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GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini is a smaller and faster version of GPT-5.1-Codex
11/13/2025
400,000 tokens
Specifications
Modalities
Input
image
text
Output
text
Supported Parameters
include_reasoning
max_tokens
reasoning
response_format
seed
structured_outputs
tool_choice
tools
Max Output Tokens
100,000Reasoning Configuration
- Default
- Thinking on (effort: medium)
- Selectable effort levels
- highmediumlow
- Turning thinking off
- Possible (reasoning.enabled: false)
Data policy
- Prompt retention
- Unknown — we could not confirm
- Training
- Unknown — not declared
"Unknown" does not mean "safe". It means we could not confirm it.
Whether a provider trains on prompts is a declared value from our terms with them. Retention is determined from the upstream listing for every host this model can reach. Neither is guessed.
Frequently asked questions
- Is GPT-5.1-Codex-Mini available on FastMetal?
- Not at the moment. GPT-6.1 Sol, from the same lab, is available on the FastMetal API today.
- What is the context window of GPT-5.1-Codex-Mini?
- 400,000 tokens, shared between the prompt and the response.