Fixing Broken Links

Scan a file (or set of files) for URLs, test every link, and fix any that are broken.

Workflow

1. Extract All Links

Read the target file(s) and collect every URL:

• Markdown links: [text](url)
• Bare URLs: https://...
• HTML href and src attributes
• Reference-style link definitions: [id]: url
• Local relative paths: ./path/to/file, resources/foo/SKILL.md

2. Test Each Link

For external URLs:

• Use curl -sL -o /dev/null -w "%{http_code}" --max-time 10 "<url>" to get the HTTP status code
• Batch independent checks for speed (run multiple curl commands in parallel or in quick succession)
• Classify results:
  • 200–299 → OK
  • 301/302 → OK but note the redirect target
  • 403 → Might be valid (some sites block curl); try with a browser user-agent header
  • 404 → Broken
  • 429 → Rate limited; retry once after a short pause
  • 000 or timeout → Retry once; if still failing, mark as unreachable

For local file paths:

• Check if the file exists on disk with [ -f "path" ]
• If it's a relative path, resolve it from the file's directory

3. Fix Broken Links

For each broken link:

1. Search the web for the correct/current URL (the resource may have moved)
2. If found, replace the old URL with the new one
3. If the resource no longer exists, note it and either:
   • Remove the link and leave the text
   • Comment it out with a note
   • Replace with an archived version (web.archive.org)

4. Report

Produce a summary table:

| URL | Status | Action |
|-----|--------|--------|
| https://example.com/page | 200 | OK |
| https://old.example.com/moved | 404 → 301 | Updated to https://new.example.com/page |
| ./docs/missing.md | MISSING | Removed link |

Tips

• For large files with many links, batch curl calls to avoid slowdowns
• Some sites (GitHub, npm) rate-limit aggressively — space out requests
• Always re-read the file after making changes to confirm replacements didn't break formatting
• For Markdown files, verify link syntax is preserved: [text](url) not [text]( url ) (no extra spaces)