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 skills add Casper-Studios/casper-marketplace --skill youtube-toolsgit clone --depth 1 https://github.com/Casper-Studios/casper-marketplaceWrote 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/casper-studios/casper-marketplace/youtube-tools)<a href="https://agentmods.dev/skills/casper-studios/casper-marketplace/youtube-tools"><img src="https://agentmods.dev/badge/skills/casper-studios/casper-marketplace/youtube-tools/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/casper-studios/casper-marketplace/youtube-tools"><img src="https://agentmods.dev/badge/skills/casper-studios/casper-marketplace/youtube-tools.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00078 | $0.01721 |
| Opus 5 | $0.00039 | $0.00860 |
| Sonnet 5 | $0.00016 | $0.00344 |
| Haiku 4.5 | $0.00008 | $0.00172 |
Grade B, and why
youtube-tools 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 11d 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 install ffmpeg How it starts
The opening of the file, as written. The whole thing — 225 lines — stays where its author put it; the contents beside it link to each section on GitHub.
YouTube Tools (yt-dlp)
Overview
Free, local YouTube operations using yt-dlp. No API keys required, no per-video costs. Works offline after installation.
When to Use This vs Apify
┌─────────────────────────────────────────────────────────────────┐
│ DECISION: YouTube Tools (yt-dlp) vs Apify │
├─────────────────────────────────────────────────────────────────┤
│ │
│ Use youtube-tools (FREE) when: │
│ ├── Downloading videos to local storage │
│ ├── Extracting transcripts/subtitles │
│ ├── Getting video metadata (title, duration, views, etc.) │
│ ├── Bulk downloading playlists or channels │
│ ├── Converting to audio-only (MP3) │
│ └── You want zero API costs │
│ │
│ Use apify-scrapers when: │
│ ├── Scraping YouTube SEARCH results │
│ ├── Getting comments at scale │
│ ├── Channel analytics and statistics │
│ ├── Trending video discovery │
│ └── You need cloud-based processing │
│ │
└─────────────────────────────────────────────────────────────────┘
Quick Decision Tree
What do you need?
│
├── Download video(s)
│ ├── Single video → scripts/download_video.py URL
│ ├── Multiple videos → scripts/download_video.py --urls-file list.txt
│ ├── Playlist → scripts/download_video.py "playlist_url"
│ ├── Audio only → scripts/download_video.py URL --audio-only
│ └── Specific quality → scripts/download_video.py URL --quality 720p
│
├── Get transcript/subtitles
│ ├── Auto-generated captions → scripts/get_transcript.py URL
│ ├── Manual subtitles → scripts/get_transcript.py URL --manual-only
│ ├── Specific language → scripts/get_transcript.py URL --lang es
│ └── All available → scripts/get_transcript.py URL --all-langs
│
├── Get video metadata
│ ├── Single video → scripts/get_video_info.py URL
│ ├── Multiple videos → scripts/get_video_info.py --urls-file list.txt
│ └── Playlist info → scripts/get_video_info.py "playlist_url"
│
└── Advanced
├── Age-restricted → scripts/download_video.py URL --cookies-from-browser chrome
├── Private videos → Requires authentication (see references/yt-dlp-guide.md)
└── Live streams → scripts/download_video.py URL --live-from-start
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 11d ago First seen · 225 lines · 78 tokens per session scan B b855f94621c8
youtube-tools is a skill published in the GitHub repository Casper-Studios/casper-marketplace (12 stars, last pushed 6d ago), licensed MPL-2.0. It adds 78 tokens to every session and 1,721 once invoked, about $0.0004 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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