GPT-5.5: Capabilities and Reactions

The system card for GPT-5.5 mostly told us what we expected. See this thread from Drake Thomas for some comparisons to Anthropic’s model card for Opus 4.7. Now we move on to asking what it means in practice, and in what situations GPT-5.5 should become our new weapon of choice. My answer is for some purposes yes, and for others no, but it is now competitive. GPT-5.5 is like GPT-5.4, only more so, and with improved capabilities in particular on raw intelligence and for well-specified coding and a...