GPT-5.1 codex

A version of GPT-5.1 optimized for agentic coding tasks.

Model Specifications

Context window 400,000 tokens
Max output 128,000 tokens
Knowledge cutoff September 2024
Multipart messages Yes
Vision capabilities Yes

Default Parameters

Temperature 0.3
Top P 1.0
Frequency penalty 0.0
Presence penalty 0.0

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