GPT-5.3-Codex System Card
GPT-5.3-Codex System Card
AI summary
OpenAI released the System Card for GPT-5.3-Codex, stating that the model is the most capable agentic coding model to date, combining the frontier coding performance of GPT-5.2-Codex with the reasoning and expertise capabilities of GPT-5.2.
Why it was selected
The official System Card explains the source of GPT-5.3-Codex's capabilities, and can be compared with GPT-5.2-Codex and GPT-5.2 to understand the positioning of this generation of coding models.