Codex Finally Goes Mobile As OpenAI Expands AI Coding Agent To ChatGPT App

The competition among AI companies, often referred to as the LLM war, intensifies to productivity.

The launch of ChatGPT by OpenAI in 2022 marked the beginning of an intense period of competition in large language models. Within months, the tool gained over 100 million users and demonstrated the broad appeal of conversational AI. This prompted rapid responses from other technology companies. Google introduced its Bard model, later rebranded as Gemini. Anthropic released Claude, while Meta made its LLaMA models open source. Microsoft integrated advanced AI into its products, xAI launched Grok, and more that followed.

By 2024 and 2025, the focus shifted toward reasoning capabilities, with OpenAI advancing models like the o series that emphasized step by step problem solving. The competition extended to specialized applications, including software development tools.

OpenAI first introduced Codex in 2021 as a specialized model trained on code to generate programming snippets from natural language descriptions. It powered early versions of GitHub Copilot and demonstrated the potential for AI in software development.

However, OpenAI deprecated the original Codex models in its API. Newer general purpose models such as the GPT 4 had surpassed it in coding tasks, leading developers to migrate to those alternatives. The name Codex went on hiatus for roughly two years while broader model capabilities caught up.

Codex reemerged in May 2025 not as a simple code completion tool but as an autonomous coding agent.

This version functions as a software engineering teammate capable of handling complex tasks across codebases, including writing features, fixing bugs, and managing workflows in local or remote environments.

It operates through a dedicated desktop app, command line interface, and integrations, allowing it to run independently while providing updates and seeking approvals. Over the following year, Codex gained features such as background computer use, parallel agent execution, and support for hooks that customize its behavior with scripts for validation, logging, or repository specific rules.

In other words, OpenAI transformed Codex into a command center for building with agents.

Now, OpenAI announced an update that extends Codex access through the ChatGPT mobile application on iOS and Android.

Users can now connect their phones to instances of Codex running on laptops, Mac minis, or development boxes.

From the mobile app, it becomes possible to initiate new tasks, review outputs such as code changes or test results, steer ongoing execution, and approve subsequent steps.

The actual computation remains on the connected machine, with the phone serving as a remote interface that syncs real time information including screenshots, terminal outputs, and file diffs via a secure relay system. The feature rolled out in preview across all supported regions and all ChatGPT plans, including free tiers. Support for connecting to Codex apps on Windows is scheduled for a future release.

This development builds on earlier capabilities such as general availability of remote SSH connections for managed environments and programmatic access tokens for scoped credentials on business and enterprise plans.

For eligible ChatGPT Enterprise workspaces, Codex also supports HIPAA compliant use in local setups.

The mobile integration allows developers to monitor and direct long running tasks without remaining tied to a desk, while files, credentials, and project context stay on the host machine.

Reactions on social platforms reflected mixed views. Some users welcomed the ability to manage coding agents on the go, sharing screenshots of task lists and live updates.

Others noted that the announcement coincided with ongoing requests for other model improvements, such as restoring access to certain GPT variants. The update positions Codex as a more flexible part of the broader AI coding ecosystem that has evolved since its initial 2021 release and 2023 deprecation.

Rivals like Anthropic, launched Remote Control for Claude Code in February 2026.

This feature, similar to this Codex feature, allows users to run a local Claude Code agent session on their machine and control it remotely from the Claude mobile app or web interface.