GPT-5.2 Codex

• 🔧 Coding-specialized variant built on OpenAI's GPT-5.2 base model.
• 🧠 Tuned for long-horizon, agentic software engineering tasks.
• 📏 256K context, extended further via native context compaction.
• 🔒 Notably stronger defensive cybersecurity capabilities than prior Codex models.
• 🆕 Improved large refactors, code migrations, and Windows-environment reliability.
• 👁️ Supports reasoning, vision, function calling, and web search.
• ⚡ Offers low, medium, high, and xhigh reasoning-effort settings.
• 🏢 Geared toward professional, multi-hour repository-scale engineering work.

OpenAI

OpenAI is an American artificial intelligence research organization headquartered in San Francisco, structured as both a for-profit public benefit corporation and a nonprofit foundation. The lab developed the GPT family of large language models, the DALL-E…

GPT-5.2 Codex is OpenAI's coding-specialized model, an edition of GPT-5.2 further optimized for agentic software engineering inside the Codex platform. Released in 2025, it is built to handle long-horizon work: large-scale code transformations, refactors, migrations, and feature builds that span extended sessions. It supports four reasoning-effort levels (low, medium, high, and xhigh) and exposes reasoning, vision, function-calling, and web-search capabilities.

Compared with earlier Codex models such as GPT-5.1-Codex-Max, OpenAI reports improvements in long-context understanding, more reliable tool calling, improved factuality, and native compaction—the ability to compress history and keep working coherently past the base context window. This lets it operate in large repositories over extended sessions without losing track, even when plans change or attempts fail. OpenAI also highlights stronger performance in native Windows environments and significantly enhanced cybersecurity capabilities, calling it the strongest model on its internal Professional CTFs evaluation to date, aided by compaction on long-running cyber tasks.

OpenAI evaluates the model on SWE-Bench Pro, where it must generate a patch to solve realistic software engineering tasks, though specific figures should be confirmed against the official model card and addendum.

Within the Codex lineage, GPT-5.2 Codex was succeeded by GPT-5.3 Codex, which OpenAI describes as combining the Codex training stack with GPT-5's reasoning and general-intelligence stack.