OpenAI has released GPT-5.3-Codex, its most capable agentic coding model to date. Announced on February 5, 2026, this revolutionary model represents a significant leap forward in AI-powered software development, combining frontier coding performance with advanced reasoning and professional knowledge capabilities. Available through Codex desktop app, plugins, and pi-coding-agent authentication, GPT-5.3-Codex is transforming how developers interact with AI coding assistants.