LUCA CSS — MCP Server for AI Coding Agents

Biological CSS immunity for AI agents. LUCA scans your code for silent bugs that browsers never report — before you deploy.

61 pathogens across 7 languages. 12 axioms. 3 compiled CSS profiles. Built from 130+ real bugs across 40+ sessions.

What it does

| Tool | When | What | |------|------|------| | css_preflight | Before coding | Get pathogens to avoid + axioms for your language | | css_scan | After coding | Scan for infections (critical/high) and warnings | | css_compile | Anytime | Compile production-ready CSS (dashboard, vitrine, ecommerce) |

Quick start

1. Install

pip install httpx

2. Configure your MCP client

Add to your MCP settings:

{
  "mcpServers": {
    "luca-css": {
      "command": "python3",
      "args": ["/path/to/luca_css_mcp.py"]
    }
  }
}

3. Use

• "Preflight CSS for a dark dashboard with hover animations"
• "Scan this code for anti-patterns"
• "Compile a vitrine CSS profile"

What LUCA catches

Real bugs that AI generates and browsers silently accept:

| ID | Bug | Impact | |----|-----|--------| | CSS_001 | var() used before :root declaration | Element renders without color | | CSS_002 | Empty grid-template-columns from unresolved template | Layout breaks completely | | CSS_004 | transition: all on hover with layout changes | 60fps reflows, janky UI | | CSS_007 | calc(100%-20px) without spaces | Silently ignored by browser | | CSS_008 | @keyframes animating width/height | Reflow every frame, 10fps | | CSS_009 | will-change on many elements | GPU memory exhaustion | | CSS_010 | @property without syntax field | Browser ignores registration | | CSS_011 | contain: strict on scrollable content | Breaks scroll and overflow |

Plus 53 more across Python, Bash, JavaScript, HTML, PowerShell, and Network.

Example: scan result

curl -s -X POST https://synthetic-context.net/css/api/scan \
  -H "Content-Type: application/json" \
  -d '{"code": ".sidebar { transition: all 0.3s; } @keyframes grow { from { width: 0 } to { width: 100% } }", "lang": "css"}'

{
  "infections": [
    {
      "id": "CSS_008",
      "title": "Layout-triggering property in animation — causes reflow every frame",
      "severity": "high",
      "fix": "Replace width/height with transform: scale(). Only animate transform and opacity for 60fps."
    }
  ],
  "warnings": [
    {
      "id": "CSS_004",
      "title": "transition:all on components with layout-changing hover",
      "severity": "medium",
      "fix": "Specify exact properties: transition: transform 0.2s, box-shadow 0.2s."
    }
  ],
  "clean": false
}

API

Public API at https://synthetic-context.net/css/api/:

| Endpoint | Method | Description | Rate | |----------|--------|-------------|------| | /compile | POST | Compile CSS profile | 30/min | | /preflight | POST | Pre-flight pathogen check | 30/min | | /scan | POST | Scan code for anti-patterns | 30/min | | /health | GET | Engine status + stats | 30/min |

Free. No signup. No API key required.

Configuration

Optional config file at ~/.luca/config.json:

{
  "api_url": "https://synthetic-context.net/css/api",
  "api_key": null
}

How it works

LUCA (Last Universal Common Ancestor) uses a biological model:

• Genome — CSS DNA: codons, profiles, design patterns
• Ribosome — Compiler: genome + profile = production CSS
• Membrane — Validator: rejects invalid output before it ships
• Pathogen DB — Immune memory: 61 real bugs that must never recur

Every pathogen comes from a real production incident. Not theory — lived experience across 40+ sessions.

Architecture

AI Agent ──→ MCP Client (this repo) ──→ LUCA API (server)
               luca_css_mcp.py              synthetic-context.net
               3 tools exposed              engine stays private
               httpx only                   source never exposed

The engine source code never leaves the server. You receive compiled CSS and scan results only.

License

MIT — Client (this file) is open source. Engine is proprietary (ECOBIO micro-enterprise).