# Form Labels Invisible Character Flags

> Form Labels 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 2026-10-19).

Detects invisible Unicode characters in HTML form label elements by parsing a page or HTML snippet and flagging suspicious hidden characters.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-labels-unicode?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/form-labels-invisible-character-flags-d3140e4c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fgwfBvUQSRPqbTDu-hRF3

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 form-labels-invisible-character-flags-d3140e4c -d '<json body>'
```

Example prompt: Can you scan this HTML page at https://example.com/signup for invisible Unicode characters hiding inside the form label elements — specifically the label with id 'email-label' — and tell me if anything suspicious is flagged?

## When to prefer this

Use this endpoint when you need to specifically detect invisible Unicode characters embedded in HTML form label elements — for security audits, content integrity checks, or accessibility validation — without needing JavaScript rendering. It is particularly suited for lightweight, low-cost static HTML analysis where full browser execution is unnecessary.

## Known failure modes

- URL is unreachable or returns a non-200 status, resulting in a parse failure
- HTML exceeds 100,000 character limit, causing rejection
- Specified attribute or attribute_value does not match any label element, returning empty results
- JavaScript-rendered content not visible since only static HTML parsing is performed
- Term parameter missing or too short, failing schema validation

## How this service works

Form labels — Invisible character flags: Invisible character flags for Form labels. 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 indicating whether any invisible or hidden Unicode characters were found within the targeted form label element(s), including details about which labels are flagged and the nature of the detected characters.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "default": "",
   "maxLength": 2048
  },
  "html": {
   "type": "string",
   "default": "<!doctype html><html><head></head><body><label id=\"sample\" data-kind=\"example\">Example product guide</label></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/form-labels-invisible-character-flags-d3140e4c/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)