ResearchResearch paperEfficiency & Inference · Training & Scaling · Safety & Alignment1 source · Oct 19, 2026

FrontierRefactor: Benchmarking Multi-Scale Performance-Oriented Codebase Refactoring

Autonomous codebase refactoring requires coding agents to restructure working software while strictly preserving externally observable behavior and prioritizing execution performance and compute efficiency over stylistic preference.

Key points

  • Existing benchmarks: refactoring benchmarks assess functional correctness while overlooking runtime regressions, whereas code performance benchmarks target isolated micro-kernels that ignore codebase-scale complexity.
  • We observe that refactoring scale is governed by the scope of the observable contract, the caller-visible interface fixing behavioral invariants while freeing private implementations for optimization.
  • Building on this insight, we introduce FrontierRefactor, a benchmark of 60 qualified engineering tasks spanning four scales, from computational kernels to full repositories, across in-place optimization and cross-language rewriting.
  • Evaluating frontier coding agents through a reference-free cascaded protocol across 1,080 execution runs reveals that correctness and speedup are largely decoupled: 41.2% of submissions satisfy functional equivalence yet fail to deliver verified performance improvements, with 19.3% suffering performance regressions and 21.9% trapped in measurement noise.

Sources (1)

  • [1]FrontierRefactor: Benchmarking Multi-Scale Performance-Oriented Codebase Refactoring
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 19, 05:47 AM
    Autonomous codebase refactoring requires coding agents to restructure working software while strictly preserving externally observable behavior and prioritizing execution performance and compute efficiency over stylistic preference.
    Existing benchmarks: refactoring benchmarks assess functional correctness while overlooking runtime regressions, whereas code performance benchmarks target isolated micro-kernels that ignore codebase-scale complexity.

Extractive summary: sentences quoted from the sources.

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