# AISkills402: UI Worst-Case Data Generator

> AISkills402: UI Worst-Case Data Generator is a paid API for AI agents from api.aiskills402.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-31).

Generates stress-test JSON data for UI components by producing worst-case values for every prop in a given TypeScript type or prop list

## Facts

- Endpoint: GET https://api.aiskills402.com/v1/skills/ui-worst-case-data/file?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/aiskills402-ui-worst-case-data-generator-1e545a81
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_T4yBB8pyJUsjAd1l_hDD1

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 aiskills402-ui-worst-case-data-generator-1e545a81
```

Example prompt: Generate worst-case JSON test data for my React component that has these props: `label: string`, `items: string[]`, `count: number`, and `icon?: string` — I want to stress-test how it renders with empty strings, super-long words, RTL text, emoji, zero and huge numbers, and empty or hundred-item lists.

## When to prefer this

Use this endpoint when you need to systematically stress-test how a UI component renders under boundary and edge-case conditions — particularly for string overflow, bidirectional text, emoji rendering, empty states, and numeric extremes. Prefer it over manually crafting test fixtures when covering all prop types exhaustively. It is specifically designed for UI component props expressed as TypeScript types or prop lists, not for general data mocking or backend API testing.

## Known failure modes

- Invalid or unparseable TypeScript type input may result in an error or incomplete output
- Ambiguous prop types may produce generic rather than targeted worst-case values
- Network or payment authorization failure returns HTTP 402 requiring x402 payment header
- Very complex nested TypeScript generics may not be fully resolved

## How this service works

UI Worst-Case Data — Turns the props of a UI component (a TypeScript type or a list of props) into strict JSON test data that stresses how it displays, and nothing else. Per prop it picks the worst values for the type, a string that is empty, one word of eighty characters with no space, on two lines, an emoji joined with a zero-width joiner, right-to-left letters or HTML-looking text, numbers at zero and at the large and decimal ends, lists that are empty, hold one item or hold a hundred, optio…

## Output

A JSON object containing worst-case test values for each prop in the provided UI component type. For string props: empty string, an 80-character word without spaces, a two-line string, an emoji with zero-width joiner, RTL text, and HTML-looking text. For number props: zero, a very large number, and a decimal. For array props: empty array, single-item array, and hundred-item array. For optional props: both present and absent variants. The output is structured to directly stress-test UI rendering edge cases.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/aiskills402-ui-worst-case-data-generator-1e545a81/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.aiskills402.com](https://www.zero.xyz/host/api.aiskills402.com/llms.txt)