Scaling Test-Time Compute for Agentic Coding

Fuente: arXiv
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Main Authors: Kim, Joongwon, Yang, Wannan, Niu, Kelvin, Zhang, Hongming, Zhu, Yun, Helenowski, Eryk, Silva, Ruan, Chen, Zhengxing, Iyer, Srinivasan, Zaheer, Manzil, Fried, Daniel, Hajishirzi, Hannaneh, Arora, Sanjeev, Synnaeve, Gabriel, Salakhutdinov, Ruslan, Goyal, Anirudh
Format: Preprint
Published: 2026
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author Kim, Joongwon
Yang, Wannan
Niu, Kelvin
Zhang, Hongming
Zhu, Yun
Helenowski, Eryk
Silva, Ruan
Chen, Zhengxing
Iyer, Srinivasan
Zaheer, Manzil
Fried, Daniel
Hajishirzi, Hannaneh
Arora, Sanjeev
Synnaeve, Gabriel
Salakhutdinov, Ruslan
Goyal, Anirudh
author_facet Kim, Joongwon
Yang, Wannan
Niu, Kelvin
Zhang, Hongming
Zhu, Yun
Helenowski, Eryk
Silva, Ruan
Chen, Zhengxing
Iyer, Srinivasan
Zaheer, Manzil
Fried, Daniel
Hajishirzi, Hannaneh
Arora, Sanjeev
Synnaeve, Gabriel
Salakhutdinov, Ruslan
Goyal, Anirudh
contents Test-time scaling has become a powerful way to improve large language models. However, existing methods are best suited to short, bounded outputs that can be directly compared, ranked or refined. Long-horizon coding agents violate this premise: each attempt produces an extended trajectory of actions, observations, errors, and partial progress taken by the agent. In this setting, the main challenge is no longer generating more attempts, but representing prior experience in a form that can be effectively selected from and reused. We propose a test-time scaling framework for agentic coding based on compact representations of rollout trajectories. Our framework converts each rollout into a structured summary that preserves its salient hypotheses, progress, and failure modes while discarding low-signal trace details. This representation enables two complementary forms of inference-time scaling. For parallel scaling, we introduce Recursive Tournament Voting (RTV), which recursively narrows a population of rollout summaries through small-group comparisons. For sequential scaling, we adapt Parallel-Distill-Refine (PDR) to the agentic setting by conditioning new rollouts on summaries distilled from prior attempts. Our method consistently improves the performance of frontier coding agents across SWE-Bench Verified and Terminal-Bench v2.0. For example, by using our method Claude-4.5-Opus improves from 70.9% to 77.6% on SWE-Bench Verified (mini-SWE-agent) and 46.9% to 59.1% on Terminal-Bench v2.0 (Terminus 1). Our results suggest that test-time scaling for long-horizon agents is fundamentally a problem of representation, selection, and reuse.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16529
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Scaling Test-Time Compute for Agentic Coding
Kim, Joongwon
Yang, Wannan
Niu, Kelvin
Zhang, Hongming
Zhu, Yun
Helenowski, Eryk
Silva, Ruan
Chen, Zhengxing
Iyer, Srinivasan
Zaheer, Manzil
Fried, Daniel
Hajishirzi, Hannaneh
Arora, Sanjeev
Synnaeve, Gabriel
Salakhutdinov, Ruslan
Goyal, Anirudh
Software Engineering
Artificial Intelligence
Computation and Language
Machine Learning
Test-time scaling has become a powerful way to improve large language models. However, existing methods are best suited to short, bounded outputs that can be directly compared, ranked or refined. Long-horizon coding agents violate this premise: each attempt produces an extended trajectory of actions, observations, errors, and partial progress taken by the agent. In this setting, the main challenge is no longer generating more attempts, but representing prior experience in a form that can be effectively selected from and reused. We propose a test-time scaling framework for agentic coding based on compact representations of rollout trajectories. Our framework converts each rollout into a structured summary that preserves its salient hypotheses, progress, and failure modes while discarding low-signal trace details. This representation enables two complementary forms of inference-time scaling. For parallel scaling, we introduce Recursive Tournament Voting (RTV), which recursively narrows a population of rollout summaries through small-group comparisons. For sequential scaling, we adapt Parallel-Distill-Refine (PDR) to the agentic setting by conditioning new rollouts on summaries distilled from prior attempts. Our method consistently improves the performance of frontier coding agents across SWE-Bench Verified and Terminal-Bench v2.0. For example, by using our method Claude-4.5-Opus improves from 70.9% to 77.6% on SWE-Bench Verified (mini-SWE-agent) and 46.9% to 59.1% on Terminal-Bench v2.0 (Terminus 1). Our results suggest that test-time scaling for long-horizon agents is fundamentally a problem of representation, selection, and reuse.
title Scaling Test-Time Compute for Agentic Coding
topic Software Engineering
Artificial Intelligence
Computation and Language
Machine Learning
url https://arxiv.org/abs/2604.16529