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.
84
81%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
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 defines its scope, lists concrete actions and tools, includes a comprehensive 'Use when' clause with specific trigger scenarios, and uses highly distinctive terminology. It covers both common use cases (downloading videos, extracting audio) and edge cases (troubleshooting specific errors), making it easy for Claude to select appropriately.
| 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', 'authentication headers', '403 errors', 'cookie extraction'. These are highly natural keywords a user would use when seeking help with video downloading. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive with a clear niche around video downloading, specific tools (yt-dlp, ffmpeg), specific platforms (YouTube, Mux, Vimeo), and specific error types (nsig extraction, 403 errors, cookie extraction). 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.
The skill is highly actionable with excellent workflow clarity, providing concrete commands, clear error recovery paths, and systematic troubleshooting. However, it is significantly too verbose — it explains things Claude already knows (ffmpeg parameters, what HLS is), has redundant sections (SOP, checklist, and user experience sections overlap considerably), and inlines too much content that should be in reference files. The token cost is high relative to the unique information density.
Suggestions
Eliminate redundancy between 'Non-Technical User Experience', 'Reliable Download SOP', and 'Agent Execution Checklist' — merge into a single concise workflow with internal notes inline rather than three overlapping sections.
Remove explanations of concepts Claude already knows: ffmpeg parameter descriptions (CRF, preset, codec explanations), what HLS/m3u8 is, what a master vs rendition playlist is, and performance tips like '10-15x realtime speed'.
Move the HLS stream section, detailed troubleshooting reference, and the full script argument list into separate reference files, keeping only a brief summary and link in the main SKILL.md.
Remove the 'When to Use This Skill' section entirely — this duplicates the YAML description and wastes tokens on information the routing system already handles.
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is extremely verbose at ~300+ lines. It explains concepts Claude already knows (what HLS is, what ffmpeg parameters do, what PDF-like 'Parameters explained' sections), includes redundant sections (the 'When to Use This Skill' section restates the description), and has significant overlap between the 'Non-Technical User Experience', 'Agent Execution Checklist', and 'Reliable Download SOP' sections. The ffmpeg parameter explanations and WebM conversion parameter breakdown are unnecessary for Claude. | 1 / 3 |
Actionability | The skill provides fully executable, copy-paste ready commands throughout — yt-dlp format checks, download commands, ffmpeg conversions, HLS downloads with headers, and a bundled script with complete argument documentation. Code examples are concrete and specific with real flag combinations. | 3 / 3 |
Workflow Clarity | Multi-step workflows are clearly sequenced with explicit validation checkpoints (check formats after PO token install, verify download quality with ffprobe, retry logic for 403s and PO token failures). The SOP includes clear error recovery paths (Docker fails → WPC fallback, 403 → cookie retry → web_safari). The troubleshooting section maps symptoms to causes to solutions systematically. | 3 / 3 |
Progressive Disclosure | There is one reference to an external file (references/po-token-setup.md) and links to external docs, which is good. However, the main file is monolithic with extensive inline content that could be split — the HLS section, troubleshooting reference, and detailed ffmpeg conversion guide could each be separate reference files. The bundled script argument list is very long and could be in a separate reference. | 2 / 3 |
Total | 9 / 12 Passed |
Validation
90%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
80e94fd
- Reviewed
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