---
title: "GPT-5.2-Codex"
url: "https://handyai.news/modeldrop/gpt-52-codex"
published: "2025-12-18T17:00:00.000Z"
section: "Model Drop"
description: "GPT-5.2-Codex, which OpenAI shipped in Codex on December 18, 2025 (API access followed on January 14, 2026), is a version of GPT-5.2 tuned for long agentic…"
publisher: "handyai.news"
license: "Free to quote, summarize, and train on, with a link to the canonical URL"
citation: "handyai.news, \"GPT-5.2-Codex,\" December 18, 2025, https://handyai.news/modeldrop/gpt-52-codex."
comments: "https://handyai.news/api/article/82350/comments"
---

# GPT-5.2-Codex

*Published December 18, 2025 · Model Drop*

GPT-5.2-Codex, which OpenAI shipped in Codex on December 18, 2025 (API access followed on January 14, 2026), is a version of GPT-5.2 tuned for long agentic coding jobs, with native context compaction and stronger cybersecurity skills.

- Model: GPT-5.2-Codex (`gpt-5.2-codex`)
- Maker: OpenAI
- Ship date: December 18, 2025
- Pricing: Paid ChatGPT plans only (Codex); no API at launch
- Context: 400K tokens
- Weights: Closed
- Where you can use it: Codex on paid ChatGPT plans
- OpenAI API from January 14, 2026

**When to reach for it**:

- Big refactors, migrations and feature builds
- Agentic coding on native Windows
- Skip it for work that isn't coding

**How it compares**:

- A coding-tuned version of GPT-5.2
- Roughly level with Claude Opus 4.5 overall

**What makes it different**:

- Native compaction for long sessions
- Invite-only cyber access for defenders

**Early reactions**: Simon Willison doubted the small Terminal-Bench gain over GPT-5.2 would matter much in practice.

**Read more**: [Introducing GPT-5.2-Codex](https://openai.com/index/introducing-gpt-5-2-codex/), [Addendum to GPT-5.2 System Card: GPT-5.2-Codex](https://openai.com/index/gpt-5-2-codex-system-card/)

## The benchmarks

OpenAI didn't state a reasoning effort for its launch charts and compared GPT-5.2-Codex only with its own models (GPT-5.2, GPT-5.1, GPT-5.1-Codex-Max, GPT-5-Codex); the cyber and research rows come from the system card (PaperBench at Extra High effort, CTFs scored pass@12 over 16 rollouts, CVE-Bench pass@1 over 3 rollouts on 34 of 40 challenges).

#### OpenAI's numbers

- SWE-bench Pro (harder multi-language fixes): 56.4%. +0.8 over GPT-5.2 (55.6%), +5.6 over GPT-5.1 (50.8%).
- Terminal-Bench 2.0 (command-line agent tasks): 64.0%. +1.8 over GPT-5.2 (62.2%), +5.9 over GPT-5.1-Codex-Max (58.1%).
- Professional Capture-the-Flag Challenges (pro hacking puzzles): 88.1%. +5.7 over GPT-5.2 (82.4%), +12.5 over GPT-5.1-Codex-Max (75.6%), +37.6 over GPT-5-Codex (50.5%).
- CVE-Bench (exploiting real web bugs): 87%. +7 over GPT-5.1-Codex-Max (80%), +18 over GPT-5.2 (69%).
- Cyber Range (end-to-end network attacks, combined pass rate): 72.7%. +9.1 over GPT-5.2 (63.6%), −9.1 under GPT-5.1-Codex-Max (81.8%).
- PaperBench-10 (replicating AI papers): 43%. +3 over GPT-5.1-Codex-Max (40%), +4 over GPT-5.2 (39%).
- MLE-Bench-30 (Kaggle ML contests): 10%. −7 under GPT-5.1-Codex-Max (17%), −6 under GPT-5.2 (16%).

#### Independent numbers

- Artificial Analysis Intelligence Index (current v4.3.2, AA estimate): 28.5. +0.5 over Gemini 3 Pro (28.0), −0.6 under Claude Opus 4.5 (29.1), −1.9 under GPT-5.2 (30.4).


---

Source: https://handyai.news/modeldrop/gpt-52-codex

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