ACC: Compiling Agent Trajectories for Long-Context Training

Fuente: arXiv
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Main Authors: Su, Qisheng, Fang, Zhen, Huang, Shiting, Zeng, Yu, Zhao, Yiming, Shi, Kou, Zhang, Ziao, Chen, Lin, Chen, Zehui, Wu, Lijun, Zhao, Feng
Format: Preprint
Published: 2026
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author Su, Qisheng
Fang, Zhen
Huang, Shiting
Zeng, Yu
Zhao, Yiming
Shi, Kou
Zhang, Ziao
Chen, Lin
Chen, Zehui
Wu, Lijun
Zhao, Feng
author_facet Su, Qisheng
Fang, Zhen
Huang, Shiting
Zeng, Yu
Zhao, Yiming
Shi, Kou
Zhang, Ziao
Chen, Lin
Chen, Zehui
Wu, Lijun
Zhao, Feng
contents Recent development of agents has renewed demand for long-context reasoning capacity of LLMs. However, training LLMs for this capacity requires costly long-document curation or heuristic context synthesis. We observe that agents produce massive trajectories when solving problems, invoking tools and receiving environment observations across many turns. The evidence needed to answer the original question is thus scattered throughout these turns, requiring integration of distant context segments. Nevertheless, standard agent SFT masks tool responses and only trains turn-level tool selection, creating a supervision blind spot where these scattered signals go unused. We propose Agent Context Compilation (ACC), which converts trajectories from search, software engineering, and database querying agents into long-context QA pairs that combine the original question with tool responses and environment observations gathered across multiple turns, training the model to answer directly without tool use. This makes the dependencies between the question and the evidence explicit, enabling direct supervision of long-context reasoning over distant segments without additional annotation. ACC is a simple but effective approach that can be combined with any existing long-context extension or training method, providing scalable supervised fine-tuning data. We validate ACC on long-range dependency modeling tasks through MRCR and GraphWalks, challenging benchmarks requiring cross-turn coreference resolution and graph traversal over extended contexts. Training Qwen3-30B-A3B with ACC achieves 68.3 on MRCR (+18.1) and 77.5 on GraphWalks (+7.6), results comparable to Qwen3-235B-A22B, while preserving general capabilities on GPQA, MMLU-Pro, AIME, and IFEval. Further mechanism analysis reveals that the ACC-trained model exhibits task-adaptive attention restructuring and expert specialization.
format Preprint
id arxiv_https___arxiv_org_abs_2605_21850
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ACC: Compiling Agent Trajectories for Long-Context Training
Su, Qisheng
Fang, Zhen
Huang, Shiting
Zeng, Yu
Zhao, Yiming
Shi, Kou
Zhang, Ziao
Chen, Lin
Chen, Zehui
Wu, Lijun
Zhao, Feng
Computation and Language
Artificial Intelligence
Recent development of agents has renewed demand for long-context reasoning capacity of LLMs. However, training LLMs for this capacity requires costly long-document curation or heuristic context synthesis. We observe that agents produce massive trajectories when solving problems, invoking tools and receiving environment observations across many turns. The evidence needed to answer the original question is thus scattered throughout these turns, requiring integration of distant context segments. Nevertheless, standard agent SFT masks tool responses and only trains turn-level tool selection, creating a supervision blind spot where these scattered signals go unused. We propose Agent Context Compilation (ACC), which converts trajectories from search, software engineering, and database querying agents into long-context QA pairs that combine the original question with tool responses and environment observations gathered across multiple turns, training the model to answer directly without tool use. This makes the dependencies between the question and the evidence explicit, enabling direct supervision of long-context reasoning over distant segments without additional annotation. ACC is a simple but effective approach that can be combined with any existing long-context extension or training method, providing scalable supervised fine-tuning data. We validate ACC on long-range dependency modeling tasks through MRCR and GraphWalks, challenging benchmarks requiring cross-turn coreference resolution and graph traversal over extended contexts. Training Qwen3-30B-A3B with ACC achieves 68.3 on MRCR (+18.1) and 77.5 on GraphWalks (+7.6), results comparable to Qwen3-235B-A22B, while preserving general capabilities on GPQA, MMLU-Pro, AIME, and IFEval. Further mechanism analysis reveals that the ACC-trained model exhibits task-adaptive attention restructuring and expert specialization.
title ACC: Compiling Agent Trajectories for Long-Context Training
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2605.21850