OpenAI Launches GPT-5.3 Codex Amid Anthropic’s Earlier Agentic Coding Release

OpenAI announced the release of GPT-5.3 Codex, an advanced agentic coding model that expands Codex’s capabilities beyond writing and reviewing code to nearly any professional computing task. The model claims to generate highly functional complex games and apps from scratch in days, is 25% faster than GPT-5.2, and was instrumental in its own creation through self-debugging and performance evaluation. The update follows a closely timed competition with Anthropic, whose release of its agentic coding model was moved up by 15 minutes from the originally scheduled 10:00 a.m. PST on February 5, 2026, just before OpenAI’s announcement.