I googled for inspiration. They are for a character which should provide information but only tells you strange things.
Easy. Look up something on the internet and imagine a character just did it. On a timescale from 0 to infinity, how long the character forgets about it without a priming conversation starter determines how sane they are.
Infinity = perfect sanity, almost machine-like.
A score of less than infinity appears to be OCD. Probably normal.
Lasting only a few seconds makes someone incredibly annoying.
Bonus for innate randomness: Omitting info. Laughing at ridiculous statements, despite helplessly parroting them. Getting facts wrong: changing facts, imagining unknown information. Saying things out loud they meant to think, and not knowing.
