Kate's take, in a sentence or two

To transfer a custom GPT into Claude, Kate says you can't just download and re-upload it—instead, she opened Claude, turned on the Skill Creator feature, and pasted in her custom GPT's instructions, asking Claude to turn it into a skill, then uploaded any knowledge files afterward. She says the whole process took about five minutes and was very easy. However, she notes this only works for your own custom GPTs, since you'd need the backend access (custom instructions and knowledge files) that you don't have for someone else's GPT—which is also their IP.