youtube-transcribe-skill

# 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

```bash
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

```bash
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.

### 3.1 Check Tool Availability

Check if Chrome DevTools MCP tools are available (look for tools matching `chrome__new_page` or similar).

If Chrome DevTools MCP is **not** available and `yt-dlp` was **not** found in Step 2, stop and notify the user: "Unable to proceed. Please either install `yt-dlp` (for fast CLI extraction) or configure Chrome DevTools MCP (for browser automation)."

### 3.2 Open Video Page

Use Chrome DevTools MCP `new_page` to open the video URL.

### 3.3 Analyze Page State

Use Chrome DevTools MCP `take_snapshot` to read the page accessibility tree.

### 3.4 Expand Video Description

The "Show transcript" button is usually hidden within the collapsed description area.

1. Search the snapshot for a button labeled **"...more"**, **"...更多"**, or **"Show more"** (in the description block below the video title).
2. Use Chrome DevTools MCP `click` to click that button.

### 3.5 Open Transcript Panel

1. Use Chrome DevTools MCP `take_snapshot` to get the updated UI.
2. Search for a button labeled **"Show transcript"**, **"显示转录稿"**, or **"内容转文字"**.
3. Use Chrome DevTools MCP `click` to click that button.
4. If the button is not found, the video may not have a transcript available — notify the user and stop.

### 3.6 Extract Content via DOM

Directly reading the accessibility tree for long transcript lists is slow and token-heavy. Use Chrome DevTools MCP `evaluate_script` to run this JavaScript instead:

```javascript
() => {
  const segments = document.querySelectorAll("ytd-transcript-segment-renderer");
  if (!segments.length) return "BUFFERING";
  return Array.from(segments)
    .map((seg) => {
      const time = seg.querySelector(".segment-timestamp")?.innerText.trim();
      const text = seg.querySelector(".segment-text")?.innerText.trim();
      return `${time} ${text}`;
    })
    .join("\n");
};
```

If it returns `"BUFFERING"`, wait a few seconds and retry (up to 3 attempts).

### 3.7 Save and Cleanup

1. Save the extracted text as `<Video Title>.txt`.
2. Use Chrome DevTools MCP `close_page` to release resources.

## Output Requirements

- Save the subtitle file to the current working directory.
- Filename format: `<Video Title>.txt`
- File content format: Each line should be `Timestamp Subtitle Text`.
- Report upon completion: file path, subtitle language, and total number of lines.