Your style is measurable. So we measure it.
Every question Timbrel asks is tied to a real body of research: stylometry, Biber's analysis of how language varies, the psycholinguistics of personality, and the mechanics of how models actually choose words. Here is the science, charted.
AI writing is average by design.
A model is trained to please the widest possible audience, then polished by raters who reward the safe and the fluent. So it slides toward the centre of everything it has ever read. One giveaway: humans are lumpy. Our sentence lengths swing; a model settles into one comfortable length and stays there.
Your fingerprint is made of small words.
The signal that gives a writer away doesn't live in the big content words. It lives in the glue you stopped noticing in second grade — the, of, that, while, upon, by. Stable across every subject you'll ever touch, as individual as handwriting.
In 1963, Mosteller and Wallace settled the disputed Federalist Papers with exactly this. Madison wrote whilst; Hamilton wrote while. Madison reached for upon far less often. Tiny unconscious habits, enough to assign all twelve papers with confidence that still holds.
A voiceprint is the Federalist method run backwards: measure a person, then project that fingerprint forward onto a model.
Biber found dials where everyone expected boxes.
In the late eighties the linguist Douglas Biber ran a mountain of text through factor analysis and found that features cluster into continuous dimensions. The sturdiest runs from involved (contractions, present tense, “you”) to informational (dense noun phrases, the writer stepping out of frame). A model already knows what every one of these means, so you can hand it your coordinates.
Personality leaves marks too. Lexical diversity, the ratio of adverbs to adjectives, how much you hedge. The Big Five traits show up as measurable habits. Timbrel maps all of it across thirteen dimensions.
The tells a voiceprint hunts down.
A model has a fingerprint of its own: habits it can't stop performing. Every voice file bans dozens of them by name, on by default, even in the free tier. These six are a sample, not the full list.
And your own genuine quirks? The phrases you honestly overuse are marked exempt, so they survive the cull — see it done on three real writers.
All of it, folded into one file.
A voiceprint is plain Markdown you paste into any model's system prompt. The order is deliberate: models pay most attention to the start and end of a prompt and lose the middle, so the hard rules are bracketed top and bottom. That same repetition is what keeps the voice from drifting as a long chat fills with noise.
The few-shot examples are the sample passages you picked as most like you. The model learns your voice by demonstration, never from prose you had to write. Ready-made context variants for email, blog and social ride along on Pro.
<you> — three exact adjectives. The non-negotiables, first.signature phrases marked exempt.How we know it’s yours.
