---
title: Codex beside your AI: a second opinion, on your plan
description: Codex, OpenAI's coding AI, on your own ChatGPT plan: a session in your brain's folder, a task Claude Code hands it, images to a brief, a second opinion.
url: https://instibrain.ai/works-with/codex
updated: 2026-10-27
site: https://instibrain.ai/llms.txt
---

# A second AI, same folder, same brain.

OpenAI's coding AI on your ChatGPT plan, beside Claude Code. It reads the same brain through `AGENTS.md`.

What you can ask  →  Where the credential stays

your chatgpt plan · codex exec · AGENTS.md

`personal/tools/codex/codex.md` your plan, your setup
asked · an example Get a second read on the migration plan before I run it.
the AI, from the page GPT says the backfill must run before the constraint. I checked the schema: it is right, so I moved the step.
what instibrain heldThe plan, on its page. The answer changed it only after a check.

who uses it, and why

## Who calls in the second AI.

Two models, one brain, for work that needs a second look.

a reviewer

### A diff read twice before merge.

why One model can miss what another catches.

asks Have Codex review this diff, then check what it says.

a founder

### A cover image, drawn to your brand.

why The launch post needs an image today.

asks Draw a cover for the launch post from our brand page.

a developer

### A long task, in a window of its own.

why A long task would block your only session.

asks Open a Codex window for the test fixes.

what you can ask

## Your AI hands Codex a second read, an image, or a window of its own.

When your Claude limits run out, work goes on: same folder, same pages, another model.

Run a session

In your instibrain folder, reading the brain through `AGENTS.md`.

Take a task from Claude Code, with no window

`codex exec`, with the prompt before any image flag.

Draw images to a brief

Claude writes the brief from your pages. Codex draws it.

A second opinion

A GPT read on a plan, page or diff, then checked.

A window of its own

Its own title and background colour, beside the others.

where the credential stays

## Your ChatGPT plan is the sign-in.

Codex's limits are its plan's. Its sign-in is yours.

on your computer

Installed with brew or npm, signed in with ChatGPT. Every image is checked before anyone sees it. Logo and copy go on afterwards.

in your brain

A page names your plan and setup. The builder writes `AGENTS.md`.

what instibrain never touches

## Your AI checks every Codex answer before it acts on it.

Codex runs under your sign-in. Our server stores only your setup page.

-
Your OpenAI sign-in.

It stays on your computer. No page carries it.

-
An unchecked answer.

It changes a plan only after a check against the source.

-
Generated text or a logo in an image.

They come out wrong, so both go on afterwards.

the limits

## Codex stops where your ChatGPT plan's caps stop it.

Both come with your ChatGPT plan.

| Limit | What it means |
| Its limits are its plan's | GPT models, with your ChatGPT plan's caps. |
| An image costs about a minute and 30,000 tokens | Each one counts toward your plan's caps. |

before you connect it

## Codex reads your brain beside Claude Code, on your own plan.

**Is Codex part of instibrain?**

No. It is OpenAI's AI on your plan. You can also connect it over MCP.

**Which AI runs the tools?**

Claude Code runs them. Codex adds second reads, images and another model.

**Does Codex see a sealed space?**

On an admitted computer, as files. Over MCP, open spaces only.

## Claude Code and Codex work from one folder and one brain.

A second model starts from the same map on day one.

Request access  →  Connect Claude Code
code  Bitbucket

Repos, pull requests and code search, with your own token.
every kind  Works with

Every system by kind, and the rule each page shares.

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instibrain is made by WebWork AI, Inc. Everyone uses the same models · the difference is what yours knows.