I had an idea at one point that I'd record every cover letter I wrote, so that eventually I could fine tune a model to write in my style.

I didn't end up sending many, but I've noticed that it's really difficult to get AI to write in a decent style. I've tried giving it a list of AI-isms to avoid, and it just doesn't work.

I has the most success with deepseek V3, giving a list of AI-isms, then ending with "You have been randomly assigned the following writing style/personality: [codeblock]" then a stereotype. Eg "Write in the style of a to-the-point, concise HN commenter" works alright, while "Write naturally and without AI-isms" is hopeless.

(Don't worry, I'm not using it for HN botting or whatever, it just tends to write in a nice style when you give it that)