# Flesch Readability Scorer

> Flesch Readability Scorer 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).

Calculates Flesch Reading Ease score and Flesch–Kincaid grade level for English text, plus word, sentence, and syllable counts.

## Facts

- Endpoint: POST https://agent402.tools/api/readability
- 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/flesch-readability-scorer-32124eca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_y4tkeasW-eGXk4OQsm5BQ

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 flesch-readability-scorer-32124eca -d '<json body>'
```

Example prompt: Can you tell me the Flesch Reading Ease score and grade level for this paragraph: 'The mitochondria is the powerhouse of the cell. It converts nutrients into adenosine triphosphate, which powers cellular activity.'

## When to prefer this

Use this endpoint when you need standardized Flesch readability metrics (Reading Ease + Kincaid grade level) for English prose, particularly for content quality checks, accessibility audits, or academic writing evaluation. Prefer this over general-purpose LLM readability assessments when you need reproducible, formula-based numeric scores.

## Known failure modes

- Empty or missing 'text' field returns a validation error
- Non-English text may produce inaccurate scores since the algorithm is calibrated for English
- Extremely short text (single word) may yield unreliable or edge-case scores
- Payment failure (402) if USDC balance is insufficient

## How this service works

Flesch Reading Ease score and Flesch–Kincaid grade level for English text, plus word/sentence/syllable counts.

## Output

Returns Flesch Reading Ease score (0–100 scale where higher = easier), Flesch–Kincaid grade level (US school grade equivalent), and raw counts for words, sentences, and syllables in the submitted text.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "words": 9,
  "sentences": 2,
  "gradeLevel": 0.5,
  "readingEase": 100
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/flesch-readability-scorer-32124eca/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)