# AgentShelf CSS track[src] Extractor

> AgentShelf CSS track[src] Extractor is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).

Extracts text track source URLs (track[src] attributes) from HTML or a public web page URL, returning all values found in <track> elements.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/css-track-src?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-css-track-src-extractor-d9fa0065
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_teJGokXD2Y9xouhlrsjBC

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 agentshelf-css-track-src-extractor-d9fa0065 -d '<json body>'
```

Example prompt: Can you pull out all the text track source URLs (like subtitle or caption file links) from this video page? The URL is https://example.com/video/episode-1

## When to prefer this

Use this endpoint when you need to extract text track (subtitle, caption, chapter, or description) source file URLs from a public web page or a known HTML fragment. It is SSRF-safe, making it suitable for agent pipelines where arbitrary URLs are processed. Prefer the unpaid sandbox at POST /v1/sandbox/css-track-src for testing. Choose this over a general HTML scraper when you specifically need track[src] values for media accessibility or subtitle pipeline work.

## Known failure modes

- URL is unreachable or returns non-200 status — extraction fails with an error
- Provided HTML exceeds 200,000 character limit — request rejected
- URL blocked due to SSRF protection (private/internal IP ranges) — returns SSRF error
- No track elements found in the HTML — returns empty list
- Malformed HTML provided — parser may return incomplete or empty results
- URL string shorter than 8 characters or HTML shorter than 1 character — validation error

## How this service works

Call when an agent needs text track sources via track[src] from a public page or HTML (SSRF-safe). Exact $0.005 USDC. Prefer unpaid POST /v1/sandbox/css-track-src first.

## Output

Returns a list of all src attribute values found on <track> elements within the fetched or provided HTML, typically pointing to WebVTT or timed text files used for subtitles, captions, chapters, or audio descriptions.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048,
   "minLength": 8,
   "description": "Public page to fetch. The selector or profile is fixed by the SKU. Provide url or html."
  },
  "html": {
   "type": "string",
   "examples": [
    "<!doctype html><html lang=\"en\"><head><title>Hello</title>\n<meta charset=\"utf-8\"><meta name=\"description\" content=\"Desc\">\n<link rel=\"canonical\" href=\"https://example.com/\"><link rel=\"icon\" href=\"/favicon.ico\">\n</head><body><h1>Hello</h1><a href=\"https://example.com/a\">A</a></body></html>"
   ],
   "maxLength": 200000,
   "minLength": 1,
   "description": "HTML to extract from locally. Provide html or url. When both are set, html is used."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-css-track-src-extractor-d9fa0065/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)