GPT-5.1 Codex Max
GPTSpecialized
ThinkingTool UseVisionStructured Output
About this model
GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic workflows spanning software engineering, mathematics, and research. GPT-5.1-Codex-Max delivers faster performance, improved reasoning, and higher token efficiency across the development lifecycle.
Performance Tier
Specialized
GPT-5.1 Codex Max is a specialized model from GPT : built for a specific domain.
Domain-specific model. Optimized for a particular task such as code generation, image creation, or web search.
Pricing
This model is included in Elosia plans| Type | per 1M tokens |
|---|---|
| Input (prompt) | $1.25 |
| Output (completion) | $10.00 |
| Cache read | $0.125 |
Capabilities
Context Length400K
Max Output Tokens128K
TokenizerGPT
Inputtext, image
Outputtext
Release DateDecember 4, 2025
Benchmarks
Programming
HumanEval
96%
SWE-bench Verified
75.8%
Recommended Use Cases
Coding
Strengths
- Extended compute for complex coding tasks
- High-accuracy multi-file code generation
- Deep repository understanding for large codebases
Limitations
- Significantly higher cost due to extended compute
- Slower response time — optimized for quality over speed
Resources
This model may use your data for training