ChatGPT-5.3-Codex Is Also Good At Coding
The AI coding wars just escalated with a new, specialized model claiming to be your 'colleague'.
Deep Dive
OpenAI launched GPT-5.3-Codex on February 13, 2026, directly competing with Anthropic's same-day release of Claude Opus 4.6. The model combines GPT-5.2-Codex's coding skills with GPT-5.2's general reasoning for long-running, agentic tasks. It's exclusive to the Codex app, which saw 1 million downloads, and integrates with Cursor, GitHub, and VS Code. OpenAI claims it's the 'most capable agentic coding model,' but provided fewer benchmarks than Anthropic's detailed 212-page system card.
Why It Matters
Developers now have two top-tier, specialized AI 'colleagues' for complex coding tasks, forcing a direct comparison and choice in tools.