# Sign in with ChatGPT

> Use the Codex (ChatGPT) provider, understand limits, and reconnect after moving Macs.

The **Codex (ChatGPT)** connection uses your ChatGPT account for models available to your plan. It is separate from the installed Codex CLI provider and from an ACP Codex agent. You do not need an API key or a `codex` binary for this connection.

## Connect your account

1. Open **Settings → AI → Providers**.
2. Use **+** and choose **Codex (ChatGPT)**.
3. Press **Continue with ChatGPT** and complete the browser sign-in.
4. Return to Redcast and choose a model from the connection's catalog.
5. Send a message to confirm the account can use the selected model.

The browser returns to a temporary local listener on `127.0.0.1:4965`. It exists only during sign-in and closes on success, cancellation or timeout. If the callback fails, cancel the attempt, check that the port is available, and start again.

## Where it works

Its models appear in Quick AI, AI Chat, native agents, Quick Actions and extension AI wherever API connections are offered. Available models and reasoning levels come from the account's returned catalog; use **Refresh Models** to reload it.

Creativity is disabled for this route because it does not accept a temperature. Model capabilities still determine which attachments and tools are supported.

## Usage limits

The Providers panel and AI Usage show the most recent limit information received with your replies, along with its age. Redcast does not poll for fresh limits. **No limits yet** means no snapshot was received; it does not mean unlimited usage.

If a plan limit is reached, wait for its reset or deliberately select another connection. Redcast does not turn a ChatGPT request into a billed API request on its own.

## Credentials and backups

The connection's tokens live in the Mac's login Keychain. Redcast does not borrow `~/.codex/auth.json` for this route. Token refresh happens when a request needs it.

A backup can carry the connection entry, but **never its ChatGPT tokens or registration**, even with encrypted secrets included. After importing on another Mac, open the connection and sign in there.

**Sign Out** clears the local tokens and attempts remote revocation. If revocation cannot be confirmed, Redcast reports that and points you to ChatGPT settings. Removing the connection also removes its saved limit snapshot.

## Recovering a connection

- If authorization is denied, start a new sign-in and check the account you selected.
- If the connection says plan usage is not allowed, the account did not grant the necessary access.
- If refresh credentials are rejected, sign in again. A temporary network failure alone should not erase the saved login.
- If the catalog changes, refresh it and choose a currently available model.

This page describes the connection implemented by Redcast. Account eligibility, model access and plan limits are controlled by the provider and can change independently of the app.