GPT-5.1 Thinking
GPT-5.1 Thinking is a reasoning-focused model that uses chain-of-thought processing to solve complex problems. It bridges the gap between standard text models and dedicated reasoning models like o3, offering solid analytical capabilities at a lower compute cost.
Thinking mode produces transparent reasoning traces, making it valuable for applications requiring explainable AI.
Key Features
Chain-of-thought reasoning with visible traces
Strong math and logic performance
128K token context window
Adjustable thinking depth
More affordable than o3 for reasoning tasks
Ideal Use Cases
Analytical tasks requiring step-by-step reasoning
Math tutoring with worked solutions
Logic puzzles and constraint satisfaction
Explainable AI for compliance workflows
Example Prompts for GPT-5.1 Thinking
Technical Specifications
| Context Window | 128K tokens |
| Modality | Text → Text |
| Provider | OpenAI |
| Category | Reasoning |
| Thinking Mode | Built-in |
| Max Output | 32K tokens |
Frequently Asked Questions
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