GPT-5.3 Codex vs Claude Opus 4.6: Full Comparison
February 07, 2026 · 5 min read
GPT-5.3 Codex and Claude Opus 4.6 both dropped on February 5, 2026 — within fifteen minutes of each other. Two frontier models, two very different strategies, one shared message: AI coding agents have arrived. Here’s how they compare, what each does best, and what these cloud giants mean for anyone who cares about running AI locally.