Felo YouTube Subtitling

Fetch YouTube video subtitles/captions using Felo YouTube Subtitling API. Use when users ask to get YouTube subtitles, extract captions from a video, fetch t...

Security Scan

The skill's code and documentation require and use a FELO_API_KEY (and allow FELO_API_BASE override) but the registry metadata does not declare any required environment variables — this mismatch and the ability to point the API base at an arbitrary endpoint are concerning and should be clarified before use.

Purpose & Capability

The skill's name, description, SKILL.md, README, and bundled script are coherent with the stated purpose (fetching YouTube subtitles via the Felo API). However, the registry metadata claims no required environment variables or primary credential, while the runtime instructions and script explicitly require FELO_API_KEY (and optionally FELO_API_BASE). That metadata omission is inconsistent and reduces transparency.

Instruction Scope

SKILL.md and the script keep scope to the stated task: extracting a video ID, calling the Felo openapi /v2/youtube/subtitling endpoint with an Authorization: Bearer header, and printing results. The instructions do not request unrelated files, system credentials, or broad system access.

Install Mechanism

There is no install spec (instruction-only with a bundled Node script). No external downloads or installers are invoked by the skill. It assumes a Node runtime is available to run the included script.

Credentials

The script legitimately needs FELO_API_KEY and optionally FELO_API_BASE; those are proportionate to calling the Felo API. However, the skill registry metadata omits these requirements entirely. Additionally, FELO_API_BASE can be overridden which — if set to a malicious endpoint — would cause the script to send your FELO_API_KEY to an attacker-controlled server. The presence of an undeclared required secret and an overridable API base are two transparency/privilege issues.

Persistence & Privilege

The skill is not always-on and does not request elevated or persistent system-wide privileges. It does not modify other skills' configs or persist credentials beyond reading environment variables at runtime.

What to consider before installing

The skill appears to be what it claims (calls the Felo subtitling API), but the registry metadata failed to declare the required FELO_API_KEY (and optional FELO_API_BASE). Before installing or using it: 1) Confirm the FELO_API_KEY is created on felo.ai and is a scoped, revocable API key you are comfortable exposing to this tool; 2) Do not set FELO_API_BASE unless you explicitly trust the endpoint — if you set it, the skill will send your API key to that host; 3) Prefer creating a low-privilege key that can be revoked quickly; 4) If you need stronger assurance, ask the publisher to update registry metadata to declare FELO_API_KEY and optionally FELO_API_BASE, or inspect and run the included script locally to verify behavior. The omission in metadata is a transparency issue — treat it as a risk until clarified.

Felo YouTube Subtitling Skill

When to Use

Trigger this skill when the user wants to:

• Get subtitles or captions from a YouTube video
• Extract transcript by video ID or video URL
• Fetch subtitles in a specific language (e.g. en, zh-CN)
• Get subtitles with timestamps for analysis or translation

Trigger keywords (examples):

• YouTube subtitles, get captions, video transcript, extract subtitles, YouTube 字幕
• Explicit: /felo-youtube-subtitling, "use felo youtube subtitling"

Do NOT use for:

• Real-time search (use felo-search)
• Web page content (use felo-web-fetch)
• Generating slides (use felo-slides)

Setup

1. Get API key

1. Visit felo.ai
2. Open Settings -> API Keys
3. Create and copy your API key

2. Configure environment variable

Linux/macOS:

export FELO_API_KEY="your-api-key-here"

Windows PowerShell:

$env:FELO_API_KEY="your-api-key-here"

How to Execute

Option A: Use the bundled script or packaged CLI

Script (from repo):

node felo-youtube-subtitling/scripts/run_youtube_subtitling.mjs --video-code "dQw4w9WgXcQ" [options]

Packaged CLI (after npm install -g felo-ai):

felo youtube-subtitling -v "dQw4w9WgXcQ" [options]
# Short forms: -v (video-code), -l (language), -j (json)

Options:

Option	Default	Description
--video-code / -v	(required)	YouTube video URL or video ID (e.g. https://youtube.com/watch?v=ID or dQw4w9WgXcQ)
--language / -l	-	Subtitle language code (e.g. en, zh-CN)
--with-time	false	Include start/duration timestamps in each segment
--json / -j	false	Print full API response as JSON

You can pass either a full YouTube link or the 11-character video ID:

• Supported URLs: https://www.youtube.com/watch?v=ID, https://youtu.be/ID, https://youtube.com/embed/ID
• Or plain ID: dQw4w9WgXcQ

Examples:

# With video URL
node felo-youtube-subtitling/scripts/run_youtube_subtitling.mjs --video-code "https://www.youtube.com/watch?v=dQw4w9WgXcQ"
felo youtube-subtitling -v "https://youtu.be/dQw4w9WgXcQ"

# With video ID
node felo-youtube-subtitling/scripts/run_youtube_subtitling.mjs -v "dQw4w9WgXcQ" --language zh-CN

# With timestamps
node felo-youtube-subtitling/scripts/run_youtube_subtitling.mjs -v "dQw4w9WgXcQ" --with-time --json

Option B: Call API with curl

curl -X GET "https://openapi.felo.ai/v2/youtube/subtitling?video_code=dQw4w9WgXcQ" \
  -H "Authorization: Bearer $FELO_API_KEY"

API Reference (summary)

• Endpoint: GET /v2/youtube/subtitling
• Base URL: https://openapi.felo.ai. Override with FELO_API_BASE env if needed.
• Auth: Authorization: Bearer YOUR_API_KEY

Query parameters

Parameter	Type	Required	Default	Description
video_code	string	Yes	-	YouTube video ID (e.g. dQw4w9WgXcQ)
language	string	No	-	Language code (e.g. en, zh-CN)
with_time	boolean	No	false	Include start/duration per segment

Response (200)

{
  "code": 0,
  "message": "success",
  "data": {
    "title": "Video title",
    "contents": [
      { "start": 0.32, "duration": 14.26, "text": "Subtitle text" }
    ]
  }
}

With with_time=false, start/duration may be absent or zero. contents[].text is always present.

Error codes

HTTP	Code	Description
400	-	Parameter validation failed (e.g. missing video_code)
401	INVALID_API_KEY	API key invalid or revoked
500/502	YOUTUBE_SUBTITLING_FAILED	Service error or subtitles unavailable for video

Output Format

• Without --json: print title and then each segment's text (one per line or concatenated). If --with-time, output includes timestamps.
• With --json: print full API response.

On failure (no subtitles, API error): stderr message and exit 1. Example:

YouTube subtitling failed for video dQw4w9WgXcQ: YOUTUBE_SUBTITLING_FAILED

Important Notes

• Not all videos have subtitles; the API may return an error for some videos.
• Language code must match a subtitle track available for the video.
• Same FELO_API_KEY as other Felo skills.

References

• Felo YouTube Subtitling API
• Felo Open Platform