GPT-5.1
OpenAI
OpenAI's flagship model optimized for coding and agentic workflows with adaptive reasoning. Two variants (Instant and Thinking) balance speed and thoroughness. Instant tier features breakthrough adaptive reasoning that automatically decides when to think deeply versus respond quickly. Thinking tier provides persistent reasoning for complex multi-step problems. Strong improvements on math and coding benchmarks including AIME 2025 and Codeforces.
Strengths
- Adaptive reasoning in Instant tier - automatically chooses when to think deeply vs respond quickly
- Strong coding performance with significant AIME 2025 and Codeforces improvements
- 200K context window sufficient for most use cases while maintaining performance
- Thinking tier provides persistent reasoning for complex multi-step problems
- More cost-effective than GPT-5.2 while maintaining high quality ($1.25 vs $1.75 input)
- Optimized for agentic workflows with configurable reasoning effort
- 64K output tokens enables substantial code or document generation
Caveats
- Smaller context window than GPT-5.2 (200K vs 400K)
- Adaptive reasoning in Instant tier may add unpredictable latency
- Thinking tier slower than standard models for simple queries
- Not ideal for tasks requiring maximum context (e.g., analyzing entire large codebases)
- Vendor
- OpenAI
- Context Window
- 200,000 tokens
- Max Output
- 64,000 tokens
- License
- Proprietary
- Release Date
- 2025-11-13
- Training Cutoff
- 2025-07-31
- Modalities
- textimageaudio
| Benchmark | Score |
|---|---|
| AIME 2025 | 89.0 |
| Codeforces | 88.0 |
Capabilities
Vision
Audio
Video
Tool Use
Resources
Pricing
$1.25 per 1M input tokens, $10.00 per 1M output tokens