I Built a Native Codex Development Environment for Android

Pascal — Fri, 04 Sep 2026 16:35:50 +0000

Most AI coding workflows on mobile still assume one thing:

Somewhere, there is another computer doing the real work.

I wanted to see how far I could push the opposite idea.

What if the Android device itself hosted the workspace, terminal, development tools and Codex runtime?

That became AGENTCODI.

Codex workflows, directly on Android

AGENTCODI is an open-source Android application built around the Codex app-server.

The application interface is native Android, while the runtime, workspace and terminal run directly on the device.

There is no Termux requirement, no WebView shell and no separate gateway that has to be configured first.

You install the APK, authenticate with ChatGPT or an OpenAI API key, create a workspace and start working with Codex.

The AI model itself still runs online, of course. The important difference is where the development environment lives.

Your Android device is the machine Codex works on.

What actually runs on the device?

AGENTCODI currently includes:

Codex app-server
A private project workspace
An interactive terminal
Node.js and npm
Python
ripgrep
File importing and exporting
Workspace ZIP export
Native approval dialogs
MCP, tools, skills and app discovery
GitHub and Gmail integration through hosted Codex apps

You can follow commands, plans, reasoning summaries, file changes and tool activity directly inside the conversation.

The workspace can also be inspected manually at any time.

So if Codex changes ten files, you are not staring at a chat message hoping everything went well. You can open the workspace and see the result yourself.

Android changes the security model

Giving an autonomous coding tool filesystem access on a phone deserves some thought.

AGENTCODI therefore uses a private application workspace by default.

In Protected Mode, Codex operates inside that workspace and supported actions can require explicit approval.

There is also an experimental full-access compatibility mode for workflows that need fewer filesystem restrictions. Recent versions added optional approval handling there as well, so file and command changes can still require confirmation.

Imports and exports go through Android's document picker, keeping access explicit.

This is still Early Access

The current release is AGENTCODI 0.6.11 for ARM64 devices running Android 10 or newer.

The project is written primarily in Java and C++, and the packaged Codex app-server is currently version 0.148.1.

For the 0.6.11 release, the test suites completed with:

231 Java tests passed
297 C++ tests passed

The latest release also fixed Unicode backspace handling in the terminal and improved approval controls for the full-access workflow.

There is still plenty I want to improve. Android is a very different environment from a normal Linux workstation, and building a reliable coding-agent runtime there has produced some wonderfully strange problems.

That is also what makes the project interesting.

Why build this?

Phones and tablets have become extremely capable machines.

Yet most developer tooling still treats them as viewers, remote controls or emergency terminals.

AGENTCODI is an experiment in treating Android differently.

A device with its own workspace, runtime, terminal and coding agent can become an actual development environment you carry around.

And apparently I decided that getting Codex running natively on Android was a perfectly reasonable way to test that idea.

The project is open source under Apache 2.0.

GitHub: https://github.com/Mcpasi/AGENTCODI

Feedback, bug reports and contributions are welcome.

DEV Community: Pascal

I Built a Native Codex Development Environment for Android