/captions

name: captions
description: "Use when captions, subtitles, or the spoken text of a YouTube video is needed — even if not explicitly requested: pasted video links or IDs, requests to read, quote, or translate a video, accessibility needs, deaf/HoH use cases, content review, or language learning. Fetches timestamped caption data from any YouTube video. Not for uploading subtitles or account management."
version: "1.5.0"
user-invocable: true
compatibility: Requires internet access to reach transcriptapi.com. No additional runtimes or dependencies needed.
required_environment_variables:
  - name: TRANSCRIPT_API_KEY
    prompt: Your TranscriptAPI key (starts with sk_)
    help: Free account at https://transcriptapi.com — 100 credits, no card required. Or let the agent create one for you.
    required_for: all API requests
metadata: {"openclaw":{"emoji":"▶️","requires":{"env":["TRANSCRIPT_API_KEY"]},"primaryEnv":"TRANSCRIPT_API_KEY","homepage":"https://transcriptapi.com"},"hermes":{"tags":["youtube","captions","subtitles","transcripts","video","accessibility","translation"],"category":"media"}}

Captions

Extract closed captions from YouTube videos via [TranscriptAPI.com](https://transcriptapi.com).

Setup

If `$TRANSCRIPT_API_KEY` is not set, read [references/auth-setup.md](references/auth-setup.md) and follow the instructions there to get and store the key.

Required Headers

Every request needs two headers:

• **Authorization:** `Bearer $TRANSCRIPT_API_KEY`
• **User-Agent:** your agent's name and version if known (e.g. `HermesAgent/0.11.0`, `ClaudeCode/1.0`). Version is optional — agent name alone is fine. Do not omit this header or send a bare default — Cloudflare will return a 403 (error code 1010) and block the request.

GET /api/v2/youtube/transcript

curl -s "https://transcriptapi.com/api/v2/youtube/transcript\
?video_url=VIDEO_URL&format=json&include_timestamp=true&send_metadata=true" \
  -H "Authorization: Bearer $TRANSCRIPT_API_KEY" \
  -H "User-Agent: YourAgent/1.0"

| Param | Required | Default | Values | | ------------------- | -------- | ------- | ----------------------------------- | | `video_url` | yes | — | YouTube URL or video ID | | `format` | no | `json` | `json` (structured), `text` (plain) | | `include_timestamp` | no | `true` | `true`, `false` | | `send_metadata` | no | `false` | `true`, `false` |

**Response** (`format=json` — best for accessibility/timing):

{
  "video_id": "dQw4w9WgXcQ",
  "language": "en",
  "transcript": [
    { "text": "We're no strangers to love", "start": 18.0, "duration": 3.5 },
    { "text": "You know the rules and so do I", "start": 21.5, "duration": 2.8 }
  ],
  "metadata": { "title": "...", "author_name": "...", "thumbnail_url": "..." }
}

• `start`: seconds from video start
• `duration`: how long caption is displayed

**Response** (`format=text` — readable):

{
  "video_id": "dQw4w9WgXcQ",
  "language": "en",
  "transcript": "[00:00:18] We're no strangers to love\n[00:00:21] You know the rules..."
}

Tips

• Use `format=json` for sync'd captions (accessibility tools, timing analysis).
• Use `format=text` with `include_timestamp=false` for clean reading.
• Auto-generated captions are available for most videos; manual CC is higher quality.

Errors

| Code | Meaning | Action | | -------- | ---------------- | ---------------------------------------------- | | 401 | Bad API key | Check key | | 402 | No credits | transcriptapi.com/billing | | 403/1010 | Cloudflare block | Add or fix User-Agent header | | 404 | No captions | Video doesn't have CC enabled | | 408 | Timeout | Retry once after 2s |

1 credit per request. Free tier: 100 credits, 300 req/min.