GPT-5.5: Capabilities and Reactions

GPT-5.5: Capabilities and ReactionsZvi MowshowitzApr 28, 20261441ShareThe 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 agent tasks, including computer use.This is the first time since Claude Opus 4.5 came out, so in about four months, that I’ve considered a non-Anthropic model a competitive choice outside of some narrow tasks like web search. GPT-5.5 is not perfect, nor is it the best at everything, but basically everyone thinks this is a solid upgrade. Highly positive overall feedback. My effective usage is now split between the two, depending on the nature of the task. If it’s something that can be well-specified and all I want is the right answer, my instinct is I go with GPT-5.5. If I’m not sure what exactly I want, or I want to have a conversation, or I want to do Claude Code shaped things, I go with Opus 4.7. As always, try the models, test your use cases, and see what you think.OpenAI reports this is a new base model, codenamed Spud, and predicts rapid iteration from here. One wonders if that means this move was a relatively large raw intelligence boost, whereas the next few iterations will be about functionality. Price is $5/$30 per million tokens, or for Pro you pay $30/$180. OpenAI says that token use is more efficient now, so the headline price went up but real costs went down.The Official PitchThe focus is on using your computer, coding, research and getting work done.They’re also claiming a ‘much higher’ level of intelligence versus GPT-5.4.As always, listen to the pitch, hear what they say and also what they don’t say.OpenAI: We’re releasing GPT‑5.5, our smartest and most intuitive to use model yet, and the next step toward a new way of getting work done on a computer.GPT‑5.5 understands what you’re trying to do faster and can carry more of the work itself. It excels at writing and debugging code, researching online, analyzing data, creating documents and spreadsheets, operating software, and moving across tools until a task is finished. Instead of carefully managing every step, you can give GPT‑5.5 a messy, multi-part task and trust it to plan, use tools, check its work, navigate through ambiguity, and keep going.The gains are especially strong in agentic coding, computer use, knowledge work, and early scientific research—areas where progress depends on reasoning across context and taking action over time. GPT‑5.5 delivers this step up in intelligence without compromising on speed: larger, more capable models are often slower to serve, but GPT‑5.5 matches GPT‑5.4 per-token latency in real-world serving, while performing at a much higher level of intelligence. It also uses significantly fewer tokens to complete the same Codex tasks, making it more efficient as well as more capable.We are releasing GPT‑5.5 with our strongest set of safeguards to date, designed to reduce misuse while preserving access for beneficial work.​Greg Brockman (President OpenAI): Codex + 5.5 is incredible for the full spectrum of computer use. No longer just for coders, but for anyone who does computer work…

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