tech
February 5, 2026
GPT-5.3-Codex System Card
GPT‑5.3-Codex is the most capable agentic coding model to date, combining the frontier coding performance of GPT‑5.2-Codex with the reasoning and professional knowledge capabilities of GPT‑5.2. This enables it to take on long-running tasks that involve research, tool use, and complex execution. Much like a colleague, you can steer and interact with GPT‑5.3-Codex while it’s working, without losing context.
TL;DR
- GPT‑5.3-Codex is the most capable agentic coding model currently available.
- It combines the coding performance of GPT‑5.2-Codex with the reasoning and professional knowledge of GPT‑5.2.
- Enables long-running tasks involving research, tool use, and complex execution.
- Allows for user interaction and guidance during operation without losing context.
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