Unlocking the Codex harness: how we built the App Server

What is Codex?

Learn how Codex helps you go beyond chat by automating tasks, connecting tools, and producing real outputs like docs and dashboards.

Introducing upgrades to Codex

Codex just got faster, more reliable, and better at real-time collaboration and tackling tasks independently anywhere you develop—whether via the terminal, IDE, web, or even your phone.

Introducing Codex

Codex is now generally available

OpenAI Codex is now generally available with powerful new features for developers: a Slack integration, Codex SDK, and admin tools like usage dashboards and workspace management—making Codex easier to use and manage at scale.

Addendum to o3 and o4-mini system card: Codex

Codex is a cloud-based coding agent. Codex is powered by codex-1, a version of OpenAI o3 optimized for software engineering.

Running Codex safely at OpenAI

How OpenAI runs Codex securely with sandboxing, approvals, network policies, and agent-native telemetry to support safe and compliant coding agent adoption.

Working with Codex

Learn how to set up your Codex workspace, create threads and projects, manage files, and start completing tasks with step-by-step guidance.

Introducing the Codex app

Introducing the Codex app for macOS—a command center for AI coding and software development with multiple agents, parallel workflows, and long-running tasks.

Unrolling the Codex agent loop

A technical deep dive into the Codex agent loop, explaining how Codex CLI orchestrates models, tools, prompts, and performance using the Responses API.

Codex for (almost) everything

The updated Codex app for macOS and Windows adds computer use, in-app browsing, image generation, memory, and plugins to accelerate developer workflows.

Harness engineering: leveraging Codex in an agent-first world

By Ryan Lopopolo, Member of the Technical Staff

How to get started with Codex

Learn how to get started with Codex by setting up projects, creating threads, and completing your first tasks with step-by-step guidance.