Conciseness

The body is mostly dense with genuinely non-obvious operational knowledge (PO token providers, format IDs 137/271/313, nsig failures, client quirks), but it inlines a 'Reliable Download SOP (Internal)' section that near-verbatim duplicates references/internal-sop.md, the 'Agent Execution Checklist' repeats the Troubleshooting section's cause/solution pairs, and well-known ffmpeg flags (libx264, crf ranges) are explained. It fits 'mostly efficient but includes some unnecessary explanation or could be tightened' rather than the 2 anchor's several padded sections, and the duplication is more than the 4 anchor's minor trims.

Actionability

Nearly all guidance is copy-paste executable: complete yt-dlp and ffmpeg commands with format strings and header patterns, a full argument reference for scripts/download_video.py, and concrete verification commands (yt-dlp -F, ffprobe). The only placeholder (<YTDLP_PYTHON>) is explicitly resolved in-line by instruction, so this matches the fully executable anchor rather than the 4 anchor's 'minor gaps'.

Workflow Clarity

Workflows are clearly sequenced (default user flow 1-5, SOP steps 1-8 with fallback branches like Docker bgutil to browser WPC, HLS steps 1-3) and include explicit validation checkpoints (re-run yt-dlp -F and look for formats 137/271/313, ffprobe resolution check, --info metadata confirmation), retry feedback loops in every troubleshooting entry, and a dedicated checklist. This matches the anchor requiring validation steps, error-recovery loops, and checklists rather than the 4 anchor's 'minor validation gaps'.

Progressive Disclosure

The bundle is well-structured: references/po-token-setup.md and references/internal-sop.md exist, are one level deep, and are clearly signaled with purpose statements ('Read it first when a download fails for no obvious reason'), and the script is documented with its full argument list. However, the SOP content that lives in references/internal-sop.md is duplicated inline in the body, and the ~130-line HLS section is bulk content that belongs in a reference file, which are the 'minor organization gaps' of the 4 anchor rather than the clean split of a 5.

Specificity

The description lists multiple concrete actions ("Download YouTube videos and HLS streams (m3u8)", "extracting audio", "handling protected streams with authentication headers", troubleshooting "nsig extraction failures, 403 errors, or cookie extraction problems") with named tools (yt-dlp, ffmpeg). It matches the anchor for multiple specific concrete actions with comprehensive coverage; a 4 would require minor gaps in coverage, which are not evident here.

Completeness

It clearly answers both what ("Download YouTube videos and HLS streams (m3u8)... using yt-dlp and ffmpeg") and when ("Use this skill when users request downloading videos, extracting audio, handling protected streams... or troubleshooting download issues...") with concrete trigger phrases. This matches the anchor-5 example structure exactly; a 4 would require the 'when' clause to be less explicit or specific.

Trigger Term Quality

Natural phrases like "downloading videos", "extracting audio", "403 errors", and "m3u8" are present, giving good keyword coverage. A few natural terms users would say are missing (e.g., "save video", "rip", "MP3", "convert to MP4"), so it falls just short of the comprehensive synonym coverage of a 5.

Distinctiveness Conflict Risk

It occupies a clear niche (yt-dlp/ffmpeg-based video and HLS stream downloading, including named platforms Mux and Vimeo) with distinct trigger terms (nsig extraction, m3u8, PO-token-era failure modes). Conflict risk with other skills is minimal; a 4 would require noticeable overlap with closely related skills, which is not the case.