SWE-Bench ProMax: Benchmarking Agents on Large-Scale Multilingual Code Refactoring
TL;DR - SWE-Bench ProMax is an expert-curated, multilingual benchmark of 170 real-commit code-refactoring tasks designed to counter saturation and test-quality flaws in existing agent benchmarks. It matters because frontier models resolve only 41.2% of it, leaving a credible headroom signal for coding-agent progress.
- Motivated by an audit finding ~60% of unsolved SWE-bench Verified instances have flawed tests (overly narrow or overly broad), plus evidence that frontier models can verbatim reproduce gold patches from training data.
- Covers seven languages (Python, Java, TypeScript, Go, C, C++, Rust); each instance has issue descriptions rewritten from scratch and test suites manually reviewed to drop bad tests.
- Targets large-scale, behavior-preserving changes: instances average 11.4 modified files and 261.6 lines of code, with low-complexity or single-file tasks filtered out.
- Best frontier model reaches 41.2% resolve rate across two agent scaffolds; dataset is released on Hugging Face.