arXiv AI

TurnCost: Turns, Not Observations: Cache-Aware Loop Engineering for Coding Agents

arXiv AI
Oct 15

LoopArena: Benchmarking Models as Runtime Controllers for Loop Engineering

LoopArena is a benchmark that evaluates how effectively a model (the Controller) can guide a separate coding agent (the Worker) through long-running tasks by monitoring progress, assigning work, and deciding when to stop. It consists of three settings: Type I with 160 low‑cost control questions, Type II with 80 task slices, and Type III with 80 full tasks. In full tasks, the best observed strict success rate is 36.25%, and Controllers can reduce inference cost by an average of 60.6% while maintaining a strong correlation in performance ranking.

By Yi Wang, Haopeng Zhang, Chengxiang Huang, Rui Dai, Kaikui Liu, Piotr Koniusz, Xiangxiang Chu
arXiv AI
Oct 5

What Does a Token Cost? A Mixture-of-Agents Measurement of Sufficient Per-Token Compute

The paper introduces a Mixture-of-Agents (MoA) approach to quantify the per-token compute required by large language models. By having a panel of fifteen models of varying sizes attempt to reproduce each token, the authors define the smallest successful agent’s inference cost as the token’s sufficient compute, providing an upper bound on necessary computation. Experiments on benchmarks show that a 0.5B model can reproduce most tokens, and that the MoA-derived compute map can reduce latency in model routing and drafting tasks while improving or maintaining accuracy.

By Zhixu Du, Weijia Han, Hai Helen Li, Yiran Chen
arXiv AI
Oct 5

How Do AI Agents Spend Your Money? Analyzing and Predicting Token Consumption in Agentic Coding Tasks

The paper presents a systematic study of token consumption in AI agents performing coding tasks. It finds that agentic tasks are far more expensive—about 1000 times more tokens than code reasoning or chat—primarily due to input tokens, and that token usage varies wildly, with accuracy peaking at moderate costs. Models differ significantly in efficiency, and current frontier models cannot reliably predict their own token usage, often underestimating it.

By Longju Bai, Zhemin Huang, Xingyao Wang, Jiao Sun, Rada Mihalcea, Erik Brynjolfsson, Alex Pentland, Jiaxin Pei
arXiv AI
Oct 2

Agents Are Systems, Not Models: Rethinking Agentic Evaluation

The paper argues that evaluating agents as fixed models is insufficient, proposing instead to treat them as configurable systems. Using a new benchmark of four scientific tasks, the authors analyze how five configuration aspects—task information, reasoning, self‑verification, time budget, and backbone model—affect performance, noting that about 54% of outcome variance arises from run‑to‑run differences even with the same settings. The study finds that providing more task information has the strongest impact, while interactions among settings (e.g., extra time only helps with adequate information or model capability) and the choice of verification tools significantly shape agent behavior.

By Luis Wiedmann, Leander Girrbach, Cordelia Schmid, Zeynep Akata
arXiv AI
Sep 28

Analyzing and Mitigating Cost-Inefficient Behaviors in Coding Agents

The paper investigates cost-inefficient behaviors in coding agents, analyzing 1,200 trajectories from Claude Code and Mini-SWE-Agent on SWE-bench Verified. It identifies three main inefficiencies—subsumed retrieval, similar script generation, and test re-execution—that affect 79–98% of tasks and contribute up to 22.75% of costs. The study evaluates mitigation strategies, finding that developer-designed skills reduce costs by up to 41.73%, outperforming other approaches.

By Yiran Hu, Nan Jiang, Shanchao Liang, Anik Dey, Yi Wu, Lin Tan
arXiv AI
Sep 18

An Empirical Study of Harness Design for Coding Agents

The study investigates how individual components of a coding harness—planning, action space, and context management—affect autonomous coding agents’ performance. By fixing the execution loop and varying these components across 176 settings on SWE‑Bench Verified and Terminal‑Bench 2.1, the authors find that context management is most valuable when context windows are tight, staging rule‑based elision before LLM summarization yields the best efficiency, planning serves as an accuracy scaffold for weaker models and a cost saver for stronger ones, and predefined tools help models with limited bash skills while bash‑capable models benefit from a bash‑only interface. Trajectory‑level analysis shows that context management lengthens execution paths, planning alters where trajectories terminate, and the action space determines code granularity, offering a modular framework for future harness design.

By Run-Ze Fan, Zihao Zhang, Simin Ma, Yebowen Hu, Shouju Wang, Kaiqiang Song, Fei Liu, Hamed Zamani, Xiaoyang Wang