# Tempo Halowerk – Script Time-to-First-Paint Checker

> Tempo Halowerk – Script Time-to-First-Paint Checker is a paid API for AI agents from tempo.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Measures the time-to-visible-render-start (first paint) for a script object at a given public URL.

## Facts

- Endpoint: POST https://tempo.halowerk.com/v1/pruef/tempo/renderstart/skript
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tempo-halowerk-script-time-to-first-paint-checker-af852d80
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mo5FubPBcGl7iyT7qoq24

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 tempo-halowerk-script-time-to-first-paint-checker-af852d80 -d '<json body>'
```

Example prompt: Check how long it takes for the script at https://cdn.example.com/app.js to start visibly rendering — give me the time-to-first-paint figure.

## When to prefer this

Choose this endpoint when you specifically need the time-to-visible-render-start metric for a script resource (as opposed to DNS resolution time, TTFB, or total load time). It is ideal for diagnosing render-blocking JavaScript, auditing third-party script impact on perceived performance, or setting CI gates on first-paint timing for JS bundles.

## Known failure modes

- Target URL is not publicly reachable — connection refused or DNS failure
- URL exceeds the 2048-character maximum length
- Script resource returns a non-200 HTTP status, making timing measurement impossible
- CSS selector provided matches no element or is ambiguous
- Rendering environment times out waiting for paint event
- Invalid or malformed URL provided in the 'ziel' field

## How this service works

Prüft am Objekt skript den Befund Zeit bis zum sichtbaren Renderstart.

## Output

Returns the measured time-to-visible-render-start (first paint) for the specified script resource, expressed as a duration value. This is the performance finding for the 'skript' object type scoped to 'renderstart' timing.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "ziel": {
   "oneOf": [
    {
     "type": "string",
     "maxLength": 2048,
     "minLength": 1,
     "description": "Öffentliche HTTP(S)-Adresse; bei DNS-Befunden Domain oder öffentliche IP."
    },
    {
     "type": "object",
     "required": [
      "adresse"
     ],
     "properties": {
      "adresse": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      },
      "selektor": {
       "type": "string",
       "maxLength": 240,
       "minLength": 1,
       "description": "CSS-Selektor: genau ein Objekt, sonst erster Treffer des Objektfilters."
      },
      "vergleich": {
       "type": "string",
       "maxLength": 2048,
       "description": "Öffentliche Vergleichsadresse für Link-, Sitemap- oder Sprachbefunde."
      },
      "user_agent": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_-]{1,80}$"
      },
      "dkim_selektor": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_-]{1,63}$"
      }
     },
     "additionalProperties": false
    }
   ]
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tempo-halowerk-script-time-to-first-paint-checker-af852d80/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from tempo.halowerk.com](https://www.zero.xyz/host/tempo.halowerk.com/llms.txt)