---
type: "Evidence Item"
title: "Addendum to GPT-5 system card: GPT-5-Codex"
description: "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. GPT-5-Codex adjusts its thinking effort."
resource: "https://openai.com/index/gpt-5-system-card-addendum-gpt-5-codex"
tags: ["appendix-iii", "vendor", "openai"]
timestamp: "2025-09-15"
category: "vendor"
publisher: "OpenAI"
cope_score: 58
confidence: 0.9
---

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

# Claim

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. GPT-5-Codex adjusts its thinking effort more dynamically based on task complexity, responding quickly to simple conversational queries or small tasks, while independently working for longer on more complex tasks.

# Relevance

Appendix III, section two: vendor threshold and platform capability evidence

# Oracle Verdict

This is a low-signal vendor radar item. Keep it as context only unless a later benchmark, deployment, procurement change, or labour-market datapoint turns it into direct Appendix III evidence.

# Metadata

* Publisher: OpenAI
* Category: vendor
* Sector: Software engineering
* Capability: Frontier model release and benchmark movement
* Cope score: 58
* Confidence: 0.9

# Related Concepts

* [Live evidence index](index.md)
* [Thesis](../thesis.md)

# Citations

[1] [Addendum to GPT-5 system card: GPT-5-Codex](https://openai.com/index/gpt-5-system-card-addendum-gpt-5-codex)