It depends on what level of creative control you had over the code.

Code is protected by copyright as a literary work. The method is not protected by copyright, that would be the domain of patents. What's protected are the words.

If you say "Claude, build me a website about X" then you do not have any creative control over the literary work Claude is producing. You just told a machine to write it for you. Nor, like a compiler, is it derivative of any other work that you wrote.

If, on the other hand, you are working jointly with Claude to make specific changes to the code on a line-by-line basis, then you will have no problem claiming copyright over the code. Claude in this case is acting as a tool, but there's still a human making decisions about the code.

In the case where you wrote a bunch of markdown and then told Claude to generate the corresponding code but didn't have any involvement in writing the code itself, you could perhaps claim that the code is a derivative work of the markdown, a court would have to handle that case-by-case basis and evaluate how much control you exerted over the work.