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

78%

Does it follow best practices?

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Securityby

High

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Fix and improve this skill with Tessl

tessl review fix ./youtube-downloader/SKILL.md

Quality

Content

63%Weight 40%Scale 1-5

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

A thorough, actionable skill body with good validation and feedback loops, undermined by significant duplication of the SOP across the body and the orphaned internal-sop.md reference, plus inlining of material that should live in the bundle files.

Suggestions

Link references/internal-sop.md from the body and remove the inlined Reliable Download SOP / Agent Execution Checklist duplicate of it, keeping one canonical checklist.

Move the detailed HLS Stream Downloads section into a references/hls-streams.md file, leaving a concise overview plus a one-level-deep link in SKILL.md.

Trim concept explanations Claude already knows (master vs rendition playlists, the per-flag ffmpeg parameter glossary) to tighten the body.

Dimension	Reasoning	Score
Conciseness	Core guidance is actionable, but the Reliable Download SOP (lines 71-84) and Agent Execution Checklist (86-102) duplicate each other and the bundled references/internal-sop.md, and the HLS section explains concepts (master vs rendition playlists, ffmpeg flags) Claude already knows.	3 / 5
Actionability	Provides concrete, mostly copy-paste-ready commands (yt-dlp format strings, ffmpeg -headers invocations, scripts/download_video.py with a full argument list, ffprobe verification) covering common cases, with minor placeholder gaps (<YTDLP_PYTHON>, VIDEO_URL).	4 / 5
Workflow Clarity	Clear numbered sequences with explicit validation checkpoints (verify formats 137/271/313, ffprobe quality) and feedback loops (retry on 403/fragments, restart PO token, fallback to WPC); mild friction from the duplicated SOP/checklist sections.	4 / 5
Progressive Disclosure	po-token-setup.md and download_video.py are clearly signaled, but references/internal-sop.md is orphaned (never linked while its content is inlined), and large blocks (SOP, full HLS guide, troubleshooting) are inlined that belong in the existing reference files.	3 / 5
	Total	14 / 20 Passed

Description

92%Weight 40%Scale 1-5

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

A strong, specific description that concretely states capabilities and gives explicit, natural trigger guidance with distinctive error-signature triggers. Only minor gap is the absence of common synonyms (MP3, save video, quality levels).

Dimension	Reasoning	Score
Specificity	Lists multiple concrete actions (download YouTube videos, download HLS/m3u8 streams, extract audio, handle protected streams with auth headers, troubleshoot nsig/403/cookie failures) with specific tools (yt-dlp, ffmpeg) and platforms (Mux, Vimeo), giving comprehensive coverage.	5 / 5
Completeness	Explicitly answers both what (download YouTube/HLS, extract audio, handle protected streams, troubleshoot) and when via a concrete "Use this skill when users request..." clause with specific trigger phrases.	5 / 5
Trigger Term Quality	Good natural keyword coverage ("downloading videos", "extracting audio", "403 errors", "cookie extraction problems", "HLS streams (m3u8)") but missing common synonyms users would say like "save video", "MP3", or quality terms (1080p/4K).	4 / 5
Distinctiveness Conflict Risk	Clear niche (YouTube + HLS streaming downloads via yt-dlp/ffmpeg) anchored by distinctive troubleshooting signatures (nsig, 403, cookie extraction), giving minimal overlap risk with unrelated skills.	5 / 5
	Total	19 / 20 Passed

Validation

87%

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 — 14 / 16 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
relative_links	Relative link issues: 2 missing	Warning

	Total	14 / 16 Passed

Repository: daymade/claude-code-skills
Path: youtube-downloader/SKILL.md
Commit: b8556f2

Reviewed: 3 days ago

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