One of the fastest ways to lose trust in an assistant is inconsistency. Tone changes across sessions, answers vary in structure, and users cannot predict what they will get. Style guides make outputs more usable and more "product-like".
Define what "good" looks like
A style guide should be concrete. Define:
- Structure. Summary first, then details, then sources.
- Language. Plain language, no jargon unless needed.
- Uncertainty. How to express uncertainty and request clarification (see UX patterns).
- Safety and boundaries. How to refuse politely and offer next steps (see user transparency).
Use templates and examples
Style guides work best as examples, not paragraphs. Provide:
- 3-5 canonical response templates.
- Positive examples of tone and structure.
- Negative examples to avoid (overconfident, verbose, inconsistent citations).
Make citations part of the style
If the assistant uses RAG, make citations predictable: where they appear, how they are labelled, and how conflicts are handled (see citations and grounding).
Keep style stable across changes
Style is fragile under prompt updates. Protect it with:
- Regression cases for tone and structure (see prompt regression testing).
- Rubric scoring for helpfulness and appropriateness (see evaluation rubrics).
- Feature flags and canaries so shifts are reversible (see feature flags).
Align style to accessibility
Consistent structure improves accessibility: headings, short paragraphs, and predictable source sections help users who rely on screen readers or keyboard navigation (see accessibility patterns).
A style guide is a product control. It turns a general-purpose model into an experience that feels intentional, reliable and aligned to your brand.