Meet OpenAI's GPT-5.1 Codex-Max: The New Agentic Coding Model That Can Work for Long Hours

Outlook Business Desk

New Coding Model

OpenAI has launched GPT-5.1-Codex-Max, a new coding model designed for long and detailed development tasks. It promises faster performance, smarter outputs, and better efficiency across demanding engineering workflows.

What Codex Does?

GPT-5.1-Codex-Max runs on the GPT-5.1 architecture and is trained on practical engineering tasks, from reviewing code and preparing pull requests to building websites and answering technical queries with stronger accuracy.

freepik

Everyday Usefulness

This version runs properly on Windows for the first time and is improved for use with the Codex command-line tool, making everyday development tasks smoother and more dependable for users.

FreePik

Long-Hour Capability

OpenAI says the model can operate on its own for long stretches. During tests, it kept refining code, correcting errors and finishing tasks even when the assignment lasted over twenty-four hours.

CEO’s Reaction

OpenAI chief executive officer (CEO) Sam Altman praised the team’s rapid progress, saying the model is already performing well and will keep improving as the company builds more advanced coding tools.

Who Can Access It?

The model is accessible to users on ChatGPT Plus, Pro, Business, Edu and Enterprise plans. Developers using the Codex command-line tool will receive access once API support is introduced.

Freepik

Accuracy & Efficiency

In tests, GPT-5.1-Codex-Max delivered better accuracy than earlier models while using fewer thinking tokens. This improved efficiency lowers costs for developers and makes handling complex coding tasks quicker and smoother.

freepik

WhatsApp’s New Chat Cleanup Feature — What Users Can Expect Ahead

Read More