The definition names the ingredients without explaining what they do for you. I’ve treated your comment as a request to replace that paragraph:

A personal benchmark helps you find which AI models do your work to your standards. Say you ask AI for feedback on an article opening. It praises the introduction, but you wanted it to notice that the headline buries the strongest claim and the first sentence is too vague. Save that article, your request, and what the feedback should have caught. Now give the same assignment to different models and see which ones catch those problems. Collect examples like this from your work, and you have a test you can use whenever a new model comes out: will it actually help you do your job better?