AI model · OpenAI
GPT-5.1-Codex-Max
Model ID: openai/gpt-5.1-codex-max
- Input
- $1.25 per 1M tokens
- Output
- $10 per 1M tokens
- Context
- 400K tokens at once
- Max output
- 128K tokens per reply
- Released
- 4 Dec 2025 OpenAI
What it can do
- YesReasoning
- YesTool calling
- YesImage input
- NoOpen weights
- NoFree to use
Takes text, image; gives text.
How its listing describes it
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...
Sources
- OpenAI: GPT-5.1-Codex-Max on OpenRouter — read 2 Oct 2026