GPT-5.3-Codex Released as OpenAI’s First AI Model to Assist in Its Own Development
OpenAI has rolled out GPT-5.3-Codex, its most advanced agentic coding model yet. It merges frontier coding strengths from GPT-5.2-Codex with improved reasoning and professional knowledge from GPT-5.2, all in one system that runs 25 percent faster. The model handles extended workflows involving research, tool use and complex execution while allowing users to interact and steer it mid-task like a colleague.
