GPT-5.5 Pro
FrontierClosed weightsTextReasoning
GPT-5.5 Pro family model by OpenAI.
About the GPT-5.5 Pro family
The professional-grade tier of OpenAI's GPT-5.5 generation, run at extended reasoning effort for the hardest analytical tasks.
All GPT-5.5 Pro modelsHow this one is configured
This configuration runs in reasoning mode (thinks step-by-step before answering).
Also runs at: xhigh effort
Effort controls how long the model thinks before answering — higher effort usually means better answers on hard problems, at the cost of speed and money. Same model underneath, so they share this page.