# GPT-5.2-Codex

GPT-5.2-Codex is an AI model released by OpenAI on Dec 18 2025. It has a 400k context window. Tracked results include 45% on BullshitBench v2 and 46% on Next.js Evals.

## Facts

| Field | Value |
| --- | --- |
| Model | GPT-5.2-Codex |
| Developer | OpenAI |
| Release date | Thursday, Dec 18 2025 |
| Licensing | Closed |
| Context window | 400k |

## Tracked benchmark scores

| Benchmark | Score | Source | What it measures |
| --- | --- | --- | --- |
| BullshitBench v2 | 45% | [BullshitBench](https://github.com/petergpt/bullshit-benchmark) | Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. |
| Next.js Evals | 46% | [Next.js Evals](https://nextjs.org/evals) | Vercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. |

## About GPT-5.2-Codex

OpenAI introduced GPT-5.2-Codex on December 18, 2025 for software engineering in large repositories. OpenAI highlighted context compaction for long sessions, tool use and work in native Windows environments.

The first release reached paid ChatGPT users through Codex. OpenAI added Responses API access on January 14, 2026.

## Questions and answers

### When was GPT-5.2-Codex released?

GPT-5.2-Codex was released by OpenAI on Thursday, Dec 18 2025.

### Who made GPT-5.2-Codex?

GPT-5.2-Codex was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.

### What benchmark scores did GPT-5.2-Codex get?

GPT-5.2-Codex reports 2 tracked benchmark scores — BullshitBench v2: 45%; Next.js Evals: 46%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.

### What is the context window of GPT-5.2-Codex?

GPT-5.2-Codex has a context window of 400k. Providers may specify separate input and output token limits.

### Is GPT-5.2-Codex open source?

No. GPT-5.2-Codex is a closed model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

### What came before and after GPT-5.2-Codex?

OpenAI's previous tracked release was GPT-5.2 on Dec 11 2025, 7 days earlier. It was followed by GPT-5.3-Codex on Feb 5 2026.


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Canonical page: https://aireleasetracker.com/model/openai/gpt-5.2-codex
Site index: https://aireleasetracker.com/llms.txt
Source: AI Release Tracker (https://aireleasetracker.com). Most benchmark scores come from lab launch material; gathered results identify the leaderboard that published them.