# Aside Blocks Attribute Presence Check

> Aside Blocks Attribute Presence Check is a paid API for AI agents from market.datapackvibe.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-17).

Checks whether a specified HTML attribute (optionally with a given value) is present on aside elements in a webpage or supplied HTML snippet.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-asides-attribute-presence?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/aside-blocks-attribute-presence-check-e6789f88
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9CNeW7GzvDr5N_U1PVUme

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 aside-blocks-attribute-presence-check-e6789f88 -d '<json body>'
```

Example prompt: Check whether the aside blocks on https://example.com/blog-post have a data-kind attribute with the value 'sidebar' — just do a static HTML parse, no JavaScript needed.

## When to prefer this

Use this endpoint when you need a lightweight, static-HTML-only check for attribute presence on aside HTML elements specifically — ideal for CI/CD pipelines, CMS audits, or accessibility checks where JavaScript rendering is unnecessary and cost must be minimal ($0.01 per call).

## Known failure modes

- URL is unreachable or returns a non-200 HTTP status
- HTML exceeds the 100,000 character maximum
- Attribute name does not match required pattern (must start with a letter, max 50 chars)
- Term is empty or exceeds 100 characters
- No aside elements found in the document
- JavaScript-rendered content not reflected (static parsing only)
- Payment not processed, endpoint returns 402

## How this service works

Aside blocks — Attribute presence check: Attribute presence check for Aside blocks. One public HTTPS page or supplied HTML; static parsing, no JavaScript rendering, login or access bypass. Specialised preset in a shared 50-profile, 20-operation engine. 0.01 USDC includes one bounded attribute presence check result.

## Output

Returns a bounded attribute presence check result indicating whether the specified attribute (and optionally its value) exists on aside block elements found in the parsed HTML of the given URL or supplied HTML string.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "default": "",
   "maxLength": 2048
  },
  "html": {
   "type": "string",
   "default": "<!doctype html><html><head></head><body><aside id=\"sample\" data-kind=\"example\">Example product guide</aside></body></html>",
   "maxLength": 100000
  },
  "term": {
   "type": "string",
   "default": "product",
   "maxLength": 100,
   "minLength": 1
  },
  "attribute": {
   "type": "string",
   "default": "id",
   "pattern": "^[a-zA-Z][a-zA-Z0-9:_-]{0,49}$",
   "maxLength": 50
  },
  "previous_texts": {
   "type": "array",
   "items": {
    "type": "string",
    "default": "",
    "maxLength": 1000
   },
   "default": [
    "Older example"
   ],
   "maxItems": 200,
   "minItems": 0
  },
  "attribute_value": {
   "type": "string",
   "default": "sample",
   "maxLength": 200
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aside-blocks-attribute-presence-check-e6789f88/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.datapackvibe.com](https://www.zero.xyz/host/market.datapackvibe.com/llms.txt)