About
Universal CSS analysis and documentation MCP server with 150+ metrics
README
Code style: crackerjack Runtime: oneiric Framework: FastMCP uv Python: 3.13+
Universal CSS Analysis and Documentation MCP Server. Analyze any CSS with 150+ metrics for complexity, specificity, and quality.
Features
- CSS Analysis: 150+ metrics for CSS complexity, specificity, and quality
- MDN Documentation: Fetch CSS property docs from MDN Web Docs
- Browser Compatibility: Check cross-browser support for CSS properties
- Project Analysis: Analyze all CSS files in a project
Installation
# Using uv
uv pip install css-mcp
# Using pip
pip install css-mcp
Usage
Start Server
# Via CLI
css-mcp
# Via Python module
python -m css_mcp.server
Environment Variables
| Variable | Default | Description |
|---|---|---|
CSS_MCP_HTTP_PORT |
3050 | Server port |
CSS_MCP_HTTP_HOST |
localhost | Server host |
CSS_MCP_DEBUG |
false | Enable debug mode |
Available Tools
| Tool | Description |
|---|---|
analyze_css |
Full CSS analysis with 150+ metrics |
analyze_css_summary |
Quick CSS summary (faster) |
get_docs |
MDN documentation for CSS properties |
get_browser_compatibility |
Check browser support for properties |
search_properties |
Search for CSS properties |
get_properties_by_category |
Get properties by category |
analyze_project_css |
Analyze all CSS in a project |
list_capabilities |
List available capabilities |
health_check |
Check server health |
Programmatic Usage
Use the analyzer directly in Python for any CSS:
Example: Analyze Any CSS
from css_mcp.analyzer import CSSAnalyzer
# Analyze any CSS content
analyzer = CSSAnalyzer()
metrics = analyzer.analyze(css_content)
# Get complexity score
print(f"Complexity: {metrics.complexity_score}/100")
# Get optimization suggestions
suggestions = analyzer.get_suggestions()
Metrics
The analyzer provides 150+ metrics including:
Basic Metrics
- Total rules, selectors, properties
- File size (bytes, gzipped)
- Lines of code
Selector Metrics
- ID, class, element, universal selectors
- Pseudo-classes and pseudo-elements
- Combinators (descendant, child, sibling)
- Selector depth
Specificity Metrics
- Average, min, max specificity
- High specificity rules
- Specificity distribution
Property Metrics
- Unique properties
- Category distribution (layout, typography, etc.)
- Vendor prefixes
!importantusage- CSS custom properties
Quality Metrics
- Duplicate selectors
- Duplicate properties
- Empty rules
- Complexity score
- Efficiency scores
Browser Compatibility
Built-in compatibility data for common CSS properties across:
- Chrome
- Firefox
- Safari
- Edge
Development
# Install dev dependencies
uv sync --group dev
# Run tests
pytest
# Type check
mypy css_mcp
# Lint
ruff check css_mcp
License
BSD-3-Clause
Installing Css
This server has no published package — it is built from source. Open the repository and follow its README.
▸ github.com/lesleslie/css-mcpFAQ
Is Css MCP free?
Yes, Css MCP is free — one-click install via Unyly at no cost.
Does Css need an API key?
No, Css runs without API keys or environment variables.
Is Css hosted or self-hosted?
Self-hosted: the server runs locally on your machine via the install command above.
How do I install Css in Claude Desktop, Claude Code or Cursor?
Open Css on unyly.org, pick your client tab (Claude Desktop, Claude Code, Cursor) and press Install — the config is generated automatically, no JSON editing.
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