GPT-5.1-codex-max
gpt-5.1-codex-max
OpenAI · chat · api · seen 10m ago
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Context
400K
Max output
128K
Input $/1M
$1.25
Output $/1M
$10.00
Modalities
text
Released
20 Nov 2025
AI summary
● machine-written
OpenAI releases GPT-5.1-Codex-Max for agentic coding tasks
GPT-5.1-Codex-Max is OpenAI's agentic coding model designed for long-running, high-context software development tasks. The model supports a 400K token context window and is available through API access. It was released on December 4, 2025.
What's new
- 400K token context window for extended code sessions
- Maximum output of 128,000 tokens
- Pricing at $1.25 per million input tokens and $10.00 per million output tokens
- Designed for agentic long-running software development workflows
Best for
Long-running software development tasksHigh-context coding applicationsAgentic coding workflows