# Button Labels — Invisible Character Flags

> Button 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 2026-10-17).

Detects invisible Unicode characters in button label text on a webpage or supplied HTML, flagged by element attribute matching.

## Facts

- Endpoint: POST https://market.datapackvibe.com/x402/assistant-bx-web-buttons-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/button-labels-invisible-character-flags-a807c630
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_V4biXOb7dEAtFqB58I7Gk

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 button-labels-invisible-character-flags-a807c630 -d '<json body>'
```

Example prompt: Can you check the button with id 'submit-btn' on https://example.com for any invisible Unicode characters in its label text, using the term 'submit'?

## When to prefer this

Choose this endpoint when you need to detect invisible or non-printable Unicode characters specifically within button label text on a static HTML page or supplied HTML snippet. It is ideal for content auditing, accessibility validation, or security checks where hidden Unicode glyphs in UI button text could cause display, SEO, or injection issues. Prefer this over general text scanners when you need to target specific button elements by HTML attribute.

## Known failure modes

- URL is unreachable or returns non-200 status — no content to parse
- HTML exceeds 100,000 character limit — request rejected
- No button element matches the specified attribute/value pair — empty or null result
- Term not found in matched button label — no flags generated
- Invalid attribute name format — schema validation error
- JavaScript-rendered buttons not visible — static parser cannot detect them

## How this service works

Button labels — Invisible character flags: Invisible character flags for Button 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 invisible Unicode characters were detected in the matched button label, along with details about the flagged characters and the button element identified by the specified attribute and value.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "default": "",
   "maxLength": 2048
  },
  "html": {
   "type": "string",
   "default": "<!doctype html><html><head></head><body><button id=\"sample\" data-kind=\"example\">Example product guide</button></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/button-labels-invisible-character-flags-a807c630/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)