Youtube Summarizer

Overview

This skill downloads the auto-generated subtitle track from any YouTube video using yt-dlp, parses it into clean text, and produces a well-structured markdown summary with:

• High-level TL;DR
• Section-by-section breakdown of the content
• Key takeaways / actionable insights
• A links table for every resource mentioned in the video

When to Use

Invoke this skill whenever the user:

• Shares a YouTube URL and asks for a "summary", "overview", "transcript", "recap", or "what is this about"
• Wants to extract key points or learn from a video without watching it
• Wants to catch up on a video and get helpful links to resources mentioned

Workflow

Step 1 — Ensure yt-dlp is available

if [ ! -x /tmp/yt-dlp ]; then
  curl -sL https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -o /tmp/yt-dlp && chmod +x /tmp/yt-dlp
fi
/tmp/yt-dlp --version

yt-dlp is downloaded to /tmp/yt-dlp on first use. It is ~10 MB and takes about 5 seconds.

Step 2 — Download the subtitle track

/tmp/yt-dlp \
  --write-auto-sub \
  --sub-lang en \
  --skip-download \
  --output /tmp/ytvideo \
  "<YOUTUBE_URL>"

This produces /tmp/ytvideo.en.vtt. If auto-subs are unavailable try --write-sub as fallback.

Step 3 — Parse the VTT into clean transcript text

Run this Python snippet to strip timestamps, HTML tags, and duplicate lines:

import re

with open('/tmp/ytvideo.en.vtt', 'r') as f:
    content = f.read()

lines = content.split('\n')
text_lines = []
seen = set()

for line in lines:
    line = line.strip()
    # Skip VTT metadata and timestamp lines
    if (re.match(r'^\d{2}:\d{2}', line)
            or line in ('WEBVTT', '')
            or line.startswith(('Kind:', 'Language:'))):
        continue
    # Strip inline HTML tags (e.g., <c>, <00:01:23.000>)
    clean = re.sub(r'<[^>]+>', '', line).strip()
    if clean and clean not in seen:
        seen.add(clean)
        text_lines.append(clean)

transcript = '\n'.join(text_lines)
print(transcript)

Save the output to /tmp/transcript_clean.txt for use in the next step.

Step 4 — Extract video metadata (title + description)

curl -sL "https://www.youtube.com/watch?v=<VIDEO_ID>" | python3 -c "
import sys, re
html = sys.stdin.read()
t = re.search(r'\"title\":\{\"runs\":\[\{\"text\":\"(.*?)\"', html)
d = re.search(r'\"shortDescription\":\"(.*?)(?<!\\\\)\"', html, re.DOTALL)
if t: print('TITLE:', t.group(1))
if d: print('DESC:', d.group(1).replace('\\\\n','\n')[:1500])
"

This captures the title and description (which usually lists referenced links and channels).

Step 5 — Produce the summary

With the full transcript text in context, write the summary using the Output Format below. Read the transcript carefully — do not make up content. Pull real section titles, timestamps, speaker names, and resources directly from the text.

Output Format

Structure every summary exactly like this:

## [Video Title]

**Video:** [Title](URL) by [Author/Channel]

---

### What It's About

1–3 sentence executive summary of the video's core subject and value.

---

### [Section Name] (~timestamp if available)

Concise description of what this section covers. Include any specific tools, techniques, 
commands, costs, or results mentioned by the speaker. Keep each section 2–5 sentences.

[Repeat for all major sections / use cases / topics]

---

### Key Takeaways

- Bullet 1
- Bullet 2
- Bullet 3
...

---

### Resources & Links

| Resource | Link |
|---|---|
| [Name] | [url] |
...

Rules:

• Use the real section/chapter names from the video, not generic headings
• Include approximate timestamps in parentheses when they appear in the transcript
• For each resource explicitly mentioned in the video (tools, repos, websites, courses), add it to the links table
• Keep the tone factual and informative — no hype
• If the video is technical, preserve specific commands, file names, config snippets
• If no transcript is available (private/geo-blocked video), say so clearly and explain the limitation

Common Issues & Fixes

Example Invocations

Summarize this video: https://youtu.be/6KB73J01fGw

What is this YouTube video about? https://www.youtube.com/watch?v=dQw4w9WgXcQ

Give me the key takeaways from https://youtu.be/ABC123XYZ

Getting Started

When the user provides a YouTube URL:

1. Run the yt-dlp install check (Step 1)
2. Download subtitles (Step 2)
3. Parse the VTT (Step 3)
4. Fetch title + description (Step 4)
5. Write the full summary using the Output Format (Step 5)

Do all heavy lifting (transcript fetch + parse) in Bash/Python tool calls before writing the summary. Never guess the video's content — always read the actual transcript.