Claude 4.6 Opus beats GPT-5 in codebase refactor

Claude Opus 4.6 marks the transition from "chat assistant" to "autonomous engineer," managing architectural scale previously impossible for LLMs. The 1M token context window effectively eliminates the need for aggressive RAG in medium-sized codebases, while the Adaptive Thinking mode allows the model to "pause and plan" before executing complex multi-file operations. This model reduces "context rot" to ensure structural consistency across thousands of lines of refactored code, outperforming GPT-5 in structural tasks and providing standard pricing for long-context production workflows.