Key takeaways

• GPT-5.3 Chat is designed for everyday conversational AI, aiming for smoother, more useful, and directly helpful interactions by providing accurate answers with better contextualization.
• The model seeks to solve the problem of interrupted conversational flow by significantly decreasing unnecessary refusals, caveats, and overly cautious phrasing.
• It is a proprietary, Transformer-based model using a Mixture of Experts (MoE) architecture developed by OpenAI, with a context length of 128,000 and a maximum token output of 16,384.
• In mathematical problem-solving, the model demonstrates strong foundational understanding with high accuracy in lower to intermediate difficulty levels, particularly in Number Theory and most Algebra levels across various categories of the MATH benchmark (e.g., 100% accuracy in Algebra_level_1, Counting & Probability_level_1, Prealgebra_level_1, Precalculus_level_1, and in Number Theory levels 1, 2, 3, and 5).
• Key limitations include significant struggles with quantitative problems and highly specific domain knowledge across diverse academic subjects (as seen in the 'Humanity's Last Exam' with an overall score of ~9.36%), misinterpretation of geometric conditions, occasional issues with final answer formatting in math problems (e.g., Geometry problems at higher levels like level 4 and 5 at 66.7% and level 1 at 50% accuracy), and inaccurate image analysis for multimodal questions.

Technical specifications

Context length

128k tokens

Max output

—

Architecture

MoE

Modalities

text+image->text

Parameters

—

Open weights

No

Licence

Proprietary

Regions

USA

Vendor

OpenAI

Provider model key

openai/gpt-5.3-chat