/index-youtube

Index YouTube video transcripts into a searchable knowledge base. Supports two modes depending on available tools.

# /index-youtube

Index YouTube video transcripts into a searchable knowledge base. Supports two modes depending on available tools.

## Prerequisites

Check that yt-dlp is available:

```bash
which yt-dlp || echo "MISSING: install yt-dlp (brew install yt-dlp / pip install yt-dlp / pipx install yt-dlp)"
```

## Arguments

Parse `$ARGUMENTS` for channel handles or "all":
- If empty or "all": index all channels (from config or ask user)
- If one or more handles: index only those channels (e.g., `GregIsenberg ycombinator`)
- Optional flags: `-n <limit>` (max videos per channel, default 10), `--dry-run` (parse only)

## Mode Detection

Check which mode is available:

### Mode 1: With solograph MCP (recommended)

If MCP tools `source_search`, `source_list`, `source_tags` are available, use solograph for indexing and search.

**Setup (if not yet installed):**
```bash
# Install solograph
pip install solograph
# or
uvx solograph
```

**Indexing via solograph CLI:**
```bash
# Single channel
solograph-cli index-youtube -c GregIsenberg -n 10

# Multiple channels
solograph-cli index-youtube -c GregIsenberg -c ycombinator -n 10

# All channels (from channels.yaml in solograph config)
solograph-cli index-youtube -n 10

# Dry run (parse only, no DB writes)
solograph-cli index-youtube --dry-run
```

If `solograph-cli` is not on PATH, try:
```bash
uvx solograph-cli index-youtube -c <handle> -n 10
```

**Verification via MCP:**
- `source_list` — check that youtube source appears
- `source_search("startup idea", source="youtube")` — test semantic search
- `source_tags` — see auto-detected topics from transcripts
- `source_related(video_id)` — find related videos by tags

### Mode 2: Without MCP (standalone fallback)

If solograph MCP tools are NOT available, use yt-dlp directly to download transcripts and analyze them.

**Step 1: Download video list**
```bash
# Get recent video URLs from a channel
yt-dlp --flat-playlist --print url "https://www.youtube.com/@GregIsenberg/videos" | head -n 10
```

**Step 2: Download transcripts**
```bash
# Download auto-generated subtitles (no video download)
yt-dlp --write-auto-sub --sub-lang en --skip-download --sub-format vtt \
  -o "docs/youtube/%(channel)s/%(title)s.%(ext)s" \
  "<video-url>"
```

**Step 3: Convert VTT to readable text**
```bash
# Strip VTT formatting (timestamps, positioning)
sed '/^$/d; /^[0-9]/d; /^NOTE/d; /^WEBVTT/d; /-->/d' docs/youtube/channel/video.vtt | \
  awk '!seen[$0]++' > docs/youtube/channel/video.txt
```

**Step 4: Create index**

Read each transcript with the Read tool. For each video, extract:
- Title (from filename or yt-dlp metadata)
- Key topics and insights
- Actionable takeaways
- Timestamps for notable segments (if chapter markers exist)

Write a summary index to `docs/youtube/index.md`:

```markdown
# YouTube Knowledge Index

## Channel: {channel_name}

### {video_title}
- **URL:** {url}
- **Key topics:** {topic1}, {topic2}
- **Insights:** {summary}
- **Actionable:** {takeaway}
```

**Step 5: Search indexed content**

With transcripts saved as text files, use Grep to search:
```bash
# Search across all transcripts
grep -ri "startup idea" docs/youtube/
```

## Output

Report to the user:
1. Number of videos indexed
2. Number of transcripts downloaded (vs skipped — no transcript available)
3. How many had chapter markers
4. Index file location
5. How to search the indexed content (MCP tool or Grep command)

## Common Issues

### "MISSING: install yt-dlp"
**Cause:** yt-dlp not installed.
**Fix:** Run `brew install yt-dlp` (macOS), `pip install yt-dlp`, or `pipx install yt-dlp`.

### Videos skipped (no transcript)
**Cause:** Video has no auto-generated or manual subtitles.
**Fix:** This is expected — some videos lack transcripts. Only videos with available subtitles can be indexed.

### Rate limiting from YouTube
**Cause:** Too many requests in short time.
**Fix:** Reduce `-n` limit, add `--sleep-interval 2` to yt-dlp commands, or use `--cookies-from-browser chrome` for authenticated access.

### solograph-cli not found
**Cause:** solograph not installed or not on PATH.
**Fix:** Install with `pip install solograph` or `uvx solograph`. Check `which solograph-cli`.