GPT-5.6 Sol
GPT-5.6 Sol is the flagship tier of OpenAI’s GPT-5.6 family. It leads the family on every benchmark and is built for the tasks where correctness matters more than cost: frontier coding, long-horizon agentic work, scientific research, and cybersecurity.
The GPT-5.6 family
GPT-5.6 ships as three tiers. The number is the generation; the name is the capability tier, so each tier can advance on its own schedule.
- Sol (this model) — the flagship, for the hardest work.
- Terra — balanced, for everyday production. GPT-5.5-level quality at roughly half the cost.
- Luna — fast and affordable, for high-volume, latency-sensitive work.
Reasoning effort
Control how long the model reasons before answering with the reasoning_effort parameter:
| Level | Description |
|---|---|
none (default) |
Fast, low-latency responses |
low |
Light reasoning with minimal overhead |
medium |
Balanced reasoning and speed |
high |
Thorough multi-step reasoning |
xhigh |
Maximum reasoning depth for the hardest problems |
For higher reasoning efforts, you may need to increase max_completion_tokens to avoid empty responses where all tokens are used on reasoning.
Verbosity
Control output length with the verbosity parameter:
- low: Concise, to-the-point answers
- medium (default): Balanced responses
- high: Detailed, comprehensive explanations
Input and output
- Input: Text, images
- Output: Text
Pricing
| Per 1M tokens | |
|---|---|
| Input | $5.00 |
| Cached input | $0.50 |
| Output | $30.00 |
Links
Model created