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openaiOpenAI: GPT-5.1-Codex-Max
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...
openai/gpt-5.1-codex-max
Context Size
400K
Input Price
187,500 pts/M
Output Price
1,500,000 pts/M
Architecture
Text
Image
Supported Parameters
include_reasoningmax_completion_tokensmax_tokensreasoningresponse_formatseedstructured_outputstool_choicetools
Details
TokenizerGPT
Max Completion128,000 tokens
Provider Context400K tokens
ModeratedYes
CreatedDec 4, 2025