You are helping a person add Cofounder to ChatGPT on the web (chatgpt.com) as a custom MCP server. This happens entirely in ChatGPT’s web UI. Editing local MCP, Codex, or Claude configuration files does not connect ChatGPT on the web.
Walk the person through one step at a time, using the exact UI labels and values below, and wait for them to confirm each step before moving on. Tell them which step of this page matches, so they can follow along.
The person checks the risk acknowledgement, signs in to Cofounder, and clicks Allow access themselves. Never ask for passwords, API keys, tokens, or OAuth client secrets. No client ID or secret is needed: ChatGPT discovers OAuth settings from the server URL.
Clicking Next on this page is navigation, not proof of a connection. The connection is confirmed only when a Cofounder tool call succeeds in a ChatGPT chat with Cofounder selected.
If Cofounder tools are already available in the current chat, Cofounder is connected: skip this guide and continue onboarding instead of sending the person through it again.
Once connected, the person continues onboarding on the ChatGPT website, in a new chat with @Cofounder selected. Call onboarding_get first and follow its guidance; skip only the steps that need a local shell or filesystem.
Steps (this page shows one at a time at /setup/chatgpt?step=1 through 5)
Open ChatGPT Plugins. Sign in to chatgpt.com and open **Plugins** from the sidebar, or use the button below. Keep this tab open and come back after each step. Done when: You see the Plugins page with an **Add** button at the top right.
Add a custom MCP server. Click **Add** next to the search bar, then choose **Add custom MCP server**. Skip Create plugin and Upload plugin archive. Done when: The **Add custom MCP server** form is open.
Fill in Cofounder’s details. Copy each value into the matching field. Fields marked Default are already set, so leave them, along with **Advanced OAuth settings**. Done when: Server URL ends in /mcp and Authentication says **OAuth**.
Create the plugin and sign in. Check **I understand and want to continue**, then click **Create as a plugin**. When ChatGPT asks you to connect, sign in to Cofounder and click **Allow access**. Done when: Cofounder is listed under **Installed** in the Plugins sidebar.
Get started in a new chat. Start a new chat, type **@**, pick **Cofounder**, and send the message below. Done when: Cofounder replies and starts setting up your company with you. You’re connected.
Add custom MCP server form values
Icon (optional): PNG at /guides/cofounder-icon.png on this site
Name: Cofounder
Description (optional): Build and run your company
Connection: Server URL (already selected; leave it)
Server URL: https://api.superoptimizers.cofounder.co/mcp
Message to send in a new chat with @Cofounder selected
Help me get started with Cofounder.
Troubleshooting
I don’t see Add custom MCP server: Custom MCP servers depend on your ChatGPT plan and workspace settings, and a workspace admin may need to allow them. If the option isn’t there, set up Cofounder in the Codex or Claude desktop app instead.
Sign-in didn’t finish: Open Cofounder under Installed in ChatGPT Plugins and connect again with the same Cofounder account. Keep Authentication set to OAuth; the other options won’t fix a sign-in error.
Cofounder doesn’t show up after @: Start a brand-new chat and type @ again. Check that you’re in the same ChatGPT workspace where you created the plugin. Reconnect the existing plugin rather than creating a second one.
Custom MCP servers depend on your ChatGPT plan and workspace settings, and a workspace admin may need to allow them. If the option isn’t there, set up Cofounder in the Codex or Claude desktop app instead.
Sign-in didn’t finish
Open Cofounder under Installed in ChatGPT Plugins and connect again with the same Cofounder account. Keep Authentication set to OAuth; the other options won’t fix a sign-in error.
Cofounder doesn’t show up after @
Start a brand-new chat and type @ again. Check that you’re in the same ChatGPT workspace where you created the plugin. Reconnect the existing plugin rather than creating a second one.
Once Cofounder is connected, you can set up and run your company right from ChatGPT.