GPT-5.2 Codex

Published

Dec 18, 2025

GPT-5.2 Codex is an AI model developed by OpenAI (United States), first published in December 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. Epoch AI rates the confidence of this record as likely.

Full record

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

Benchmark results

01	WebDev Arena	Arena Score	1334.6
02	ALE Bench	Performance	1299.9
03	Terminal-Bench	Accuracy mean	0.67
04	Apex Agents	Pass@1 score	0.28
05	Posttrainbench	Average (%)	0.17