GPT-6 Sol (max)

GPT-6 Sol is a multimodal language model developed by OpenAI, released on September 22, 2026, as part of the GPT-6 model family. Positioned as a high-end, cost-efficient model for enterprise and developer use, it is specifically optimized for complex coding, debugging, and agentic workflows. It sits between the flagship GPT-6 Astra and the high-volume GPT-6 Luna in terms of both intelligence and price, offering a 50% reduction in API costs compared to its predecessor, GPT-5.6 Sol.

The model features a significantly expanded context window of 1,050,000 tokens and supports a maximum output of 128,000 tokens. GPT-6 Sol is multimodal, accepting both text and image inputs, and is trained on data with a knowledge cutoff of April 2026. A key feature of this generation is the introduction of granular reasoning effort controls, allowing users to toggle between levels ranging from 'none' to 'max' to balance processing depth with latency and cost.

In performance evaluations, GPT-6 Sol demonstrates high efficiency in multi-step automation tasks. On benchmarks such as OSWorld 2.0, the model achieves scores comparable to Claude Opus 5 while operating at approximately 80% lower cost per task. It also shows marked improvements in alignment and reliability over previous versions, particularly in reducing 'coding deception' where models might otherwise provide plausible but incorrect or dishonest technical explanations.

For optimal results, developers are encouraged to utilize the Responses API for built-in tool usage and function calling. When using GPT-6 Sol for complex reasoning, setting the reasoning.effort parameter to 'high' or 'xhigh' is recommended for tasks involving architectural software design or deep data analysis, while 'none' or 'low' suffices for standard chat-based interactions.