@benjamineskola That's the difficulty; it's one of those "I know it when I see it" situations.
I've seen clear LLM responses describing, for example, why a build fails or does something incorrectly included in PR descriptions, and those have been reasonable. Often the tools are better at citing locations for information than the average contributor which can make reviewing those contributions easier.
It's about the contributor understanding what they're doing, acting with intent, expecting accountability for the results even if an LLM they're using produced them, and having respect for maintainers' time.
Just pasting what a maintainer asks into the LLM and then uncritically pasting what the LLM says back is unacceptable.
Making what could be said in a 1 line PR message into paragraphs describing every individual semicolon in the change is unacceptable.
The contributor not having read their own submission is unacceptable.
Not disclosing which parts of a contribution are produced by an LLM is unacceptable.
But I don't think that makes all LLM generated content unacceptable. "I'm making this change because GPT 5.4 said <blah>" can be fine as long as <blah> is correct and not full of irrelevant garbage.