As a rule, I commit the input to the code generation tool, i.e., what the GPL refers to as "the preferred form of the work for making modifications to it", generate as part of the build process, and, where possible, try to avoid code generation tools designed around the assumption that its output will be maintained rather than regenerated from modified input.

As for LLM code assistants, I don't really view them as traditional code generation tools in the first place, as in practice they more resemble something in between autocomplete and delegating to a junior programmer.

As for attribution, I view it more or less the same way as "dictated but not read" in written correspondance, i.e., an disclaimer for errors in the code, which may be considered rude in some contexts, and a perfectly acceptable and useful annotation in others.