GPT-5 pro. Here's OpenAI's model documentation for their GPT-5 pro model, released to their API today at their DevDay event.
It has similar base characteristics to GPT-5: both share a September 30, 2024 knowledge cutoff and 400,000 context limit.
GPT-5 pro has maximum output tokens 272,000 max, an increase from 128,000 for GPT-5.
As our most advanced reasoning model, GPT-5 pro defaults to (and only supports)
reasoning.effort: high
It's only available via OpenAI's Responses API. My LLM tool doesn't support that in core yet, but the llm-openai-plugin plugin does. I released llm-openai-plugin 0.7 adding support for the new model, then ran this:
llm install -U llm-openai-plugin
llm -m openai/gpt-5-pro "Generate an SVG of a pelican riding a bicycle"
It's very, very slow. The model took 6 minutes 8 seconds to respond and charged me for 16 input and 9,205 output tokens. At $15/million input and $120/million output this pelican cost me $1.10!
Here's the full transcript. It looks visually pretty simpler to the much, much cheaper result I got from GPT-5.
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