If it's obviously AI generated and is an absurdly long PR, I'd ask them to extensively justify the complexity (especially if it does side quest-isms like this example where the AI created a DSL and stuff: why exactly is the DSL required?). If the project already implements the feature, I'd ask that they remove the re-implemented parts and use what already exists. If one of the dependencies of the project does this, I'd ask that they update the PR to use those instead of wholesale redoing it. If they respond, at all, with AI-generated responses instead of doing it themselves, or their PR description is AI generated, or it's blatantly obvious they used AI, I would immediately mentally classify the PR as an ultra low effort/quality PR until proven otherwise. Might seem harsh, but I prefer PRs from people who actually both understand the project and what the PR is trying to do. I don't mind if people use AI to assist in that understanding; I don't even mind if they use AI to help write parts of the PR. But if I can tell that it's AI generated (and completely re-implementing something that the project either has already or is in the stdlib or a dep is a very good sign of AI generated code in my experience), I'm far more inclined to dismiss it out of hand.