Model · OpenAI · Text
GPT-5.6 Sol
The frontier tier of OpenAI's GPT-5.6 family — built for complex professional work: deep reasoning, coding, scientific analysis, and long-running agentic tasks. Sits below GPT-6 Astra (2026-09-03) and alongside, not as a replacement for, GPT-5.5.
- Modality
- Text
- License
- Proprietary (Proprietary)
- Context window
- 1,050,000 tokens
- Released
- July 9, 2026
- Last verified
- September 8, 2026
- Runs locally
- No
- Also handles
- vision
Strengths
- Frontier tier of the GPT-5.6 family for complex professional work
- 1.05M-token context window (128k max output)
- February 2026 knowledge cutoff
- Vision-enabled; supports function calling, web search, file search, and computer use
Weaknesses
- Closed weights — API/product only
- Premium pricing ($4 input / $20 output per MTok, promotional at least through 2026-11-21)
- Superseded at the top of the lineup by GPT-6 Astra (2026-09-03)
Try it
| Where | Type | Notes |
|---|---|---|
| OpenAI API | hosted-api | API key required |
Used in solutions
Version history
- GPT-5.6 Luna Jul 2026
- GPT-5.6 Sol Jul 2026 Current
- GPT-5.6 Terra Jul 2026
- GPT-5.5 Apr 2026
- GPT-5.4 mini Mar 2026
Official sources
- Model docs docs
- API changelog (release note) announcement
Change log
- — Pricing corrected to $4 input / $20 output per MTok — OpenAI cut Sol's rates on 2026-08-21 (promotional at least through 2026-11-21); the entry carried the July launch prices. Repositioned below GPT-6 Astra (released 2026-09-03).
- — Initial entry. GPT-5.6 family released 2026-07-09 per OpenAI's API changelog; specs and pricing verified against the gpt-5.6-sol model docs. API alias is `gpt-5.6`.
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