Chroniclewatchgardn
Benchmark Breakdown • Software Engineering

Comparing Claude 3.5 Sonnet vs. GPT-4o for Code Refactoring & Architecture

By Chroniclewatchgardn Engineering Team • Published 2026

Code Synthesis and Large Language Models Visualization Interface

1. Introduction to the Benchmark Suite

As AI models transition into primary software development tools, engineering teams require rigorous empirical benchmarks beyond synthetic multiple-choice questions. In this study, we evaluated Anthropic Claude 3.5 Sonnet alongside OpenAI GPT-4o across 150 real-world software engineering repositories, testing multi-file refactoring, bug fixing, and framework translation.

2. Multi-File Context Retention & Accuracy

In refactoring exercises involving over 30 interrelated TypeScript and Rust modules, Claude 3.5 Sonnet demonstrated an exceptional 92.4% pass rate on first-attempt compilation compared to GPT-4o's 84.1%. Sonnet's ability to track variable scopes, type definitions, and subtle dependency imports across its 200,000-token window significantly reduced hallucinated methods.

Claude 3.5 Sonnet Score

92.4% First-Attempt

Flawless multi-file syntax adherence & state isolation.

GPT-4o Score

84.1% First-Attempt

Strong multi-modal image inputs and fast raw throughput.

3. Artifacts UI vs. Raw Streaming Output

Beyond backend logic, Anthropic's interactive Artifacts feature gave Claude 3.5 Sonnet a decisive UX edge. Software engineers can render React components, SVG architecture diagrams, and HTML web pages directly inside a live side-by-side sandbox, shortening feedback loops from minutes to seconds.

Verdict & Recommendations

While GPT-4o remains an extraordinary multi-modal utility, Claude 3.5 Sonnet takes the crown for dedicated code synthesis, structural refactoring, and complex architectural reasoning.

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