GPT-5.6 Sol is OpenAI's newest and most capable AI model, shipped on July 9, 2026 as part of the GPT-5.6 family. It replaced GPT-5.5 as the flagship, and it landed alongside ChatGPT Work, the merged desktop app, and the rename of connectors to Plugins.
Naming changed too. The number is the generation (5.5, 5.6). The name is a capability tier that carries across generations: Sol is the flagship, Terra is the balanced one, Luna is the fast cheap one.
What makes Sol special is that it actually understands what you are trying to accomplish. It plans the next steps, uses all of ChatGPT's built-in tools (web browsing, data analysis, file creation, code execution), checks its own work, and keeps going until the task is finished. You give it one prompt and it delivers a finished product.
The Big Picture
GPT-5.6 Sol leads OpenAI's lineup in coding, knowledge work, and reasoning, and it holds accuracy across very long context where earlier models fell apart. Hand it a full codebase, a 200-page contract, or a year of spreadsheets and it keeps track of the whole thing.
In practical terms, you can hand it a raw spreadsheet and say "analyze the trends and build me a full presentation with charts and recommendations" and it will actually do the entire thing. What used to take hours of back-and-forth now takes about two minutes with one prompt.
Who Gets Access
If you are not on a paid plan yet, ChatGPT Plus at $20/month is the move. Pro at $100/month is overkill unless you do deep research, complex math, or long multi-step workflows regularly.
How to Select GPT-5.6 Sol in ChatGPT
The old model picker is gone. You now pick a reasoning level, and the level decides which model runs.
Plus gets Instant, Medium and High. It does not get Extra High or Pro.
Sol, Terra and Luna
GPT-5.6 Sol is the flagship, and the only one of the three you can select in chat. Best for writing and debugging code, analyzing data and building charts, creating documents and presentations, and researching topics online.
GPT-5.6 Terra balances capability, speed and cost. Not selectable in chat. It shows up inside ChatGPT Work and Codex.
GPT-5.6 Luna is the fastest and cheapest of the family. Also not selectable in chat, also available inside Work and Codex on Plus and up.
Rule of thumb: stay on Medium for 90% of your work. Go to High when you catch yourself thinking "I really need this to be right," and save Pro for the genuinely hard stuff.
How to Prompt GPT-5.6 Sol
Using Sol for Data, Docs, and Presentations
Codex with GPT-5.6
Codex now lives inside the same merged desktop app as ChatGPT, and it pairs the GPT-5.6 family (Sol, Terra and Luna) with a coding-focused environment. It can write features, debug, refactor, open GitHub pull requests with clear descriptions, and run CI/CD-style automation. Use Fast Mode for interactive sessions where you are going back and forth rapidly.
10 Power User Tips
What Sol Is Not Great At (Yet)
It still has gaps with real-time visual reasoning, very niche domain expertise without uploaded references, and tasks that require live human judgment. Workaround: upload your own reference material and raise the reasoning level instead of hoping it guesses right.
Quick-Start Checklist
Get the Full Guide
Download the PDF below for the complete walkthrough with detailed examples, prompt templates, real-world use cases, and the 7 mistakes to avoid.