Get the URL at which the plugin is hosted either by pressing the copy button, or by running:
In[6]:=
server["URL"]
Out[6]=
localhost:61003
Open the ChatGPT website in a browser. (There are some known issues with Safari.)
Select the Plugins model from the dropdown menu:
Then go to the Plugin store:
Press "Develop your own plugin":
Input the path to the local web server. The domain is always localhost, while the port is randomized by default. However, different ports can be selected in