GPT-5.2 Codex

CodingClosed weightsTextReasoning

GPT Codex family model by OpenAI.

About the GPT Codex family

OpenAI's coding-specialized GPT-5-series models powering the Codex agent — optimized for repository-scale software engineering, debugging and long agentic coding sessions.

All GPT Codex models

How this one is configured

This configuration runs in reasoning mode (thinks step-by-step before answering).

Also runs at: xhigh effort

Effort controls how long the model thinks before answering — higher effort usually means better answers on hard problems, at the cost of speed and money. Same model underneath, so they share this page.

Who makes it

OpenAIUnited StatesMaker of ChatGPT and the GPT and o-series model families.