GPT-5.1 Codex Max
GPT-5.1 Codex Max is the maximum-context variant of GPT-5.1 Codex, built for analyzing and working with large codebases. Its extended context window allows it to understand entire repositories, making it ideal for large-scale refactoring, migration, and architectural analysis.
Max excels where other code models struggle — understanding cross-file dependencies, architectural patterns, and system-wide implications of changes.
Key Features
256K token context for full codebase analysis
Cross-file dependency understanding
Architectural pattern recognition
Large-scale refactoring and migration support
System-wide impact analysis
Ideal Use Cases
Large codebase migration and modernization
Architectural analysis and documentation
Cross-file refactoring at scale
Legacy system understanding and documentation
Example Prompts for GPT-5.1 Codex Max
Technical Specifications
| Context Window | 256K tokens |
| Modality | Text, Code → Text, Code |
| Provider | OpenAI |
| Category | Code Generation |
| Max Output | 64K tokens |
| Best For | Large codebase analysis |
Frequently Asked Questions
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