# Readability Calculator — MCP tool `findutils:readability_calculator`

Compute six readability scores for English text (Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, Automated Readability Index) plus an average grade level, a reading-level label, a target audience, and text statistics. Scores are null when the text has fewer than 10 words.

- Category: education
- MCP server: https://mcp.findutils.com/ (Streamable HTTP, no API keys, 120 req/min per IP)
- REST endpoint: POST https://api.findutils.com/api/tools/readability-calculator/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/mcp/readability-calculator/
- Same tool on the other surface: https://findutils.com/api/readability-calculator/

## Connect

```bash
claude mcp add findutils --transport http https://mcp.findutils.com/
```

Claude Desktop (`claude_desktop_config.json`):

```json
{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}
```

## Call the tool (verified example)

```bash
curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "readability_calculator",
      "arguments": {
        "text": "The cat sat on the mat. The dog sat on the rug. Both were happy."
      }
    }
  }'
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `text` | string | yes | The text to analyse (at least 10 words for scores). |

Example arguments (verified):

```json
{
  "text": "The cat sat on the mat. The dog sat on the rug. Both were happy."
}
```

## Also a REST endpoint

```bash
curl -X POST https://api.findutils.com/api/tools/readability-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "text": "The cat sat on the mat. The dog sat on the rug. Both were happy."
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/readability-calculator
```

Full REST reference: https://findutils.com/api/readability-calculator/ · OpenAPI 3.1 spec: https://findutils.com/api/openapi.json

---
Full catalog: POST https://mcp.findutils.com/ with method `tools/list` · https://findutils.com/mcp/ · https://findutils.com/llms.txt