GPT assistant learning from my github repo of sample code?

I want to build a GPT to write code according to a set of sample code with specific syntax. I can feed content of individual sample files and get some good results, but I wonder if I can give it a link to my github repo, and ask it to read all sample files in the repo, and so I won’t have to manually feed individual file content.

It appears that it does not do anything when instructed to read files from an HTTP URL, and when asked to confirm about the specified code repo, it always tells me that it cannot make the HTTP connection at the moment. Does it mean that it cannot read multiple files from HTTP connection, or I have to feed individual files one at a time?