StyleMCP
Executable brand rules for AI models and agents. Keep every AI-generated message on-brand.
What is StyleMCP?
StyleMCP validates and rewrites AI-generated text to match your brand voice. Use it as:
- REST API - Validate text from any application
- MCP Server - Direct integration with Claude and other AI agents
- CLI - Check copy in your terminal or CI/CD
- GitHub Action - Catch off-brand copy in pull requests
Quick Start
API
curl -X POST https://stylemcp.com/api/validate \
-H "Content-Type: application/json" \
-d '{"text": "Click here to learn more!"}'
Response:
{
"valid": false,
"score": 65,
"violations": [
{
"rule": "no-click-here",
"severity": "error",
"message": "Avoid 'click here' - describe the destination instead",
"suggestion": "Learn more about our features"
}
]
}
CLI
# Install
npm install -g stylemcp
# Validate text
stylemcp validate "Click here to learn more"
# Validate file
stylemcp validate src/copy/homepage.json --pack saas
# Rewrite text
stylemcp rewrite "Please utilize our product" --mode aggressive
MCP (Claude Desktop)
Add to your claude_desktop_config.json:
{
"mcpServers": {
"stylemcp": {
"command": "npx",
"args": ["stylemcp"]
}
}
}
Now Claude can validate and rewrite text using your brand rules.
API Endpoints
| Method | Endpoint | Description |
|---|---|---|
| POST | /api/validate | Validate text against brand rules |
| POST | /api/rewrite | Rewrite text to match brand voice |
| POST | /api/validate/batch | Validate multiple texts |
| GET | /api/packs | List available style packs |
| GET | /api/packs/{pack}/voice | Get voice guidelines |
| GET | /api/packs/{pack}/ctas | Get CTA rules |
| GET | /api/mcp/sse | MCP SSE endpoint |
| POST | /api/mcp/call | MCP tool calls |
Style Packs
StyleMCP uses style packs - YAML files that define your brand rules.
Available Packs
| Pack | Best For | Key Features |
|---|---|---|
saas | B2B SaaS products | Professional, clear, helpful tone |
ecommerce | DTC & retail brands | Friendly, conversion-focused, no pushy CTAs |
healthcare | Medical & wellness | Compliant language, no cure claims, person-first |
finance | Fintech & banking | Precise, risk-aware, no guaranteed returns |
Example: saas Pack
- Vocabulary: Prefer "use" over "utilize", "help" over "assist"
- Forbidden words: "synergy", "leverage", "cutting-edge", "game-changing"
- Patterns to avoid: "click here", "we're sorry for any inconvenience"
- CTA rules: Avoid "Submit", "Click here", "OK" - prefer "Save", "Create", "Sign up"
Pack Structure
packs/
my-brand/
manifest.yaml # Pack metadata
voice.yaml # Tone, vocabulary, forbidden words
copy_patterns.yaml # Reusable copy templates
cta_rules.yaml # Button/CTA guidelines
tokens.json # Design tokens (optional)
Create Your Own Pack
# Copy the default pack
cp -r packs/saas packs/my-brand
# Edit the rules
nano packs/my-brand/voice.yaml
# Use your pack
curl -X POST https://stylemcp.com/api/validate \
-d '{"text": "Your text", "pack": "my-brand"}'
voice.yaml Example
tone:
summary: "Friendly, clear, and helpful"
attributes:
- name: friendly
weight: 0.8
- name: professional
weight: 0.7
vocabulary:
rules:
- preferred: "use"
avoid: ["utilize", "leverage"]
- preferred: "help"
avoid: ["assist", "facilitate"]
forbidden:
- "synergy"
- "paradigm shift"
- "game-changing"
doNot:
- pattern: "click here"
reason: "Poor accessibility"
suggestion: "Describe the destination"
severity: error
- pattern: "\\b(obviously|simply|just)\\b"
isRegex: true
reason: "Can make users feel stupid"
severity: warning
Self-Hosting
Docker
# Clone the repo
git clone https://github.com/3DUNLMTD/stylemcp.git
cd stylemcp
# Set up environment
echo "STYLEMCP_API_KEY=$(openssl rand -hex 32)" > .env
# Run with Docker
docker compose up -d
# Check health
curl http://localhost:3000/health
Manual
# Install dependencies
npm install
# Build
npm run build
# Start server
npm start
GitHub Actions
name: Brand Check
on: [pull_request]
jobs:
validate:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Validate copy
run: |
npx stylemcp validate src/copy/*.json \
--min-score 80 \
--format github
Environment Variables
| Variable | Description | Default |
|---|---|---|
PORT | Server port | 3000 |
STYLEMCP_API_KEY | API key for authentication | (none) |
GITHUB_WEBHOOK_SECRET | GitHub webhook secret | (none) |
MCP Tools
When used as an MCP server, StyleMCP provides these tools:
| Tool | Description |
|---|---|
validate_text | Validate text against brand rules |
rewrite_to_style | Rewrite text to match brand voice |
get_voice_rules | Get voice and tone guidelines |
get_copy_patterns | Get approved copy patterns |
get_cta_rules | Get CTA guidelines |
get_tokens | Get design tokens |
list_packs | List available style packs |
What Gets Validated?
The saas pack checks for:
Vocabulary
- Use simple words: "use" not "utilize", "help" not "assist"
- Avoid jargon: "synergy", "leverage", "paradigm shift"
- Avoid weak intensifiers: "very", "really", "extremely"
Patterns
- No "click here" (accessibility issue)
- No "we're sorry for any inconvenience" (corporate non-apology)
- No double "please" (sounds desperate)
- No starting with "Sorry" (lead with solutions)
CTAs
- Avoid generic: "Submit", "OK", "Yes/No", "Click here"
- Use specific actions: "Save", "Create", "Sign up", "Export"
- Max 4 words
Constraints
- Max 25 words per sentence
- No exclamation marks (in most contexts)
- First-person plural ("we", "our")
- Oxford comma
License
MIT