What is Style Guide?
A style guide translates brand strategy into usable rules. For text that means: voice attributes with write-this/not-that examples, a banned-words list (filler phrases, superlatives, no-go terms), conventions for address, numbers, sources and punctuation. For design: colours, typography, spacing - ideally as design tokens rather than a PDF appendix.
The classic failure mode is the 40-page document nobody opens: too abstract for everyday writing, too long for a briefing. A useful style guide is a working document - short enough for one page, concrete enough that two authors hit the same sound with it. Example pairs beat lists of adjectives.
New is the third audience alongside team and agencies: machines. A machine-readable style guide travels into content tools as a system prompt and makes AI drafts testable - any text can be checked against the banned list and the example pairs, whether a human or a model wrote it. That keeps the voice consistent even as volume grows.
Why does Style Guide matter?
Without documented rules, every text renegotiates the brand - and now that roughly half of new articles on the web are AI-generated (Graphite analysis, 2026), the models’ default tone takes over wherever no style guide exists. The document is the difference between a voice and a random sound.
Style Guide in practice
- 01One page instead of forty: three voice attributes with example pairs, a banned-words list, rules for numbers and address - lives in the wiki and, identically, in the content tools’ system prompt.
- 02Mailchimp’s public content style guide is considered a reference: concrete rules per content type (newsletter, support, social) instead of abstract brand values.
- 03Editorial gate before publishing: check the text against the banned list and example pairs - passing means publishable, regardless of who wrote the draft.
