Kodezi Chronos: A Debugging-First Language Model for Repository-Scale Code Understanding

TL;DR

Kodezi Chronos-1 is a specialized debugging language model capable of understanding and fixing complex multi-file bugs in large codebases, significantly outperforming existing models on real-world debugging tasks.

Contribution

Introduction of Kodezi Chronos-1, a debugging-focused language model with adaptive retrieval, persistent debug memory, and a fix-test-refine architecture for large-scale code understanding.

Findings

Achieves 67.3% fix accuracy on real-world scenarios

Reaches 80.33% resolution rate on SWE-bench Lite

Reduces debugging time by 40% and iterations by 65%

Abstract

Large Language Models (LLMs) have advanced code generation and software automation but remain constrained by inference-time context and lack structured reasoning over code, leaving debugging largely unsolved. While Claude 4.5 Opus achieves 74.40% on SWE-bench Verified and Gemini 3 Pro reaches 76.2%, both models remain below 20% on real multi-file debugging tasks. We introduce Kodezi Chronos-1, a language model purpose-built for debugging that integrates Adaptive Graph-Guided Retrieval to navigate codebases up to 10 million lines (92% precision, 85% recall), Persistent Debug Memory trained on over 15 million sessions, and a seven-layer fix-test-refine architecture. On 5,000 real-world scenarios, Chronos-1 achieves 67.3% +/- 2.1% fix accuracy compared to 14.2% +/- 1.3% for Claude 4.1 Opus and 13.8% +/- 1.2% for GPT-4.1 (Cohen's d = 3.87). On SWE-bench Lite, Chronos-1 reaches a state-of-the-art 80.33% resolution rate (241 of 300), outperforming the next best system by 20 points and achieving repository-specific highs of 96.1% on Sympy and 90.4% on Django. Chronos-1 reduces debugging time by 40% and iterations by 65%, resolving complex multi-file and cross-repository bugs that require temporal analysis. Limitations remain for hardware-dependent and dynamic language errors, and Chronos-1 will be available in Kodezi OS in Q4 2025 and via API in Q1 2026.