Metadata
- Author: Simon Willison’s Weblog
- Full Title: GPT‑5-Codex and Upgrades to Codex
- URL: https://simonwillison.net/2025/Sep/15/gpt-5-codex/#atom-everything
Highlights
- GPT‑5-Codex and upgrades to Codex. OpenAI half-released a new model today: GPT‑5-Codex, a fine-tuned GPT-5 variant explicitly designed for their various AI-assisted programming tools. I say half-released because it’s not yet available via their API, but they “plan to make GPT‑5-Codex available in the API soon”. (View Highlight)
- I wrote about the confusing array of OpenAI products that share the name Codex a few months ago. This new model adds yet another, though at least “GPT-5-Codex” (using two hyphens) is unambiguous enough not to add to much more to the confusion. (View Highlight)
- I wrote about the confusing array of OpenAI products that share the name Codex a few months ago. This new model adds yet another, though at least “GPT-5-Codex” (using two hyphens) is unambiguous enough not to add to much more to the confusion. (View Highlight)
- At this point it’s best to think of Codex as OpenAI’s brand name for their coding family of models and tools. (View Highlight)
- At this point it’s best to think of Codex as OpenAI’s brand name for their coding family of models and tools. (View Highlight)