Why does my GPT custom action using OAuth client credentials prompt for a sign in?

Explanation

Custom GPT Actions that use OAuth expect an interactive flow (i.e., the OAuth authorization code flow), which involves a user signing in. The OAuth support provided in the current flow is designed for per-user authentication, not for the client credentials (user-agnostic) flow.

What’s happening:

• When you configure OAuth for a GPT Action, ChatGPT displays a "Sign in" button and expects the user to authenticate interactively.
• The client credentials flow, by nature, is non-interactive (it’s meant for server-to-server communication and doesn’t require a user login), so it interrupts the expected flow in the ChatGPT UI.

Solution

At the moment, to integrate your external API with OAuth authentication in GPT Actions, you'll need to use the OAuth authorization code flow rather than the client credentials flow. Here’s what you can consider:

1. Switch the OAuth strategy:

   • Reconfigure your external API’s authentication to follow the authorization code flow.
   • In this flow, users click the "Sign in" button and are redirected to your OAuth provider’s login page. Once authenticated, the callback URL (provided by ChatGPT) handles the authorization code exchange.

2. Review your action configuration:

   • Ensure you’ve entered the OAuth client ID, client secret, authorization URL, token URL, and scope as per the documentation.
   • Verify that your callback URL is correctly set up on your OAuth provider’s side.

References

• The OpenAI documentation for GPT Actions explains that OAuth in this context involves a user-driven sign in process.
• The guidance for setting up OAuth clearly outlines the necessary steps (client ID, secret, authorization endpoint, token endpoint, and callback integration).

By following these adjustments, your assistant will be better aligned with the supported OAuth flow and should resolve the issue of being stuck on the sign in prompt.