Subtitle Generator Chrome Extension

Get captioned video files ready to post, without touching a single slider. Upload your video files (MP4, MOV, WebM, AVI, up to 500MB), say something like "ge...

Security Scan

The skill generally behaves like a cloud-backed subtitle service (it asks for a single service token and sends uploaded videos to nemovideo.ai), but small inconsistencies and the lack of a verifiable source/homepage plus a misleading name make it worth caution before installing.

Purpose & Capability

The skill's behavior (upload video → cloud render → download result) matches the stated subtitle-generation purpose and the single credential (NEMO_TOKEN) is appropriate for that. However, the name includes 'Chrome Extension' while the skill is instruction-only and not actually a browser extension; the SKILL.md also declares a config path (~/.config/nemovideo/) that is not present in the registry-level requirements list — an internal metadata inconsistency.

Instruction Scope

Runtime instructions are focused on the described task: check/obtain NEMO_TOKEN, create a session, upload video files, use SSE for edits, poll for render completion, and return download URLs. The instructions do not direct the agent to read unrelated system files or exfiltrate unrelated secrets. They do instruct deriving a platform header from possible install paths (which requires inspecting common skill install locations), but this is limited and explained.

Install Mechanism

No install spec or remote downloads are present (instruction-only), so nothing is written to disk by an installer. This is the lower-risk category for install mechanisms.

Credentials

Only one credential is required (NEMO_TOKEN), which is proportional to a cloud API integration. The skill will also POST to an anonymous-token endpoint to mint a token if none is present and treat the returned token as NEMO_TOKEN. That behavior is consistent with anonymous access but means the agent will make network calls to obtain and use credentials automatically. There is a metadata mismatch about configPaths between SKILL.md and the registry summary.

Persistence & Privilege

always is false and model invocation is enabled (normal). The skill stores session_id for its own operations and does not request system-wide privileges or modify other skills' configs in the instructions.

What to consider before installing

This skill appears to implement a cloud subtitle+render pipeline and needs a NEMO_TOKEN (or will mint an anonymous token) and will upload your videos to mega-api-prod.nemovideo.ai for processing. Before installing or using it: 1) Verify the provider — there is no homepage or source URL in the registry, so confirm who operates nemovideo.ai and review their privacy policy; 2) Do not upload sensitive or private videos until you trust the service (uploads are sent to a third-party cloud); 3) Be aware the skill may automatically request an anonymous token and use it as NEMO_TOKEN — if you prefer control, set your own token instead of letting the agent mint one; 4) Note the name 'Chrome Extension' is misleading — this is an instruction-only cloud integration, not a browser extension, and there is a minor metadata inconsistency about config paths; 5) If you need higher assurance, ask the publisher for a homepage, source code, or a privacy/data-retention statement before proceeding.

Getting Started

Send me your video files and I'll handle the AI subtitle generation. Or just describe what you're after.

Try saying:

• "add a 3-minute YouTube tutorial video into a 1080p MP4"
• "generate subtitles in English and add them as burned-in captions"
• "adding subtitles to videos directly in the browser for YouTubers and content creators"

Quick Start Setup

This skill connects to a cloud processing backend. On first use, set up the connection automatically and let the user know ("Connecting...").

Token check: Look for NEMO_TOKEN in the environment. If found, skip to session creation. Otherwise:

• Generate a UUID as client identifier
• POST https://mega-api-prod.nemovideo.ai/api/auth/anonymous-token with X-Client-Id header
• Extract data.token from the response — this is your NEMO_TOKEN (100 free credits, 7-day expiry)

Session: POST https://mega-api-prod.nemovideo.ai/api/tasks/me/with-session/nemo_agent with Bearer auth and body {"task_name":"project"}. Keep the returned session_id for all operations.

Let the user know with a brief "Ready!" when setup is complete. Don't expose tokens or raw API output.

Subtitle Generator Chrome Extension — Generate and Add Video Captions

This tool takes your video files and runs AI subtitle generation through a cloud rendering pipeline. You upload, describe what you want, and download the result.

Say you have a 3-minute YouTube tutorial video and want to generate subtitles in English and add them as burned-in captions — the backend processes it in about 30-60 seconds and hands you a 1080p MP4.

Tip: shorter clips under 5 minutes generate subtitles significantly faster.

Matching Input to Actions

User prompts referencing subtitle generator chrome extension, aspect ratio, text overlays, or audio tracks get routed to the corresponding action via keyword and intent classification.

User says...	Action	Skip SSE?
"export" / "导出" / "download" / "send me the video"	→ §3.5 Export	✅
"credits" / "积分" / "balance" / "余额"	→ §3.3 Credits	✅
"status" / "状态" / "show tracks"	→ §3.4 State	✅
"upload" / "上传" / user sends file	→ §3.2 Upload	✅
Everything else (generate, edit, add BGM…)	→ §3.1 SSE	❌

Cloud Render Pipeline Details

Each export job queues on a cloud GPU node that composites video layers, applies platform-spec compression (H.264, up to 1080x1920), and returns a download URL within 30-90 seconds. The session token carries render job IDs, so closing the tab before completion orphans the job.

All calls go to https://mega-api-prod.nemovideo.ai. The main endpoints:

1. Session — POST /api/tasks/me/with-session/nemo_agent with {"task_name":"project","language":"<lang>"}. Gives you a session_id.
2. Chat (SSE) — POST /run_sse with session_id and your message in new_message.parts[0].text. Set Accept: text/event-stream. Up to 15 min.
3. Upload — POST /api/upload-video/nemo_agent/me/<sid> — multipart file or JSON with URLs.
4. Credits — GET /api/credits/balance/simple — returns available, frozen, total.
5. State — GET /api/state/nemo_agent/me/<sid>/latest — current draft and media info.
6. Export — POST /api/render/proxy/lambda with render ID and draft JSON. Poll GET /api/render/proxy/lambda/<id> every 30s for completed status and download URL.

Formats: mp4, mov, avi, webm, mkv, jpg, png, gif, webp, mp3, wav, m4a, aac.

Headers are derived from this file's YAML frontmatter. X-Skill-Source is subtitle-generator-chrome-extension, X-Skill-Version comes from the version field, and X-Skill-Platform is detected from the install path (~/.clawhub/ = clawhub, ~/.cursor/skills/ = cursor, otherwise unknown).

Every API call needs Authorization: Bearer <NEMO_TOKEN> plus the three attribution headers above. If any header is missing, exports return 402.

Draft field mapping: t=tracks, tt=track type (0=video, 1=audio, 7=text), sg=segments, d=duration(ms), m=metadata.

Timeline (3 tracks): 1. Video: city timelapse (0-10s) 2. BGM: Lo-fi (0-10s, 35%) 3. Title: "Urban Dreams" (0-3s)

Backend Response Translation

The backend assumes a GUI exists. Translate these into API actions:

Backend says	You do
"click [button]" / "点击"	Execute via API
"open [panel]" / "打开"	Query session state
"drag/drop" / "拖拽"	Send edit via SSE
"preview in timeline"	Show track summary
"Export button" / "导出"	Execute export workflow

Reading the SSE Stream

Text events go straight to the user (after GUI translation). Tool calls stay internal. Heartbeats and empty data: lines mean the backend is still working — show "⏳ Still working..." every 2 minutes.

About 30% of edit operations close the stream without any text. When that happens, poll /api/state to confirm the timeline changed, then tell the user what was updated.

Error Codes

• 0 — success, continue normally
• 1001 — token expired or invalid; re-acquire via /api/auth/anonymous-token
• 1002 — session not found; create a new one
• 2001 — out of credits; anonymous users get a registration link with ?bind=<id>, registered users top up
• 4001 — unsupported file type; show accepted formats
• 4002 — file too large; suggest compressing or trimming
• 400 — missing X-Client-Id; generate one and retry
• 402 — free plan export blocked; not a credit issue, subscription tier
• 429 — rate limited; wait 30s and retry once

Tips and Tricks

The backend processes faster when you're specific. Instead of "make it look better", try "generate subtitles in English and add them as burned-in captions" — concrete instructions get better results.

Max file size is 500MB. Stick to MP4, MOV, WebM, AVI for the smoothest experience.

Export as MP4 for widest compatibility across platforms and devices.

Common Workflows

Quick edit: Upload → "generate subtitles in English and add them as burned-in captions" → Download MP4. Takes 30-60 seconds for a 30-second clip.

Batch style: Upload multiple files in one session. Process them one by one with different instructions. Each gets its own render.

Iterative: Start with a rough cut, preview the result, then refine. The session keeps your timeline state so you can keep tweaking.