# agent402.tools Readability Score

> agent402.tools Readability Score is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Computes four standard readability metrics (Flesch-Kincaid Grade Level, Flesch Reading Ease, Gunning Fog Index, Automated Readability Index) plus word, sentence, and syllable counts from input text.

## Facts

- Endpoint: POST https://agent402.tools/api/readability-score
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-tools-readability-score-00ea4f73
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2W_Yh5SahJMH9dRFbjGuG

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 agent402-tools-readability-score-00ea4f73 -d '<json body>'
```

Example prompt: Can you check the readability of this paragraph and give me the Flesch-Kincaid grade level, Flesch Reading Ease, Gunning Fog, and ARI scores: 'The mitochondria is the powerhouse of the cell, generating ATP through oxidative phosphorylation in a highly regulated biochemical process.'?

## When to prefer this

Choose this endpoint when you need multiple standard readability metrics computed in a single call rather than individually. It is ideal when you want both grade-level estimates (Flesch-Kincaid, Gunning Fog, ARI) and an ease score (Flesch Reading Ease) together, along with raw linguistic counts (words, sentences, syllables) for further analysis.

## Known failure modes

- Text shorter than 10 characters returns a validation error
- Empty or missing 'text' field returns a 400 bad request
- Very short single-word inputs may produce unreliable or zero-division scores
- Payment not included or insufficient USDC returns a 402 Payment Required response

## How this service works

Compute Flesch-Kincaid Grade Level, Flesch Reading Ease, Gunning Fog Index, and Automated Readability Index from text. Returns all 4 scores plus word, sentence, and syllable counts.

## Output

Returns all four readability scores (Flesch-Kincaid Grade Level, Flesch Reading Ease, Gunning Fog Index, Automated Readability Index) plus the word count, sentence count, and syllable count derived from the submitted text.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "description": "Text to analyze (min 10 chars)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "words": 16,
  "sentences": 3,
  "syllables": 17,
  "gunningFog": 3.2,
  "fleschReadingEase": 104.59,
  "fleschKincaidGrade": -0.89,
  "automatedReadability": -2.84
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-tools-readability-score-00ea4f73/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)