Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/cdeistopened/skill-stack/youtube-downloadernpx skills add cdeistopened/skill-stack --skill youtube-downloadergit clone --depth 1 https://github.com/cdeistopened/skill-stackWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/cdeistopened/skill-stack/youtube-downloader)<a href="https://agentmods.dev/skills/cdeistopened/skill-stack/youtube-downloader"><img src="https://agentmods.dev/badge/skills/cdeistopened/skill-stack/youtube-downloader.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00048 | $0.02803 |
| Opus 5 | $0.00024 | $0.01401 |
| Sonnet 5 | $0.00010 | $0.00561 |
| Haiku 4.5 | $0.00005 | $0.00280 |
Grade B, and why
youtube-downloader scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Asks for rootmediumPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
sudo apt update && sudo apt install -y yt-dlp How it starts
The opening of the file, as written. The whole thing — 349 lines — stays where its author put it; the contents beside it link to each section on GitHub.
YouTube Transcript Downloader
This skill helps download transcripts (subtitles/captions) from YouTube videos using yt-dlp.
When to Use This Skill
Activate this skill when the user:
- Provides a YouTube URL and wants the transcript
- Asks to "download transcript from YouTube"
- Wants to "get captions" or "get subtitles" from a video
- Asks to "transcribe a YouTube video"
- Needs text content from a YouTube video
How It Works
Default Workflow:
- Check if yt-dlp is installed - install if needed
- Try manual subtitles first (
--write-sub) - highest quality, human-created - Fallback to auto-generated (
--write-auto-sub) - usually available - Convert to plain text - deduplicate and clean up VTT format
- Save to output directory as a markdown file with filename based on video title
- Automatically polish - remove filler words, fix grammar, add section headers, maintain 100% fidelity
- Confirm the download and show the user where the file is saved
Installation Check
IMPORTANT: Always check if yt-dlp is installed first:
which yt-dlp || command -v yt-dlp
If Not Installed
Attempt automatic installation based on the system:
macOS (Homebrew):
brew install yt-dlp
Linux (apt/Debian/Ubuntu):
sudo apt update && sudo apt install -y yt-dlp
Alternative (pip - works on all systems):
pip3 install yt-dlp
# or
python3 -m pip install yt-dlp
If installation fails: Inform the user they need to install yt-dlp manually and provide them with installation instructions from https://github.com/yt-dlp/yt-dlp#installation
Check Available Subtitles
ALWAYS do this first before attempting to download:
yt-dlp --list-subs "YOUTUBE_URL"
This shows what subtitle types are available without downloading anything. Look for:
- Manual subtitles (better quality)
- Auto-generated subtitles (usually available)
- Available languages
Download Strategy
Option 1: Manual Subtitles (Preferred)
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 349 lines · 48 tokens per session scan B 3f8aa25d8bc4
youtube-downloader is a skill published in the GitHub repository cdeistopened/skill-stack (27 stars, last pushed 1mo ago), licensed MIT. It adds 48 tokens to every session and 2,803 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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