INTRODUCING GPT-5.3-CODEX

Summary from the TLDR newsletter

GPT-5.3-Codex is OpenAI's most capable agentic coding model to date. It advances both the frontier coding performance of GPT-5.2-Codex and the reasoning and professional knowledge capabilities of GPT-5.2 while being 25% faster. The model can take on long-running tasks that involve research, tool use, and complex execution. Developers can steer and interact with the model while it's working without losing context.