OpenAI Releases GPT-5.3-Codex Agentic Coding Model

OpenAI announced today the release of GPT-5.3-Codex, its most capable agentic AI coding model to date. The model combines GPT-5.2-Codex coding performance and GPT-5.2 reasoning capabilities, runs 25% faster, and can perform long-running research and tool-using tasks; OpenAI also used early model versions to accelerate development. It is available to paid ChatGPT users across app, CLI, IDE, and web, with API access forthcoming.