o3-mini-2025-01-31 with high reasoning effort replied with "Hi" after 448 reasoning tokens.

gpt-4.5-preview-2025-02-27 replied with "Hi!"

> o3-mini-2025-01-31 with high reasoning effort replied with "Hi" after 448 reasoning tokens.

I got "hi", as expected. What is the full system prompt + user message you're using?

https://i.imgur.com/Y923KXB.png

> gpt-4.5-preview-2025-02-27

Same "hi": https://i.imgur.com/VxiIrIy.png

Ah right, my bad. Somehow I thought the prompt was only:

    Say just 'hi'

while the "without any extra words or explanations" part was for the readers of your comment. Perhaps kubb also made a similar mistake.

I used empty system prompt.