Guide January 26, 2026 · 5 min read

Creating Custom Style Packs

Learn how to define your brand voice, vocabulary rules, and forbidden patterns in YAML. A style pack is the heart of StyleMCP—it tells the system exactly what your brand sounds like.

What's in a Style Pack?

A style pack is a YAML file that defines your brand's writing rules. It contains:

  • Vocabulary rules: Words to prefer, avoid, or forbid entirely
  • Pattern rules: Regex patterns to catch structural issues
  • Tone settings: Formality level, sentence length, reading grade
  • Custom rules: Any brand-specific requirements

Basic Structure

Here's a minimal style pack to get you started:

my-brand.yaml 
name: "my-brand"
version: "1.0"
description: "Brand voice guidelines for My Company"

vocabulary:
  prefer:
    - "use"        # instead of "utilize"
    - "help"       # instead of "assist"
    - "start"      # instead of "commence"
  
  avoid:
    - "very"       # weak modifier
    - "really"     # weak modifier
    - "just"       # filler word
  
  forbid:
    - "leverage"
    - "synergy"
    - "circle back"

patterns:
  forbid:
    - pattern: "Click here"
      message: "Use descriptive link text"
    - pattern: "!!!+"
      message: "One exclamation point max"

Vocabulary Rules

Vocabulary rules control word choice at the individual word level.

Prefer vs Avoid vs Forbid

These three levels give you graduated control:

  • prefer: Suggests alternatives, doesn't fail validation
  • avoid: Flags as warning, minor score penalty
  • forbid: Fails validation, must be fixed

Replacement Mappings

You can specify exact replacements:

vocabulary:
  replacements:
    "utilize": "use"
    "purchase": "buy"
    "commence": "start"
    "terminate": "end"
    "regarding": "about"

When auto-rewrite is enabled, StyleMCP will automatically apply these replacements.

Pattern Rules

Pattern rules use regular expressions to catch structural issues that go beyond single words.

Common Patterns

patterns:
  forbid:
    # Cliché openers
    - pattern: "^In today's [\\w]+ world"
      message: "Avoid cliché openings"
    
    # Passive voice (simple detection)
    - pattern: "\\b(was|were|been|being) \\w+ed\\b"
      message: "Consider active voice"
      severity: "warning"
    
    # Vague CTAs
    - pattern: "[Cc]lick here"
      message: "Use descriptive link text"
    
    # Excessive punctuation
    - pattern: "[!?]{2,}"
      message: "Use single punctuation marks"
    
    # ALL CAPS (except acronyms)
    - pattern: "\\b[A-Z]{5,}\\b"
      message: "Avoid all-caps for emphasis"
⚠️ Regex Escaping

In YAML, backslashes need to be doubled (\\) for regex special characters. Alternatively, use single quotes for patterns: pattern: '\bword\b'

Tone Settings

Tone settings help enforce consistent voice beyond vocabulary:

tone:
  formality: "conversational"  # formal | professional | conversational | casual
  maxSentenceLength: 25        # words per sentence
  maxParagraphLength: 4        # sentences per paragraph
  readingLevel: 8              # target grade level (Flesch-Kincaid)
  contractions: "encouraged"   # required | encouraged | allowed | discouraged | forbidden

Industry-Specific Examples

SaaS / Tech

Avoid Prefer
"leverage our platform" "use our platform"
"seamless integration" "works with your tools"
"cutting-edge solution" describe what it actually does

Healthcare

Avoid Prefer
"patients" (if not clinical) "people" or "members"
"treatment plan" "care plan"
"compliance" "following your plan"

Finance

Avoid Prefer
"utilize funds" "use your money"
"fiscal responsibility" "managing your budget"
"accrue interest" "earn interest"

Testing Your Style Pack

Before deploying, test your style pack locally:

# Validate the style pack syntax
stylemcp pack validate my-brand.yaml

# Test against sample content
stylemcp validate --pack my-brand.yaml --file sample-content.txt

# Interactive testing
echo "Let's leverage synergies to circle back!" | stylemcp validate --pack my-brand.yaml

Uploading to StyleMCP Cloud

Once you're happy with your style pack, upload it to your account:

# Login to your account
stylemcp login

# Upload the style pack
stylemcp pack push my-brand.yaml

# Set as default for your account
stylemcp pack set-default my-brand

You can also manage style packs through the web dashboard.

Version Control Best Practices

Treat your style pack like code:

  • Keep it in version control (Git)
  • Use semantic versioning (1.0, 1.1, 2.0)
  • Document changes in a changelog
  • Test changes before deploying
A style pack is a living document. As your brand evolves, so should your rules.

Need a Starting Point?

Browse our library of pre-built style packs for common industries.

View Style Pack Library →