Use OpenSEO with ChatGPT

The custom OpenSEO connection in this guide works on ChatGPT Free and paid plans. You do not need to upgrade. On Business, Enterprise, and Edu, workspace permissions can limit access.

Connect OpenSEO before asking ChatGPT to do SEO research. If you paste the setup prompt into a regular ChatGPT chat, it will walk you through the steps below; ChatGPT cannot add the connection by itself.

Choose your setup path

Where you want to work	How to connect
ChatGPT on the web	Add OpenSEO as a custom MCP connection using the steps below
Codex in the ChatGPT desktop app	Open Codex and paste the agent setup prompt

OpenSEO billing is separate from your ChatGPT subscription. See OpenAI's plan support for Codex access.

ChatGPT on the web

Sign in to chatgpt.com.
If your version shows it, open Settings → Security and login and enable Developer mode. Some versions expose the custom connection flow directly in Plugins.
Open Plugins, select +, then Create MCP App. In versions with the older interface, look for Settings → Apps → Advanced settings → Developer mode, then Create or Add custom app.
Enter these details:

Field Value
Name OpenSEO
Server URL https://app.openseo.so/mcp
Authentication OAuth

Type the full URL, including https://. These settings apply to hosted OpenSEO. For a self-hosted instance, use a publicly reachable HTTPS endpoint with authentication supported by ChatGPT; localhost URLs cannot work from ChatGPT web. Follow the self-hosting guide or use a local Codex connection instead. The official directory plugin targets hosted OpenSEO.
Review the custom connection notice and create the connection. Sign in to OpenSEO in the window that opens and approve the connection. Return to ChatGPT. If the new plugin needs installation, open it under Personal and select Install or +.
Start a new chat. Open the + / tools menu and select OpenSEO. In versions that show Developer mode in that menu, choose it and enable OpenSEO there. If the composer offers plugin mentions, you can also type @ and select OpenSEO.
Send the connection-check request below.

Field	Value
Name	`OpenSEO`
Server URL	`https://app.openseo.so/mcp`
Authentication	`OAuth`

Use OAuth for this flow. You do not need to create an OpenSEO API key or paste one into ChatGPT. A custom MCP connection gives ChatGPT OpenSEO tools; it does not install the SEO skill files from the repository. You can still ask for keyword research, audits, or competitor research in plain language.

See OpenAI's connection guide for its current interface.

ChatGPT desktop

If you already use Codex in the desktop app, start a new Codex chat, then copy the agent setup prompt into that chat. Codex can configure its own connection and guide you through sign-in. Approve the OpenSEO login when prompted.

If you prefer manual setup, follow the Codex plugin guide, or add the MCP connection alone. Start a new Codex chat after installation if needed, then run the connection check below.

For a regular ChatGPT chat in the desktop app, check Plugins. If OpenSEO is listed for your account, install it, sign in, start a new chat, and select OpenSEO. If it isn't available, follow the web setup steps above.

Codex and ChatGPT web use separate connections. Run the connection check in the chat where you want to use OpenSEO.

For the current mode controls, see OpenAI's desktop guide.

Check that OpenSEO is connected

Send this in a new chat with OpenSEO selected:

Use OpenSEO to check my connection and list my projects. Do not run SEO research or create anything.

ChatGPT should call OpenSEO and return your connection status and project list. An empty project list is a successful connection check too. These reads use no OpenSEO credits.

If it says it cannot access OpenSEO, or only describes how to connect, setup is still incomplete. Check that OpenSEO is installed, signed in, and selected in this chat. Start a new chat after changing the connection.

Once the check succeeds, try:

Use OpenSEO to help me choose one SEO task for my website. Ask about my goal before starting paid research.

Directory plugins may also include SEO Coach and other skills. Use the available skill picker or ask for a workflow by name. A custom MCP connection can use the tools without those skills.

Troubleshooting

What you see	What to do
No Developer mode or Create MCP App option	Check Settings → Security and login and Settings → Plugins → Developer mode. On a workspace plan, ask your admin whether custom connections are allowed.
"Error fetching OAuth configuration: Unsafe URL"	Enter the server URL in full as `https://app.openseo.so/mcp`, with no spaces. A URL without `https://` is rejected.
No OpenSEO listing	A GitHub marketplace plugin is not automatically a public ChatGPT listing. Use the custom web connection or the Codex repository plugin steps.
ChatGPT asks for a client ID or secret	Keep OAuth selected and wait for discovery. Open Advanced OAuth settings and use Dynamic Client Registration (DCR) if offered. You should not need to supply your own client credentials for hosted OpenSEO.
The login window never appears	Allow the sign-in window to open, then retry authentication from the OpenSEO connection's details.
Login succeeds but tools are unavailable	Finish installing the personal plugin if prompted, start a new chat, and select OpenSEO from the tools menu.
ChatGPT gives general advice instead of calling OpenSEO	Select OpenSEO and resend the connection-check request. Check that ChatGPT calls an OpenSEO tool.
Codex works, but chatgpt.com cannot find OpenSEO	Connect ChatGPT web separately. It does not read your desktop Codex configuration.
You have no projects	An empty project list still confirms the connection. Create a project in OpenSEO when you are ready to start research.

If setup still fails, contact support@openseo.so with your ChatGPT plan, web or desktop version, the step that failed, and the error message. Do not include passwords, API keys, or sign-in codes.

Update OpenSEO

For a public directory plugin, start a new chat to load the tools and skills available in ChatGPT. Reconnect if ChatGPT reports that sign-in needs attention. Local Codex update commands do not update ChatGPT web.

For a custom MCP connection, open its details under Plugins, select Refresh to reload the tools, and start a new chat. Refresh updates tool definitions; it does not add repository skills. If sign-in has expired, authenticate again.

For Codex, use the agent update prompt or plugin commands in your Codex environment.