# X-Content-Type-Options Header Check

> X-Content-Type-Options Header Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-20).

Validates whether an HTTP response's X-Content-Type-Options header is exactly 'nosniff', returning a deterministic pass/advisory finding as versioned JSON.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/x-content-type-options-check?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x-content-type-options-header-check-b7bb89a9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3G9b8YOB8FVC-hioM4i16

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 x-content-type-options-header-check-b7bb89a9 -d '<json body>'
```

Example prompt: Check whether this HTTP header value passes the X-Content-Type-Options nosniff requirement: 'nosniff'.

## When to prefer this

Use this endpoint when an AI agent or automated pipeline needs a deterministic, auditable, versioned record of whether an HTTP response's X-Content-Type-Options header is correctly set before taking actions such as caching, redirecting, retrying, or accepting the response. Prefer this over custom logic when you need consistent normalized evidence and explicit pass/advisory classification without writing your own header parsing.

## Known failure modes

- Empty or missing value field returns advisory/fail status
- Header value with incorrect casing (e.g. 'Nosniff') may trigger advisory depending on normalization
- Value exceeding 8192 characters may be rejected
- Malformed JSON input returns validation error
- Any value other than exact 'nosniff' results in advisory finding

## How this service works

X Content Type Options Check: X Content Type Options Check checks whether X-Content-Type-Options is exactly nosniff from bounded caller-supplied values without an external provider. Call X Content Type Options Check before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for X Content Type Options Check as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. F…

## Output

Returns a versioned deterministic JSON object containing: the normalized input header evidence, a computed finding describing whether the value matches exactly 'nosniff', and an explicit pass or advisory status indicating compliance with X-Content-Type-Options security requirements.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "value": {
   "type": "string",
   "maxLength": 8192,
   "description": "Value supplied to X Content Type Options Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "value": "nosniff",
   "accepted": true
  },
  "schema": "delx/util-x-content-type-options-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "bea2556c6cc6e1b92f986ac1504063041a0fbd184228061905e268ef7eeebd31",
   "external_calls": 0
  },
  "operation": "web_reliability:x_content_type_options_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x-content-type-options-header-check-b7bb89a9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)