What was pitched as the biggest computing project in history is now facing delays, internal skepticism, and growing competitive pressure.

The app is powered by GPT-5.2-Codex, OpenAI’s newest programming-focused large language model. It can process prompts with up to 400,000 tokens, which corresponds to about 100,000 lines of code, and understands over 50 programming languages. Users can also upload multimodal input such as interface sketches.