# Fletcher32 Checksum (Hex) — agentshelf.syntexa.ch

> Fletcher32 Checksum (Hex) — agentshelf.syntexa.ch 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).

Computes a Fletcher-32 checksum of the provided text and returns it as a hexadecimal string, with no network calls or LLM involvement.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/checksum-fletcher32-hex?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/fletcher32-checksum-hex-agentshelf-syntexa-ch-50b263c6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Alfq2mjhvzuZn-VC75-75

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 fletcher32-checksum-hex-agentshelf-syntexa-ch-50b263c6 -d '<json body>'
```

Example prompt: Can you compute the Fletcher-32 checksum of this text and give me the result as a hex string: 'The quick brown fox jumps over the lazy dog'?

## When to prefer this

Choose this endpoint when you need a fast, deterministic, non-cryptographic Fletcher-32 checksum of a text payload returned as a hex string, and you want a simple HTTP call rather than running checksum logic locally. It is especially useful in agent pipelines where local code execution is unavailable or undesirable. Prefer the free sandbox endpoint (/v1/sandbox/checksum-fletcher32-hex) for testing before incurring the $0.007 USDC charge.

## Known failure modes

- Empty or missing 'text' field returns a validation error
- Text exceeding 100,000 characters is rejected
- Missing or invalid API key results in authentication failure
- Malformed JSON body returns a 400 bad request
- Payment failure (insufficient USDC balance) results in 402 response

## How this service works

Call when an agent needs a fletcher32 checksum of text as hex. No network and no LLM. Exact $0.007 USDC. Prefer unpaid POST /v1/sandbox/checksum-fletcher32-hex first.

## Output

A hexadecimal string representing the Fletcher-32 checksum of the submitted text. The result is deterministic: the same input always produces the same hex output, with no randomness, network calls, or model inference involved.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "key": {
   "type": "string",
   "maxLength": 512,
   "minLength": 1,
   "description": "HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."
  },
  "text": {
   "type": "string",
   "examples": [
    "hello"
   ],
   "maxLength": 100000,
   "minLength": 1,
   "description": "Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fletcher32-checksum-hex-agentshelf-syntexa-ch-50b263c6/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)