OpenAI Rolls Out GPT-5.1 Codex-Max, Suggesting Internal Naming Evolution for Coding Models

OpenAI has officially introduced GPT-5.1-Codex-Max, a new frontier agentic coding model, alongside a broader expansion of its GPT-5.1 family. This development follows observations from the AI community regarding internal naming conventions, with one user, Lisan al Gaib, noting on social media, "> Interestingly their system cards links to: https://t.co/KovZlfSKix GPT-5.1-Codex-Turbo instead of GPT-5.1-Codex-Max suggesting a last minute name change." This tweet highlights a potential evolution in the naming of OpenAI's specialized coding models.

GPT-5.1-Codex-Max is designed to be faster, more intelligent, and token-efficient for software engineering tasks, now serving as the default model in Codex surfaces. It is built for long-running, detailed work, capable of operating across multiple context windows through a process called compaction. This allows it to handle project-scale refactors and multi-hour agent loops, significantly enhancing developer productivity.

The introduction of Codex-Max is part of a wider GPT-5.1 upgrade, which also includes GPT-5.1 Instant and GPT-5.1 Thinking, aimed at general conversational and advanced reasoning tasks. These models are rolling out gradually to various ChatGPT users and will soon be available via API. The naming convention, including "Instant," "Thinking," "Pro," and "Reasoning," indicates OpenAI's strategy to offer specialized versions tailored for diverse user needs and applications.

The observation of "GPT-5.1-Codex-Turbo" in system card links, as noted in the tweet, suggests that "Codex-Max" might represent a refined or final public name for a model previously referred to as "Turbo" internally or in early stages. This practice of iterative development and potential internal naming shifts is common in rapidly evolving tech sectors. GitHub's changelog also confirms the public preview of GPT-5.1, GPT-5.1-Codex, and GPT-5.1-Codex-Mini for GitHub Copilot, further illustrating the breadth of the new model family.

These new GPT-5.1 models are available to various subscription tiers, including ChatGPT Plus, Pro, Business, Edu, and Enterprise plans. The focus on specialized coding capabilities with Codex-Max, alongside general-purpose and reasoning models, underscores OpenAI's commitment to delivering robust and versatile AI tools across different domains. The continuous refinement and expansion of the GPT-5.1 series are set to significantly impact the landscape of AI-powered development and interaction.