# Text Readability Analysis

> Text Readability Analysis is a paid API for AI agents from text-metrics.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-21).

Scores English text on six readability formulas (Flesch ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI) and returns a consensus grade level.

## Facts

- Endpoint: GET https://text-metrics.x402tookit.com/readability?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/text-readability-analysis-c84a5277
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fYT9dTUKfqJd6JmRPxE13

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability text-readability-analysis-c84a5277
```

Example prompt: Can you check the readability of this paragraph and tell me what grade level it's written at: 'The mitochondria is the powerhouse of the cell. It produces adenosine triphosphate through a series of complex biochemical reactions known as cellular respiration.'?

## When to prefer this

Use this endpoint when you need multi-formula readability scoring in a single call rather than computing individual metrics separately. It is ideal when you want a consensus grade rather than relying on a single index, and when you are working with English prose up to 3000 characters. Prefer it over grammar or style APIs when the primary question is reading-level difficulty rather than grammatical correctness or tone.

## Known failure modes

- Text exceeds 3000 character limit — request will fail or be truncated
- Non-English text input may produce unreliable or nonsensical scores
- Very short text (single words or very few sentences) may yield inaccurate results
- Missing required 'text' query parameter returns an error
- SMOG score may not be calculated if the text has fewer than 30 sentences

## How this service works

Readability of English text by Flesch ease, Flesch-Kincaid, Gunning fog, SMOG, Coleman-Liau and ARI, with a consensus grade.

## Output

Returns a JSON object with six individual readability scores (fleschReadingEase, fleschKincaidGrade, gunningFog, smog, colemanLiau, automatedReadabilityIndex), a consensusGrade, word count, sentence count, long-word count, a summary verdict, and optional reasons or disclaimer fields.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "text"
     ],
     "properties": {
      "text": {
       "type": "string",
       "description": "English text, up to 3000 characters"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "smog": {},
      "words": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "sentences": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "gunningFog": {
       "type": [
        "null",
        "number"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "colemanLiau": {
       "type": [
        "null",
        "number"
       ]
      },
      "consensusGrade": {
       "type": [
        "null",
        "number"
       ]
      },
      "fleschReadingEase": {
       "type": [
        "null",
        "number"
       ]
      },
      "fleschKincaidGrade": {
       "type": [
        "null",
        "number"
       ]
      },
      "longWords3PlusSyllables": {
       "type": [
        "null",
        "number"
       ]
      },
      "automatedReadabilityIndex": {
       "type": [
        "null",
        "number"
       ]
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/text-readability-analysis-c84a5277/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from text-metrics.x402tookit.com](https://www.zero.xyz/host/text-metrics.x402tookit.com/llms.txt)