Output Artifacts: persona.md, design.md, style.md
Session 6.4 · ~5 min read
One Fingerprint, Three Documents
Your voice fingerprint captures everything about how you write. For production, this needs to be split into three operational documents, each serving a different purpose. Separating them allows you to mix and match: same persona with different design, same style with different persona, same design for a different content type.
The three documents are: persona.md (who is speaking), design.md (how content is structured), and style.md (writing mechanics). Together they replace the monolithic voice fingerprint with modular, reusable components.
Separation of concerns is not over-engineering. When you need to write a technical manual in your voice, you keep persona.md and style.md but swap design.md for a technical documentation template. When a collaborator writes under your brand, they use your style.md and design.md but their own persona.md. Modularity makes this possible.
The Three Documents
| Document | Answers | Changes When | Size |
|---|---|---|---|
| persona.md | Who is the author? What is their background? What do they believe? | Your career changes, your views evolve | 300-500 words |
| design.md | How is the content structured? What is the pacing? How do sections connect? | You change content types or formats | 300-500 words |
| style.md | What are the mechanical rules of the writing? Sentence length, vocabulary, punctuation? | Your writing habits evolve (slowly) | 300-500 words |
What Goes in persona.md
The persona document defines the human behind the writing. It is not a biography. It is a set of attributes that influence how the AI frames arguments and selects perspectives.
- Professional background: What you do, how long you have done it, what you have built
- Expertise areas: Where you speak from authority vs. where you are learning
- Worldview: Your operating assumptions about your field (e.g., "systems beat talent," "most best practices are untested folklore")
- Personality: How you handle disagreement, humor, uncertainty, strong opinions
What Goes in design.md
The design document defines content architecture. It controls the shape of the output, independent of voice.
- Opening pattern: Do you start with a story, a claim, a question, a data point?
- Section pacing: How long are sections? Do they accelerate toward the end?
- Argument structure: Do you present the conclusion first or build toward it?
- Closing pattern: Do you summarize, pose a question, or end with a practical step?
What Goes in style.md
The style document defines mechanical writing rules. These are the most directly actionable instructions for the AI.
- Sentence mechanics: Average length, range, fragment frequency, compound sentence rules
- Vocabulary: Preferred words, forbidden words, jargon policy
- Punctuation: Semicolons (yes/no), parenthetical asides (frequency), quotation marks (style)
- Forbidden patterns: Specific phrases, structures, or behaviors the AI must avoid
Combining Documents in Production
In your system prompt, concatenate the three documents with clear section headers. The AI processes all three as a unified set of instructions. The separation exists for your organizational benefit, not the AI's. You maintain three files. The AI sees one combined context.
For a blog post: persona.md + blog-design.md + style.md. For a technical document: persona.md + tech-design.md + style.md. For a social media post: persona.md + social-design.md + style.md. The persona and style stay constant. The design changes by format.
Further Reading
- Stylometry: How AI Detectors Identify Your Writing Style, Netus AI
- How to Find Your Writing Style So You Don't Sound Like AI, Vertech Academy
- AI Writing Tools: Powerful Ways to Preserve Authentic Voice
Assignment
Create all three files for your content production: persona.md, design.md, and style.md. Each should be 300-500 words. Test them by including all three in a system prompt and generating a piece of content. Does the output sound more like you than a default generation? Identify where it falls short and refine the document responsible for that dimension.