GPT-5.1-Codex-Max

Published

Nov 19, 2025

GPT-5.1-Codex-Max is an AI model developed by OpenAI (United States), first published in November 2025. It works in the language domain, on tasks such as language modeling/generation.

Epoch AI has no training-compute estimate for this model.

Access: API access. Its weights are not openly released.

Full record

Organization: OpenAI
Country of organization: United States
Domain: Language
Task: Language modeling/generation
Model accessibility: API access
Open weights: No

Benchmark results

01	ALE Bench	Performance	1208.8
02	METR Time Horizons	average_score	0.72
03	Terminal-Bench	Accuracy mean	0.6
04	Posttrainbench	Average (%)	0.2
05	Proofbench	Accuracy	0.09