Create llms-txt-validation.js

[chr156r33n]

Added llms-txt-valid for custom metrics - wasn't sure of where best to include, so created a new file.

Adding the following:

Fetches /llms.txt and returns a simple validity flag (1 or 0). It checks that the response:

• Succeeds (HTTP 2xx)
• Has a Content-Type of text/plain
• Contains balanced Markdown code fences (…)
• Has matching counts of [ vs. ] and ( vs. )

If any check fails, it returns 0; otherwise it returns 1.

Expected test results:

https://llmstxt.org/llms.txt - Should pass "llms-txt-valid": 1
https://www.twitch.tv/llms.txt - Should fail, incorrect mime type "llms-txt-valid": 0
https://www.chris-green.net/llms.txt - Should fail, 404 "llms-txt-valid": 0
https://rgarttherapy.co.uk/llms.txt - Invalid file "llms-txt-valid": 0

---

Test websites:

• https://llmstxt.org/
• https://www.twitch.tv/
• https://www.chris-green.net/
• https://rgarttherapy.co.uk/

[github-actions]

https://almanac.httparchive.org/en/2022/

WPT result details

Changed custom metrics values:

{
  "_llms_txt_validation": {
    "valid": false,
    "message": 404,
    "error": "Non OK status code"
  }
}

https://llmstxt.org

WPT result details

Changed custom metrics values:

{
  "_llms_txt_validation": {
    "valid": true
  }
}

https://www.twitch.tv

WPT result details

Changed custom metrics values:

{
  "_llms_txt_validation": {
    "valid": false,
    "message": "text/html",
    "error": "Invalid content type"
  }
}

https://www.chris-green.net

WPT result details

Changed custom metrics values:

{
  "_llms_txt_validation": {
    "valid": false,
    "message": 404,
    "error": "Non OK status code"
  }
}

https://rgarttherapy.co.uk

WPT result details

Changed custom metrics values:

{
  "_llms_txt_validation": {
    "valid": true,
    "error": "Invalid markdown: Unmatched braces"
  }
}