Which AI model should engineering teams use for real-world coding: Claude Opus 4.5, GPT-5.1 (Codex-Max), or Gemini 3 Pro? In the last few months the big language models landscape has shifted fast. If your engineering team must pick a model for real-world software work — debugging multi-file repositories, refactoring architecture, building agentic automation, or generating dynamic UIs — the choice matters. This guide compares three current leaders (Claude Opus 4.5, GPT-5.1 Cod