YouTube Transcript Extraction

Extract subtitles/transcripts from a YouTube video URL and save them as a local file.

Input YouTube URL: $ARGUMENTS

Step 1: Verify URL

Confirm the input is a valid YouTube URL (supports youtube.com/watch?v=, youtu.be/, and youtube.com/shorts/ formats). If no URL is provided via arguments, check the conversation context for a YouTube link.

Step 2: CLI Quick Extraction (Priority Attempt)

Use command-line tools to quickly extract subtitles.

2.1 Check Tool Availability

Execute which yt-dlp.

• If yt-dlp is found, proceed to 2.2.
• If yt-dlp is not found, skip to Step 3.

2.2 Get Video Title

yt-dlp --cookies-from-browser=chrome --get-title "[VIDEO_URL]"

• Tip: Always add --cookies-from-browser to avoid sign-in restrictions. Default to chrome.
• If it fails with a browser error (e.g., "Could not open Chrome"), ask the user to specify their available browser (e.g., firefox, safari, edge) and retry.

2.3 Download Subtitles

yt-dlp --cookies-from-browser=chrome --write-auto-sub --write-sub --sub-lang zh-Hans,zh-Hant,en --skip-download --output "<Video Title>.%(ext)s" "[VIDEO_URL]"

2.4 Convert to Plain Text

yt-dlp saves subtitles as .vtt or .srt files. Convert the downloaded file to plain Timestamp Text format:

1. Read the downloaded subtitle file (.vtt or .srt).
2. Strip VTT/SRT headers, styling tags, and duplicate lines.
3. Save as <Video Title>.txt with one Timestamp Text entry per line.

2.5 Verify Results

• Exit code 0: Convert and save the subtitle file, then report completion.
• Exit code non-0:
  • If error is related to browser/cookies, ask user for correct browser and retry.
  • If other errors (e.g., video unavailable), proceed to Step 3.

Step 3: Browser Automation (Fallback)

When the CLI method fails or yt-dlp is missing, use Chrome DevTools MCP to extract subtitles via browser UI automation.