arXiv AI

RobustSGPO: Search-Space Control for Agent Harness Evolution

RobustSGPO extends semantic‑gradient‑based prompt optimization (SGPO) by explicitly defining the edit scope, constructing and validating patches, and allowing search to resume from either the current or retained snapshots. In the AgentX brainstorming workflow, experiments on 120 tasks and 95 runs show that periodic permission scheduling improves test scores, while RobustSGPO raises completion rates on held‑out tasks from 60.0% to 80.0% and test quality from 3.77 to 4.14 within a 20‑million‑token budget. The approach also demonstrates that category‑based retention mitigates source‑task degradation after a shift, and that search‑space control enhances quality through executable edits and alternative starting points.

arXiv AI
4d ago

EvoFlux: Inference-Time Evolution of Executable Tool Workflows for Compact Agents

EvoFlux is an inference‑time search method that repairs tool‑use plans generated by small language models (1.5B‑4B parameters). It iteratively edits structured graphs of tool calls, guided by execution errors, to replace tools, correct parameters, insert missing steps, or remove redundancies. On the MCP‑Bench dataset, EvoFlux raises execution success from about 3% to 17‑24% across four small planners, outperforming supervised fine‑tuning baselines and matching or exceeding zero‑shot performance.

By Kushal Raj Bhandari, Ling Yue, Ching-Yun Ko, Dhaval Patel, Shaowu Pan, Pin-Yu Chen, Jianxi Gao
arXiv AI
Oct 1

Composing Task-specific Agent Harnesses at Test Time with Reusable Primitives

The paper introduces Harness Primitives—reusable agent harness mechanisms mined from failed task trajectories—and a framework called STITCH that selects and composes these primitives into task‑specific harnesses at test time. This approach avoids generating or debugging harness code for each task, achieving up to 12‑point gains in task success over fixed harness baselines and outperforming human‑designed harnesses like Codex CLI. STITCH also demonstrates minimal test‑time overhead (2.7%) and scales efficiently with the size of the primitive library.

By Peng Kuang, Haibo Jin, Dehao Wu, Feiyang Deng, Xiaopeng Yuan, Jerry Wang, Haohan Wang
arXiv AI
Jun 9

SWE-Marathon: Can Agents Autonomously Complete Ultra-Long-Horizon Software Work?

arXiv:2606. 07682v1 Announce Type: cross Abstract: AI agents are increasingly expected to complete long-horizon workflows that require sustained progress over hours, millions of tokens, and complex environments.

By Rishi Desai, Jesse Hu, Joan Cabezas, Neel Harsola, Pratyush Shukla, Roey Ben Chaim, Adnan El Assadi, Omkaar Mukund Kamath, Fenil Faldu, Prannay Hebbar, Jiankai Sun, Yiyuan Li, Pramod Srinivasan, Ishan Gupta, Christopher Settles, Daniel Wang, Derek Chen, Pranav Raja, Albert Liu, Marek \v{S}uppa, Nevasini Sasikumar, Luyang Kong, Erik Quintanilla, Xiangyi Li, Ivan Bercovich, Steven Dillmann
arXiv Machine Learning
Jul 10

TTHE: Test-Time Harness Evolution

arXiv:2607. 08124v1 Announce Type: cross Abstract: The behavior of an LLM agent is determined not only by the underlying model, but also by its harness: the executable program that constructs context, invokes tools, verifies intermediate results, and recovers from failures.

By Jun Nie, Yonggang Zhang, Jun Song, Qianshu Cai, Dahai Yu, Yike Guo, Xinmei Tian, Bo Han
Hugging Face Trending Papers
6d ago

Self-Evolving Agent Harness

The paper introduces the Self‑Evolving Agent Harness, a framework that allows an agent’s software scaffolding—prompts, memory, workflows, and executable components—to evolve while keeping the underlying model weights unchanged. It formalizes a feedback‑driven process where accepted revisions persist across runs, separating update targets from proposal and admission mechanisms, and distinguishes changes to interpreted state from revisions to tools and code. The authors analyze evolutionary search, provide generalization and retention bounds under PAC‑learning assumptions, and discuss the impact of persistent harness revisions on knowledge sharing, organizational workflows, and broader implications for scientific reliability, safety, and accountability.

arXiv AI
4d ago

Harness-Bench: Evaluating Agent Harnesses across Models and Realistic Workflows

Harness-Bench is a diagnostic benchmark that evaluates how different harness configurations affect LLM agent performance in realistic workflows. It tests 106 sandboxed offline tasks across multiple model backends, recording artifacts, execution traces, and usage statistics to analyze completion, process quality, efficiency, and failure behavior. The study finds significant variation in outcomes across model-harness pairings, indicating that agent capability should be reported at the configuration level rather than solely by the base model.

By Yilun Yao, Xinyu Tan, Chao-Hsuan Liu, Yaoming Li, Zhengyang Wang, Zongwei Lv, Wenhan Yu, Zhewen Tan, Yuxuan Tian, Lin Sun, Xiangzheng Zhang, Guangxiang Zhao, Tong Yang
arXiv Computation and Language
Aug 27

Scalable Supervision for Software Agents via Patch Reasoning

The paper introduces R4P, a reasoning‑based supervision method for software agents that eliminates the need for test execution by using a group‑wise training objective to verify multiple patches simultaneously. R4P achieves 72.2% accuracy on the SWE‑bench patch verification task, matching proprietary models, and enables the creation of an execution‑free scaffold called Mini‑SE. Mini‑SE, trained purely with reinforcement learning via R4P, improves Pass@1 from 26.2% to 32.8% over the baseline Qwen3‑32B, demonstrating R4P’s practical utility and scalable performance.

By Junjielong Xu, Boyin Tan, Xiaoyuan Liu, Chao Peng, Pengfei Gao, Pinjia He
arXiv AI
Oct 5

VERSE: Verified Self-Evolving Optimizer for Agent Harnesses

The paper introduces VERSE, a Verified Self‑Evolving optimizer that enhances LLM agent harnesses by allowing the optimizer to test edits, replay failures, and perturb steps while tracking fixes and regressions. VERSE builds its own tools for failure analysis, verification, training audits, and workflow control, and uses this feedback to revise the harness’s prompts, skills, tools, hooks, and notes without changing model weights. In experiments across five executors and multiple languages, VERSE improves all evaluated harness optimizers, achieving higher accuracy on held‑out and out‑of‑distribution tasks compared to the strongest baselines.

By Zekai Wang, Yingqiang Ge, Zekun Wang, Hai Wang, Yuhui Xu, Joshua Frandsen, Shancong Fu, Ashia C. Wilson, Chandan K. Reddy