https://mcp.nanocorp.so, and OAuth sign-in.
ChatGPT lets a custom app take actions, such as starting a business or
messaging it, on ChatGPT Business, Enterprise and Edu, on the web. On
ChatGPT Pro, a custom app can only read. Custom apps are not available in
the ChatGPT phone apps. This is ChatGPT’s own rule; see
OpenAI’s help.
1
Turn on developer mode
In ChatGPT, open Settings → Apps → Advanced settings and turn on
Developer mode. On Business, only admins and owners can turn it on. On
Enterprise and Edu, an admin gives you access first.
2
Create the NanoCorp app
In Settings → Apps, click Create. Name it If it shows client ID and client secret fields, leave them empty. Then
click Scan Tools.
NanoCorp, enter this
MCP server URL and choose OAuth for authentication:3
Sign in and allow
ChatGPT opens the NanoCorp sign-in page. Sign in, or create your account
there. The confirmation page names ChatGPT by its address,
https://chatgpt.com, and shows Not verified by NanoCorp. Check that
it sends your access to https://chatgpt.com and that the account is
yours, then click Allow.Back in ChatGPT, wait for the tool scan to finish, then click Create.4
Use it in a chat
NanoCorp appears under Settings → Apps → Enabled Apps, marked
Dev. In a new chat, select NanoCorp from the tools menu, or mention it
in your message. ChatGPT may ask you to confirm an action before it runs.