One of the notable shifts is the dynamic allocation of ChatGPT thinking time depending on task complexity . For lightweight requests, GPT 5 Codex behaves quickly and responsively, whereas for more complex jobs it allocates more reasoning, iterations, and internal editing. In internal testing, OpenAI was able to achieve more than seven continuous hours of autonomous work, using ChatGPT to iteratively refine solutions, address test failures, and ship valid implementations. On code reviews, GPT 5
