Abstract
Recent progress on ARC-AGI-1 has broadly come from two regimes: heavy test-time compute over frontier models (evolutionary search, exhaustive sampling, extended chain-of-thought), or benchmark-specific training where small models are fine-tuned on ARC data, often with task-specialized architectures. We study a third regime: an open-weight model in non-thinking mode (DeepSeek V3.2) under a strict budget, with no ARC-specific fine-tuning.
We explore what can be recovered through architecture alone, constructing agentic harnesses that explicitly decompose pattern-discovery and program-synthesis stages. First, we introduce an Explorer-Definer Pipeline that separates pattern discovery from executable transformation synthesis, implemented as a two-stage agent pipeline. Next, we present the Reflective Orchestrator, which augments the pipeline with autonomous exploration of new transformations when previous hypotheses fail on training pairs.
On the ARC-AGI-1 public 400-task evaluation set, the pipeline reaches 57.50% pass@2 at $0.25 per task, and the orchestrator reaches 67.25% pass@2 at $0.62 per task. Together these architectures lift a 15.50% one-shot baseline by ~52 points without benchmark-specific training or heavy test-time compute. Furthermore, the orchestrator-driven lift tests a falsifiable diagnostic the pipeline produces; unbiased pass@k analysis suggests the pipeline is generation-bound, not selection-bound (selection via training-pair accuracy captures ~95% of the candidate ceiling) and predicts that significant improvement requires broader generation, not better ranking. The orchestrator implements this prediction via adaptive re-exploration and confirms it (unbiased pass@1 lift +9.81 pp, matching selection-mediated pass@2 lift). An additional pipeline ablation identifies its think tool as a significant component, with removal reducing pass@2 by 5.75 pp.
Blogger's Review: This study showcases the potential for significant performance improvements through innovative architectural designs without relying on specific training, emphasizing the importance of generative capabilities rather than just selection mechanisms. It points future research in a promising direction, especially in optimizing model performance under resource constraints.