yt-dlp

yt-dlp

CLI skill for yt-dlp: read-only URL probes, caption/transcript extraction, and optional media download. Follow the transcript-first protocol before any download.

Scope: Supported video/audio hosts via yt-dlp, user-owned cookie files, playlist metadata, and local output under an explicit directory. NOT for: static page fetch (use Fetch MCP or curl), broad multi-source research (research), ffmpeg transform recipes (ffmpeg), or bypassing platform Terms of Service.

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Canonical Vocabulary

Term	Meaning	NOT
probe	Read-only metadata via --dump-json; no media write	download
transcript	Captions/subtitles to text files; prefer over full download	audio rip by default
download	Persist media bytes after probe + user approval	silent bulk grab
playlist	Multi-entry URL; enumerate before selective download	blind full-playlist download
cookies	User-owned Netscape cookie file passed with --cookies	committed or skill-bundled secrets
doctor	Preflight JSON report for binary, version, ffmpeg	live URL smoke
format id	yt-dlp format_id from probe (e.g. 251, 137+140)	guessed extension
manual sub	Creator-uploaded captions	auto-generated only
auto sub	Platform-generated captions	guaranteed accuracy

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Dispatch

$ARGUMENTS	Mode	Action
probe <url> / metadata <url> / info <url>	Probe	Run bundled probe_url.py; summarize title, id, duration, subs
transcript <url> / subs <url> / captions <url>	Transcript	Probe first; extract best available subtitles without video download
download <url> / fetch <url> / save <url>	Download	Probe first; confirm rights + format; download to explicit output dir
playlist <url>	Playlist	Probe with playlist allowed; list entries; selective download only with approval
cookies <path> / cookies check <path>	Cookies	Validate user-owned cookie file path; never copy into repo
doctor / preflight	Doctor	Run scripts/doctor.py --format json
Natural language: "what is this video", "get subtitles", "download this"	Auto	Map to probe → transcript → download per protocol below
(empty)	Help	Show modes, protocol, ethics pointer, and examples

Auto-Detection Heuristic

1. URL + words like subtitle, caption, transcript, CC → Transcript (still probe first).
2. URL + download, save, mp4, audio, rip → Download (still probe + approval first).
3. URL + playlist, channel list, all videos → Playlist.
4. Bare URL or "what is this link" → Probe.
5. Path ending in cookies.txt or mention of login/auth → Cookies guidance, then re-probe with --cookies.
6. Ambiguous → ask: metadata only, transcript, or download?

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Transcript-First Protocol

Run these stages in order. Do not skip probe. Do not download until transcript needs are ruled out or the user explicitly wants media files.

Stage 1 — Doctor (once per session or after errors)

uv run python scripts/doctor.py --format json

Stop on ok: false or any check with status: fail (missing yt-dlp binary).

Stage 2 — Probe (mandatory before transcript or download)

uv run python scripts/probe_url.py --url 'https://…' --format json

With user-owned cookies:

uv run python scripts/probe_url.py --url 'https://…' --cookies "$HOME/.config/yt-dlp/cookies.txt" --format json

Playlist URL (enumerate entries; pass --allow-playlist on probe):

uv run python scripts/probe_url.py --url 'https://www.youtube.com/playlist?list=PL…' --allow-playlist --format json

From probe JSON, report: id, title, duration, uploader, availability, subtitles / automatic_captions languages, and recommended format_id candidates. Load references/formats-and-quality.md when choosing formats.

Stage 3 — Transcript (preferred over download)

When subtitles exist, extract text without downloading video:

yt-dlp --skip-download --write-subs --write-auto-subs --sub-langs 'en.*,en' \
  --convert-subs srt --sub-format srt \
  -o '%(title).200B.%(ext)s' \
  --paths home:"$HOME/Downloads/yt-dlp/transcripts" \
  'URL'

Prefer manual subs over auto when both exist. Summarize path to .srt / .vtt and offer to strip timing lines for plain text. If no subs: say so and ask before download-for-transcription (higher cost, rights-sensitive).

Stage 4 — Download (explicit approval required)

Before running:

1. Confirm the user has rights to save the content (personal/archive/fair-use context per references/ethics-and-tos.md).
2. Confirm output directory (default: $HOME/Downloads/yt-dlp/media/).
3. Confirm format from probe (-f FORMAT or sensible default: bv*+ba/b).

mkdir -p "$HOME/Downloads/yt-dlp/media"
yt-dlp -f 'bv*+ba/b' \
  --paths home:"$HOME/Downloads/yt-dlp/media" \
  -o '%(playlist_index)s-%(title).200B.%(ext)s' \
  'URL'

Report output path, format id, file size, and whether ffmpeg merge ran.

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Mode Details

Probe mode

• Use bundled probe_url.py (wraps yt-dlp --dump-json --no-download).
• Read-only: no writes under cwd or repo.
• For age-gated or login-only content, stop and route to Cookies — do not guess credentials.

Transcript

• Never default to downloading video/audio for text needs.
• Use --skip-download always.
• If multiple languages, pick user-requested lang or en with fallback list from probe.

Download

• Single URL default: --no-playlist unless user asked for playlist.
• No bulk channel/archival without explicit scope confirmation.
• Do not embed cookies in commands in chat logs; reference $COOKIES env or user path only.

Playlist

1. Probe with playlist enabled:

uv run python scripts/probe_url.py --url 'PLAYLIST_URL' --allow-playlist --format json

2. Present numbered entries (index, title, duration).
3. Download selected indices only (--playlist-items 1,3,5) after approval — never blind full playlist.

Cookies

• User-owned cookie file only — path under user home or explicit user-provided path.
• Never commit cookie files, never store in repo, never bundle in skill package.
• Export guidance (browser extension → Netscape cookies.txt) lives in references/ethics-and-tos.md.
• Validate readability:

test -r "$HOME/.config/yt-dlp/cookies.txt" && echo readable

Pass --cookies PATH only on probe/download when user supplied the path.

Doctor

uv run python scripts/doctor.py --format json

Parses JSON ok, summary, and per-check status. Stop workflow on fail. Treat warn (e.g. missing ffmpeg) as advisory.

Help

Show dispatch table, transcript-first protocol, default paths, and ethics reference link.

Gallery (Empty Arguments)

Present common invocations when $ARGUMENTS is empty:

#	Task	Example
1	Preflight	/yt-dlp doctor
2	Probe metadata	/yt-dlp probe https://www.youtube.com/watch?v=…
3	Get subtitles	/yt-dlp transcript https://www.youtube.com/watch?v=…
4	Download (after approval)	/yt-dlp download https://www.youtube.com/watch?v=…
5	Playlist enumerate	/yt-dlp playlist https://www.youtube.com/playlist?list=…
6	User-owned cookies	/yt-dlp cookies ~/.config/yt-dlp/cookies.txt

Pick a number, a mode from the dispatch table, or paste a URL and say whether you need metadata, subtitles, or a download.

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Critical Rules

1. Probe before transcript or download — always use probe_url.py or equivalent --dump-json --no-download.
2. Transcript before download — prefer --skip-download subtitle extraction when captions exist.
3. Explicit approval for downloads — confirm rights, scope, output dir, and format.
4. User-owned cookies only — never commit, copy into repo, or invent cookie paths.
5. No ToS bypass coaching — see references/ethics-and-tos.md; refuse DRM circumvention or paywall evasion requests.
6. Not Fetch MCP — static HTML, docs pages, and non-yt-dlp hosts → Fetch MCP or curl, not this skill.
7. Not ffmpeg skill — remux, transcode, clip, waveform → /ffmpeg after download if needed.
8. Least privilege output — write only under user-approved directories, never into the agents repo tree.
9. Report provenance — title, URL, extractor, format id, and output paths in the final summary.

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Troubleshooting

See references/troubleshooting.md for extractor errors, geo blocks, signature failures, and ffmpeg merge issues.

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References

File	Use when
ethics-and-tos.md	Rights, cookies, refusal boundaries
formats-and-quality.md	Choosing -f format strings
troubleshooting.md	Errors after doctor passes

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Scripts

Script	Purpose
scripts/doctor.py	JSON preflight: yt-dlp, version, ffmpeg
scripts/probe_url.py	Read-only --dump-json wrapper
scripts/check.py	Validate skill manifest and evals

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Examples

# Preflight
uv run python scripts/doctor.py --format json

# Probe
uv run python scripts/probe_url.py --url 'https://www.youtube.com/watch?v=dQw4w9WgXcQ' --format json

# Transcript (after probe shows subs)
yt-dlp --skip-download --write-subs --write-auto-subs --sub-langs en -o '%(id)s' \
  --paths home:"$HOME/Downloads/yt-dlp/transcripts" 'URL'

# Download (after user approval)
yt-dlp -f 'bv*+ba/b' --paths home:"$HOME/Downloads/yt-dlp/media" -o '%(title).200B.%(ext)s' 'URL'