Codex
Codex is OpenAI’s terminal coding agent. In Frontend it runs on the server runtime, so it’s available on the Plus plan.
Start Codex
Section titled “Start Codex”On a project using the server runtime, click Codex in the sidebar’s Agents group. It opens in the left panel with the project as its working directory.
Sign in
Section titled “Sign in”The first time, Codex asks how to sign in:
- Sign in with ChatGPT — use your ChatGPT plan. Codex is included with ChatGPT Free, Go, Plus, Pro, Business, Edu and Enterprise, with higher limits on paid plans.
- API key — pay per token at OpenAI API rates with a key from your OpenAI Platform account.
Frontend saves your Codex login, encrypted, to your Frontend account, so Codex is signed in on your other projects.
| Link | |
|---|---|
| Codex pricing and plan limits | learn.chatgpt.com/docs/pricing |
| Compare ChatGPT plans | chatgpt.com/pricing |
| Create an API key | platform.openai.com/api-keys |
What’s set up for you
Section titled “What’s set up for you”- MCP servers. The project’s MCP servers are written to Codex’s
config.tomlbefore it starts, so it can use the project’s database, media, image generation and connected integrations. - A Linux machine. Codex runs on the project’s 2 vCPU / 4 GB server, so it can install system packages and run anything the project needs.
Project instructions
Section titled “Project instructions”Codex reads AGENTS.md files in the project for instructions such as commands to run, code style and conventions. See agents.md.