# Aside Blocks — Invisible Character Flags

> Aside Blocks — Invisible Character Flags 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).

Detects and reports invisible Unicode characters within HTML aside elements on a given webpage or supplied HTML snippet.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-asides-unicode?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-invisible-character-flags-c52c42e8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IT6bHoBwjCR7noA832zdC

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-invisible-character-flags-c52c42e8 -d '<json body>'
```

Example prompt: Check this page for invisible Unicode characters hidden inside aside blocks — the URL is https://example.com/docs/product-guide, look in the element with id 'sidebar', and flag anything unusual compared to these previous texts: ['Older example'].

## When to prefer this

Choose this endpoint when you need to specifically audit aside/sidebar HTML elements for invisible Unicode characters or steganographic markers using static HTML parsing. It is ideal for content integrity checks, security audits of third-party HTML, or detecting hidden text manipulation in documentation sidebars, without requiring JavaScript execution or login.

## Known failure modes

- URL is inaccessible or returns non-200 response
- HTML exceeds 100,000 character limit
- Attribute name does not match pattern requirements
- Term is empty or exceeds 100 characters
- JavaScript-rendered content not available since only static parsing is performed
- No aside elements found matching the specified attribute/value

## How this service works

Aside blocks — Invisible character flags: Invisible character flags 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 invisible character flags result.

## Output

Returns a bounded result containing identified invisible Unicode character flags found within aside elements of the parsed page or HTML, including details about their positions and types relative to the specified attribute and term.

## 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-invisible-character-flags-c52c42e8/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)