cfli/AREX-2

VISIONPricing:Input $1.6 / Cached $0.15 / Output $12Concurrent Unit Cost:2Model Size:27BQuant:FP8Context Size:32kTool Calling:SupportedPublished:Sep 29, 2026License:apache-2.0Architecture:Transformer Open Weights Featherless Exclusive Cold

AREX-2 is a 27 billion parameter multimodal agent model developed by the Beijing Academy of Artificial Intelligence (BAAI), built on a Dense Qwen3.8-compatible architecture. It specializes in long-horizon self-improvement, iteratively refining solutions by processing feedback such as scores, logs, and errors. This model excels at complex tasks requiring sustained reasoning, including algorithmic programming, machine-learning engineering, and deep research, demonstrating strong performance across these domains.

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AREX-2: Long-Horizon Self-Improving Agent

AREX-2 is a 27 billion parameter multimodal agent model from the Beijing Academy of Artificial Intelligence (BAAI), designed for long-horizon tasks. Built on a Dense Qwen3.8-compatible architecture, it features a substantial context length of 262,144 tokens.

Key Capabilities

  • Long-Horizon Self-Improvement: AREX-2 can refine solutions over multiple test-time rounds by proposing, measuring, reflecting, and revising.
  • Feedback-Driven Reflection: The model effectively uses various forms of feedback, including scores, logs, errors, and timings, to guide its iterative improvements.
  • Cross-Domain Performance: Trained on machine-learning and algorithmic-programming tasks, its self-improvement capabilities transfer effectively to deep research problems.
  • Sustained Reasoning: It maintains productive iteration even as task complexity and budget increase.

Evaluation Highlights

AREX-2 demonstrates strong performance across various benchmarks:

  • Coding & ML Engineering: Achieves 70.7 on Frontier-CS and 81.8 on MLE-Lite, outperforming many larger open-weight models.
  • General Agentic Reasoning & Deep Research: Scores 84.0 on BrowseComp, 52.6 on HLE, 92.2 on GAIA, and 93.8 on DeepSearchQA, competing favorably with frontier models in its size class.

Good for

  • Research into long-horizon agents and iterative problem-solving.
  • Machine-learning engineering and algorithmic coding tasks.
  • Tool-augmented deep research applications.