mcp-readability

Calculate readability scores and text complexity metrics for content optimization.

Install in Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "readability": {
      "command": "npx",
      "args": ["-y", "mcp-readability"]
    }
  }
}

Restart Claude Desktop. The analyze_readability tool is now available.

Tools

| Tool | Description | |------|-------------| | analyze_readability | Computes FK Reading Ease, FK Grade Level, SMOG Index, and ARI scores with reading level, audience label, text stats, and improvement suggestions |

Scores computed

| Score | Formula | What it means | |-------|---------|---------------| | Flesch Reading Ease | 206.835 − 1.015×(W/S) − 84.6×(Syl/W) | 0–100; higher = easier. 60–70 = plain English | | Flesch-Kincaid Grade | 0.39×(W/S) + 11.8×(Syl/W) − 15.59 | US school grade level required to understand | | SMOG Index | 3 + √(polysyllables × 30/sentences) | Grade level; best for health/consumer text | | ARI | 4.71×(C/W) + 0.5×(W/S) − 21.43 | Grade level based on character and word counts |

Reading level mapping (FK Grade)

| Grade | Level | Audience | |-------|-------|----------| | < 6 | Elementary | General public / young readers | | 6–8 | Middle School | Middle school students | | 9–12 | High School | High school students | | 13–16 | College | College students / professionals | | 17+ | Graduate | Graduate students / specialists |

Example

{
  "method": "tools/call",
  "params": {
    "name": "analyze_readability",
    "arguments": {
      "text": "The cat sat on the mat. It was a big mat. The cat liked it.",
      "include_suggestions": true
    }
  }
}

Response:

{
  "scores": {
    "flesch_reading_ease": 92.5,
    "flesch_kincaid_grade": 1.8,
    "smog_index": 3.0,
    "ari": 0.9
  },
  "reading_level": "Elementary (under 6th grade)",
  "audience": "General public / young readers",
  "stats": {
    "word_count": 18,
    "sentence_count": 3,
    "syllable_count": 18,
    "avg_words_per_sentence": 6.0,
    "avg_syllables_per_word": 1.0
  },
  "suggestions": ["No major readability issues found — text looks good for the target audience."],
  "summary": "Flesch Reading Ease: 92.5 | FK Grade: 1.8 | SMOG: 3.0 | ARI: 0.9 — Elementary (under 6th grade) (18 words, 3 sentences)"
}

Dev

npm install
npm run build
echo '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}' | node dist/index.js

Part of Cosmic API

This MCP server is part of the Cosmic API collection. Browse all tools: npm search mcp cosmic-api