GPT‑5.6 Sol is OpenAI’s flagship model in the GPT‑5.6 family. It is designed for complex professional work that requires advanced reasoning, coding, tool use, and analysis of text and images.
What is GPT‑5.6 Sol?
OpenAI launched the GPT‑5.6 family on July 9, 2026. The family includes Sol for flagship capability, Terra for a balance of capability and cost, and Luna for fast, cost-sensitive workloads.
Capabilities
The model accepts text and images and produces text. Through the OpenAI API it supports function calling, structured outputs, web and file search, code execution, hosted shell, and computer use. It also offers several reasoning-effort levels.
Context and output
OpenAI documents a 1,050,000-token context window and up to 128,000 output tokens. This is useful for long documents and large codebases, but a large context window does not guarantee factual accuracy.
Pricing
The official model page lists promotional API pricing of $4 per million input tokens, $0.40 per million cached-input tokens, and $20 per million output tokens, available until at least November 21, 2026. Requests above 272,000 input tokens use higher long-context pricing.
Strengths and limitations
Its main strengths are long context, strong reasoning and coding, and broad tool support. Its trade-offs include a higher price than Terra and Luna, no direct audio or video support, and the continuing need to verify important outputs.
In short
GPT‑5.6 Sol is best suited to demanding work where capability matters more than minimum cost.