GPT Sol — OpenAI's top-tier line | Lexicon
Current
“Sol” is the name of a line, not a single model. The current flagship is GPT Sol version 5.6 (released July 9, 2026). Concrete figures on price, context window and benchmarks for the running version live in the glossary entry GPT Sol — this hub explains the line as a whole.
What GPT Sol is
GPT Sol is the top of the three tiers OpenAI splits its GPT-5.6 family into: Luna for speed and cost, Terra as the balanced middle, Sol for the hardest work. The name stays constant across generations — only the version number behind it moves up. So when you read “Sol”, you are not pointing at a fixed model but at the permanent top-tier slot in the OpenAI lineup.
That split is deliberate. Instead of a single do-everything model you get three clearly positioned tools, and Sol is the one you pay the most for and that returns the deepest reasoning and coding of the family in exchange.
Positioning
Sol sits in the frontier band: high capability, moderate speed, a correspondingly high price per token. The suitability profile shows the pattern at a glance — strong on coding and reasoning, more reserved on speed and cost efficiency.
Eignung 0–5 · redaktionelle Einordnung, kein Benchmark
The axes are an editorial assessment, not a benchmark. They help with rough orientation but do not replace your own test on the concrete use case.
Use profile
Sol pays off where output quality and reliability across many steps matter:
- Heavy coding agents that hold context over long chains and tolerate little rework.
- Deep research and analysis where a wrong conclusion is expensive — legal, scientific or safety-critical work.
- Tasks with high consistency demands, such as architecture decisions or large refactorings.
For everyday and high-volume work — classification, summaries, simple assistants — Sol is oversized. There, Terra or Luna carries the same load at a fraction of the cost.
Sol also offers a compute-heavy Ultra mode with greater reasoning depth. It costs the same per token as the base variant but answers more slowly — meant for cases where maximum quality beats speed.
Selection guide
The positioning map places Sol against its two family siblings and one external frontier model. The question is rarely “which model is best” but “which tier fits this task”:
Redaktionelle Einordnung, kein Benchmark
Rule of thumb: start at the bottom and only work up as far as the task demands. If Luna handles a task reliably, you do not need Sol. If Terra shows weaknesses in multi-step reasoning, Sol is the next step. And because this market turns over fast, model choice belongs in one central, configurable place in your system — not hard-wired into individual calls.
More in the glossary
- GPT Sol — current version, price, context window and benchmarks
- GPT Terra — the balanced middle of the family
- GPT Luna — the fast, low-cost entry tier
FAQ
- All three belong to the GPT-5.6 family but differ in capability, speed and price. Luna is tuned for speed and cost, Terra is the balanced default, Sol delivers the deepest reasoning and coding of the three — at a correspondingly higher price per token.
- A line name. Sol permanently denotes OpenAI's top tier; the version number behind it (currently 5.6) changes with each generation without the line's name changing.
- Those where output quality and reliability across many steps count — heavy coding agents, deep scientific research or safety-critical analysis. For everyday and high-volume tasks, Terra or Luna is the more economical choice.
- A compute-heavy setting with greater reasoning depth, at the same per-token price as the base variant but with longer response times — meant for tasks where maximum quality beats speed.
- This hub covers the line as a whole. Details on price, context window and benchmark values for the current version live in the linked glossary entry [GPT Sol](/en/app/glossar/gpt-sol/).