The OpenAI Developers plugin helps you build AI applications and agents in Codex with OpenAI Platform access and OpenAI API setup guidance. It works together with the OpenAI Docs Skill that comes bundled with your Codex install.
It includes:
- OpenAI API Platform: connect Codex to the OpenAI API Platform.
- API key setup: create, save, and connect a project API key from Codex when your app needs OpenAI API access.
- Agents SDK: build and deploy OpenAI Agents SDK apps from an idea, a repo, or a prior Codex thread.
- Troubleshooting: identify common OpenAI API failures and route you to the right next step.
For API key setup, the plugin creates new API keys in your Default Org under the Default project. You can set your default organization in your profile settings.
Get started with Codex
If you are new to Codex, start here before installing the plugin:
- Download the Codex app for macOS or Windows.
- Follow the Codex quickstart to sign in, choose a project, and send your first message.
Install the plugin
-
Open Codex
Start Codex from your terminal:
codex -
Open the plugin browser
Run:
/plugins -
Install the plugin
Search for OpenAI Developers, open it, and select
Install plugin. -
Complete any setup prompts
If Codex asks you to connect the bundled OpenAI Platform app, complete that setup so the plugin can create project API keys when needed.
-
Start a new thread
Open a new thread before using the plugin for the first time.
Use the plugin
After installation, start building with Codex! Codex can use the plugin automatically when the task calls for OpenAI Platform interactions, such as creating API keys, or troubleshooting API issues.
The plugin is useful when you want Codex to:
- build an app or agent that uses the OpenAI API
- create an OpenAI API key for the app you are building
- diagnose common OpenAI API errors and explain the next step.
Sample prompts
Build a new app
Build an app with the Responses API
Create a campaign studio that turns a brief into polished copy and generated visual directions.
Build an agent with the Agents SDK
Create a launch-planning agent with a frontend, useful tools, and observability hooks.
Build a realtime audio app
Make a voice-first worldbuilding companion with low-latency audio interactions.
Improve an existing app
Upgrade to the latest model
Create a no-code-change plan to modernize model/API usage while preserving behavior.
Optimize my API implementation
Create a no-code-change optimization plan for quality, latency, reliability, and cost.
Migrate from Responses API to Agents SDK
Create a no-code-change migration plan for whether and how to move to the Agents SDK.