youtube-downloader

Download YouTube videos and HLS streams (m3u8) from platforms like Mux, Vimeo, etc. using yt-dlp and ffmpeg. Use this skill when users request downloading videos, extracting audio, handling protected streams with authentication headers, or troubleshooting download issues like nsig extraction failures, 403 errors, or cookie extraction problems.

Quality

81%

Does it follow best practices?

Impact

Pending

No eval scenarios have been run

Securityby

Advisory

Suggest reviewing before use

Quality

Discovery

100%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

This is an excellent skill description that clearly communicates specific capabilities, includes rich natural trigger terms, explicitly states both what the skill does and when to use it, and occupies a distinct niche. It uses proper third-person voice and avoids vague language or buzzwords.

Dimension	Reasoning	Score
Specificity	Lists multiple specific concrete actions: downloading YouTube videos, downloading HLS streams (m3u8), extracting audio, handling protected streams with authentication headers, and troubleshooting specific issues like nsig extraction failures, 403 errors, and cookie extraction problems.	3 / 3
Completeness	Clearly answers both 'what' (download YouTube videos and HLS streams using yt-dlp and ffmpeg) and 'when' (explicit 'Use this skill when...' clause covering downloading videos, extracting audio, handling protected streams, and troubleshooting specific download issues).	3 / 3
Trigger Term Quality	Excellent coverage of natural terms users would say: 'YouTube', 'download videos', 'HLS streams', 'm3u8', 'Mux', 'Vimeo', 'yt-dlp', 'ffmpeg', 'extracting audio', '403 errors', 'cookie extraction', 'authentication headers'. These are all terms a user would naturally use when seeking help with video downloading.	3 / 3
Distinctiveness Conflict Risk	Highly distinctive with a clear niche around video downloading and streaming. The specific tools (yt-dlp, ffmpeg), platforms (YouTube, Mux, Vimeo), protocols (HLS, m3u8), and error types (nsig, 403, cookies) make it very unlikely to conflict with other skills.	3 / 3
	Total	12 / 12 Passed

Implementation

62%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

This skill is highly actionable with excellent workflow clarity, providing executable commands, clear error-recovery loops, and a well-structured troubleshooting reference. However, it is significantly too verbose — containing redundant sections (SOP, checklist, and user experience sections overlap heavily), unnecessary explanations of concepts Claude already knows (ffmpeg flags, HLS basics, codec descriptions), and inline content that should be in reference files. Trimming redundancy and moving detailed sections to referenced files would dramatically improve token efficiency.

Suggestions

Consolidate the 'Reliable Download SOP', 'Agent Execution Checklist', and 'Non-Technical User Experience' sections into a single concise workflow — they currently repeat the same logic (e.g., 403 handling, cookie usage, PO token fallback) in three places.

Remove explanations of things Claude already knows: ffmpeg parameter descriptions (-crf, -preset, -c:v libx264), what HLS/m3u8 is, what AAC is, and the 'When to Use This Skill' section (this belongs in frontmatter, not body).

Move the HLS stream download section and the detailed troubleshooting reference into separate files (e.g., references/hls-downloads.md, references/troubleshooting.md) and link to them from the main SKILL.md.

Remove the WebM-to-MP4 parameter explanations and the 'Performance Tips' section — Claude knows ffmpeg well and these add tokens without adding value.

Dimension	Reasoning	Score
Conciseness	The skill is extremely verbose at ~350+ lines. It explains concepts Claude already knows (what HLS is, what ffmpeg parameters do, what AAC is), includes redundant sections (the 'When to Use This Skill' section restates the description), explains ffmpeg flags like -crf and -preset that Claude knows well, and has significant overlap between the 'Non-Technical User Experience', 'Agent Execution Checklist', and 'Reliable Download SOP' sections.	1 / 3
Actionability	The skill provides fully executable, copy-paste-ready commands throughout — yt-dlp format checks, download commands with specific flags, ffmpeg conversion commands, and a bundled script with complete argument documentation. Troubleshooting sections pair specific error messages with concrete solutions.	3 / 3
Workflow Clarity	Multi-step workflows are clearly sequenced with explicit validation checkpoints: check formats → install PO token provider → verify formats again → download → verify with ffprobe. The SOP includes feedback loops (retry with cookies if 403, fall back to WPC if Docker fails, restart provider on timeout). HLS workflow has clear step-by-step with verification.	3 / 3
Progressive Disclosure	The skill references `references/po-token-setup.md` and `scripts/download_video.py` appropriately, but the main file itself is monolithic with too much inline content. The HLS section, WebM conversion details, ffmpeg parameter explanations, and the extensive troubleshooting could be split into separate reference files. The quality expectations table and common tasks are good inline content, but the overall document is too long for a single SKILL.md.	2 / 3
	Total	9 / 12 Passed

Validation

90%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 10 / 11 Passed

Validation for skill structure

Criteria	Description	Result
skill_md_line_count	SKILL.md is long (509 lines); consider splitting into references/ and linking	Warning

	Total	10 / 11 Passed

Repository: daymade/claude-code-skills
Commit: b2003d6

Reviewed: 2 days ago

Table of Contents

Discovery Implementation Validation

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