The problem

Newer AI models, like Claude 3.7 and especially Gemini 2.5 Pro, have an annoying tendency to over-comment their code. It doesn’t matter how fiercely you tell them not to do this. They simply love adding pointless comments:

if (whatever)
{
    // Exiting early because whatever was true.
    return;
}

The solution

The models won’t follow your instructions to stop leaving comments. But, I’ve found, they will follow your instructions to mark their comments.

In the CONVENTIONS.md file I use with aider, I have this line:

- Prefix all of your comments with 'AI:'. For example, '// AI: Added so we can access FooService.'

This works like a charm. The model will consistently include the 'AI' tag in its comments.

Then, it’s a simple case of using a regular expression to find and delete them.

Naturally, I used some other model to come up with this regex, but it works well:

\s*//\s*AI:.*\r?\n?