arXiv AI

Model Capacity Frontier: A Development Framework for LLM-Supported Social Simulation

The paper introduces the Model Capacity Frontier (MCF), a framework that maps the empirical performance achievable by a given architecture across its possible configurations, particularly for large language model (LLM)-supported agent-based models (ABMs). Using a crowd simulation of university commencement events with about 12,000 agents, the authors demonstrate how MCF can identify which performance dimensions improve or remain limited as LLM layers are added and refined. The study shows that initial LLM integration enhances flow direction but worsens temporal occupancy and spatial distribution, while subsequent architectural tweaks recover these metrics and preserve flow gains.

arXiv Computation and Language
Oct 1

You're Hired: Strategic Model Selection for LLM Collaboration

arXiv:2609.38816v1 Announce Type: new Abstract: While multi-agent and model collaboration algorithms gain traction to combine the strengths of diverse Large Language Models (LLMs), existing systems r...

By Zongwan Cao, Ziyuan Yang, Shangbin Feng, Michael Duan, Skyler Hallinan, Bingbing Wen, Lucy Lu Wang, Yulia Tsvetkov
arXiv AI
Oct 23

Self-Improving Agents with World Model Predictive Paths

The paper introduces a test‑time framework that blends Model Predictive Path Integral (MPPI) control with a dual‑branch experience memory for large language model agents. At each decision step, the agent generates multiple candidate actions, uses a world model to simulate their outcomes, and evaluates these predictions for task progress and risk to select the best action. The dual‑branch memory allows the planner to refine action generation and the world model to improve future observation predictions, leading to strong performance on ALFWorld and ScienceWorld benchmarks.

By Haori Lu, Tianyu Gao, Yaoyao Liu, Yingying Li
arXiv Machine Learning
Oct 28

Intent-Preserving Adversarial User Simulation for Multi-Turn Agent Evaluation

The paper introduces StressSim, an intent‑preserving adversarial user simulator designed to stress‑test multi‑turn agents by generating challenging yet valid user interactions. StressSim optimises high‑level adversarial plans for each task instance using a genetic prompt‑optimisation loop that leverages rollout traces, task‑completion signals, and validity feedback to reduce task success while keeping the user’s goal unchanged. Experiments on MultiWOZ, retail, and airline domains show that StressSim reveals significant robustness gaps in leading LLM agents—reducing tau‑bench pass^4 scores by up to 69%—while maintaining realistic conversation quality and goal preservation with a modest optimisation budget.

By Atri Vivek Sharma, Brian Formento, Alessio Lomuscio
arXiv Computation and Language
5d ago

Agentic World Modeling for Agent Test-time Scaling without Environment Replica

Agentic World Modeling (AWM) redefines next-observation prediction as a multi-turn evidence-acquisition task, allowing agents to query a real environment safely and construct observations without mutating shared state. Integrated with trajectory-level test-time scaling, AWM enables parallel exploration over a single shared environment, outperforming single-shot simulation by 40.07% and trained world-model baselines by 12.36% on benchmarks such as τ-bench, AppWorld, and OfficeBench. This approach provides a practical foundation for safe and scalable agentic test-time scaling in shared, non-resettable environments.

By Wendi Li, Huseyin A. Inan, Wei-Ning Chen, Yanzhi Chen, Chetan Bansal, Saravan Rajmohan, Sharon Li