# Agentshelf Character 3-gram Counter

> Agentshelf Character 3-gram Counter is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.007/call, status unknown (last checked 2026-10-02).

Counts all character-level 3-grams (trigrams) in the provided text and returns their frequencies

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/ngram-char-3?utm_source=zero.xyz
- Price: $0.007/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-character-3-gram-counter-c1265d4c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XdG_NyhYchpMp1C68vmj-

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 agentshelf-character-3-gram-counter-c1265d4c -d '<json body>'
```

Example prompt: Count all character-level 3-grams in this text and give me the frequency of each: 'The quick brown fox jumps over the lazy dog.'

## When to prefer this

Use this endpoint when you need exact character-level trigram counts without any external network calls or LLM inference — it is a pure deterministic computation. Prefer this over building your own n-gram logic when you want a reliable, pay-per-call microservice. Try the free sandbox endpoint POST /v1/sandbox/ngram-char-3 first to validate your integration before paying.

## Known failure modes

- Empty or missing 'text' field returns an error — minLength is 1
- Text exceeding 100,000 characters returns a validation error
- Payment of exactly $0.007 USDC required via x402; insufficient payment results in 402 response
- Malformed JSON body returns a 400 error

## How this service works

Call when an agent needs counts of char 3-grams. No network and no LLM. Exact $0.007 USDC. Prefer unpaid POST /v1/sandbox/ngram-char-3 first.

## Output

A map of every unique 3-character sequence (trigram) found in the input text, with each trigram as a key and its occurrence count as the value. The response is computed locally without network or LLM calls.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "examples": [
    "ab ab"
   ],
   "maxLength": 100000,
   "minLength": 1,
   "description": "Input for this SKU. The route description says whether it is plain text, a URL, base64 bytes, or an already-encoded token."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-character-3-gram-counter-c1265d4c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)