You're adding a connection to In Parallel, not building a new app. ChatGPT calls this connection an MCP app, so you may see Create app or Create MCP App during setup. You only need to enter the In Parallel details below. For the current web steps and account requirements, see OpenAI's guide to Developer mode and MCP apps.
Check access. Full MCP support, including write actions, currently requires ChatGPT Business, Enterprise, or Edu. A Business admin or owner can add the connection; Enterprise and Edu admins can also grant developer access. ChatGPT Pro supports read and fetch actions only. If someone adds the connection for your workspace, an admin or owner must publish its draft and grant you access before you can use it.
Add In Parallel. Choose the option to create an app, then enter In Parallel as the name,
https://www.in-parallel.ai/mcpas the server URL, and OAuth as the authentication method. Follow any tool-scan or safety prompts shown in your ChatGPT account.Authorize your In Parallel account. Sign in, then choose Full access for all current and future Workspaces or select individual Workspaces. Review the requested access and select Allow access. In a new ChatGPT chat, select In Parallel and ask about a Workspace you allowed.
Using the new ChatGPT desktop app? Go to Customize → Plugins → Add → Create MCP App. The screenshots below show the new desktop app, not ChatGPT Classic. They show a direct path to the connection form, without a separate Developer mode step in those menus.
OpenAI's current guidance still lists Developer mode and workspace permissions for custom MCP apps, and documents full MCP use on the web. If the desktop flow isn't available to you, complete and verify the connection in ChatGPT on the web.