# OpenAI — Addendum to GPT-5 system card: GPT-5-Codex

- Company: OpenAI (openai.com)
- Announced: 2025-09-15T00:00:00+00:00
- Category: new-model
- Subject: GPT / ChatGPT / API
- Models affected: GPT-5-Codex
- Source: https://openai.com/index/gpt-5-system-card-addendum-gpt-5-codex
- Record: https://forck.live/items/472-addendum-to-gpt-5-system-card-gpt-5-codex

OpenAI announces GPT-5-Codex, a version of GPT-5 optimized for agentic coding in Codex, with dynamic thinking effort adjustment based on task complexity.

## Evidence

Verbatim from https://openai.com/index/gpt-5-system-card-addendum-gpt-5-codex:

> This addendum to the GPT-5 system card shares a new model: GPT-5-Codex, a version of GPT-5 further optimized for agentic coding in Codex.

---

Record: https://forck.live/items/472-addendum-to-gpt-5-system-card-gpt-5-codex
Catalogue: https://forck.live/llms.txt
Feed: https://forck.live/feed.md