yt-loader

Claude Code plugin. /yt <youtube or tiktok url> pulls the video's captions into context, gives you a summary, and leaves the full transcript loaded so you can ask questions.

No API key, no packages to install. It's Node with zero dependencies that pulls the site's own caption tracks (the same thing the CC button loads), and Node is already on any machine running Claude Code.

Install

claude plugin marketplace add ericalexander/yt-loader
claude plugin install yt-loader@ericalexander

Or inside a session: /plugin marketplace add ericalexander/yt-loader, then /plugin install yt-loader@ericalexander.

To hack on a local checkout without installing: claude --plugin-dir ./plugins/yt-loader

Use

/yt https://www.youtube.com/watch?v=VIDEO_ID
/yt https://youtu.be/VIDEO_ID --timestamps
/yt https://www.tiktok.com/@user/video/1234567890123456789
/yt https://vm.tiktok.com/SHORTCODE/

Pasting a YouTube or TikTok link and asking a question also triggers it. Follow-up questions answer from the transcript already in context; nothing is re-fetched.

Transcripts cache in ~/.cache/yt-transcript/.

MCP server (for sandboxed sessions)

The plugin also ships an MCP server exposing two tools, youtube_transcript and tiktok_transcript (each accepts either kind of link; they route by URL). It exists because the fetch script runs wherever Claude's shell is, and in Claude's cloud sandbox (and the desktop app's sandboxed VM) youtube.com and tiktok.com are blocked by an egress proxy. An MCP server launched by the Claude desktop app runs on your own machine with normal network access, so the same fetch works and the transcript comes back as a tool result.

The skill prefers the tools when present and falls back to the script otherwise. Nothing to configure: .mcp.json in the plugin registers the server, and it is the same zero-dependency Node code as the script.

To run it by hand, e.g. from a claude_desktop_config.json:

{ "mcpServers": { "yt-loader": { "command": "node", "args": ["/path/to/plugins/yt-loader/mcp/server.mjs"] } } }

Layout

This repo is a one-plugin marketplace, so more plugins can be added under plugins/ and listed in .claude-plugin/marketplace.json.

.claude-plugin/marketplace.json
plugins/yt-loader/
  .claude-plugin/plugin.json
  .mcp.json                          # registers mcp/server.mjs
  lib/transcript.mjs                 # YouTube fetch + format logic + URL router, shared
  lib/tiktok.mjs                     # TikTok fetch (page data + WebVTT)
  mcp/server.mjs                     # stdio MCP server: youtube_transcript, tiktok_transcript
  skills/yt/SKILL.md
  skills/yt/scripts/fetch_transcript.mjs   # thin CLI over lib/

How the fetch works

YouTube:

1. GET the watch page to pick up the InnerTube API key.
2. POST youtubei/v1/player as the Android client; the response carries the title and the list of caption tracks.
3. GET the chosen track's timed-text XML and flatten it.

If step 2 returns no captions it falls back to the player response embedded in the watch page. Manual captions are preferred over auto-generated in each requested language.

TikTok:

1. GET the video page (short links redirect to the full /@user/video/ID URL).
2. Read the JSON TikTok embeds for its own front end (__UNIVERSAL_DATA_FOR_REHYDRATION__); the post's caption tracks are listed under video.claInfo.captionInfos (fallback: video.subtitleInfos) with signed, expiring WebVTT URLs.
3. GET the chosen track's WebVTT and flatten it.

TikTok only exposes auto-generated (ASR) captions here, so every TikTok transcript is marked auto-generated.

Known limits

• Videos with captions disabled return nothing; the skill says so instead of guessing.
• If youtube.com is blocked on the network (proxied sandboxes), the script says so and points at the MCP server instead of retrying.
• YouTube and TikTok rate-limit or bot-check cloud/datacenter IPs. From a home machine it's fine.
• Auto-generated captions have no punctuation (YouTube) or guessed punctuation (TikTok) and mangle proper nouns.
• TikTok photo/slideshow posts and private or deleted posts return nothing.