Every: How to build an AI style guide

Katie Parrott’s guide draws on a historical observation: style guides have always emerged when technology changed how writing was produced. Hart’s Rules standardized output across Oxford’s compositors in 1893. The AP Stylebook adapted journalism for the constraints of the telegraph. Web writing guides addressed how text reads on a screen. The argument in this piece is that AI-assisted writing creates the same conditions again: a new production layer is in place, and it needs guidance to produce consistent, recognizable output.

The core problem is that language models converge on generic prose when left without direction. The patterns they default to—sentence structure, word choice, paragraph rhythm—reflect the statistical center of a very large training corpus, which tends toward interchangeable, impersonal text. A style guide fed into a model session describes the specific departures from that center that define a particular writer’s voice.

The practical steps Parrott describes involve surfacing patterns that writers often cannot articulate without prompting. She used ChatGPT to analyze a body of her own work and found structural preferences she had not consciously recognized—tendencies in how she opened paragraphs, how she handled transitions, how short her sentences ran in high-stakes moments. These patterns, once named, could be written down and included in a Claude project or system prompt.

The article notes an unexpected benefit: the exercise of building the guide was instructive independent of its AI use. Articulating why you write as you do—identifying the reasoning behind stylistic choices rather than just describing them—produces a document as useful for editing your own drafts as for guiding a model.

Parrott’s guide includes a template structure covering sentence-level patterns, tonal markers, structural habits, and words or constructions to avoid. She also addresses what a style guide cannot do: it cannot substitute for source knowledge, firsthand experience, or the judgment that comes from genuine familiarity with a subject. It constrains the form without providing the content.

Who this is useful for. Independent writers and journalists who want AI assistance that sounds like them, brand writers and editorial leads responsible for voice consistency across a team, and anyone who has found AI drafts technically acceptable but distinctly off-brand.