GPT-5.1-Codex-Max

A coding-specialized model from OpenAI's GPT-5.1 generation with a 400k token context window, positioned between GPT-5.1-Codex-Mini and GPT-5.2-Codex in the lineup.

Strengths

Handles code generation, analysis, and debugging across large codebases and multi-file projects within its expanded context window.

Best for

Development workflows that need strong coding performance on complex programming tasks with access to substantial amounts of code context.

Limitations

Optimized for code work rather than general-purpose reasoning; newer GPT-5.2-Codex may offer improved performance on the same specialized tasks.