OpenAI Releases GPT-5.3-Codex, Anthropic Unveils Opus 4.6

OpenAI and Anthropic released competing AI models on Thursday: OpenAI unveiled GPT-5.3-Codex, a faster, more efficient coding-focused model with a standalone desktop app, while Anthropic launched Claude Opus 4.6, adding a larger context window for longer documents and productivity tasks. The launches coincided with back-to-back podcast appearances and ad-driven marketing jabs over ChatGPT's planned ads, highlighting intensified commercial rivalry.