maintenance, deadline adherence, and assumption handling.

arXiv AI
Oct 26

Knowing When to Stop: The Evidence-Action Gap in Coding Agents

The paper introduces the evidence-action gap, where coding agents persist in tasks even when completion is impossible, despite having sufficient evidence that outside help is needed. To quantify this, the authors present ImpasseBench, a benchmark that injects realistic blockers into repair tasks and marks the step at which evidence becomes sufficient. Across eight models and 19,371 trajectories, they find that many agents still exhaust their budget or make unsafe requests after the evidence threshold, but an escalation tool and external monitor can significantly reduce these failures.

By Tianyu Chen, Xinran Zhao, Vijay Viswanathan, Shoubin Yu, Mingyuan Zhou, Tongshuang Wu
arXiv AI
Oct 5

Sentry: Learning to Recover from LLM Agent Failures at Test Time

Sentry is a failure‑management layer for large language model agents that learns from failures at test time. It retrieves relevant lessons from an external playbook when a failure occurs, verifies recovery without task rewards, and stores new lessons only if recovery succeeds, keeping the playbook out of the agent’s context. Across multiple benchmarks, Sentry outperforms both runtime‑intervention and context‑evolution baselines, and its lessons transfer to unseen tasks.

By Changxiu Ji, Amy Lu, Qizheng Zhang, Kunle Olukotun
arXiv AI
Oct 9

Agent-Controlled Forgetting for Tool-Using Agents: Reversible Context Curation in Practice

Agent-Controlled Forgetting for Tool-Using Agents: Reversible Context Curation in Practice explores a method where an agent selectively replaces detailed tool results with concise notes while archiving the originals for recovery. Using a Python harness, the approach reduces prompt tokens from 912,492 to 231,951 and cuts cumulative input tokens by 50%, yielding significant API cost savings. However, the method increases request count, slightly slows execution, and its effectiveness varies across different workloads.

By Jan-Peter Franke
arXiv AI
Oct 19

Testing the Planning Claims of LLM-Based Agents against Formal Semantics

The paper evaluates the planning abilities of large language model (LLM) agents by comparing their performance against formal semantics defined in hidden PDDL models. Across five domains, four LLMs, six prompting strategies, and three agent architectures, the best setup solved 78% of solvable tasks offline but only 40% online, with limited recognition of unsolvable tasks and no clear benefit from more elaborate prompting. The study concludes that claims of LLM planning competence require validated action traces rather than end‑to‑end success rates.

By Oriol Miro-Lopez-Feliu, Oscar Mir\'o L\'opez-Feliu, Victor Gimenez-Abalos, Javier Vazquez-Salceda, Victor Carballo Araruna, Sergio Alvarez-Napagao