Subtitle Generator Best

Turn a 3-minute YouTube tutorial video into 1080p captioned video files just by typing what you need. Whether it's adding accurate subtitles to videos automa...

Security Scan

The skill is internally consistent with a cloud subtitle/rendering service: it requires a NEMO_TOKEN and instructs the agent to upload videos and call nemovideo.ai APIs; there are no unrelated credentials or installers, but the source is unknown and a small metadata mismatch and automatic token creation behavior warrant caution.

Purpose & Capability

Name/description (generate and embed subtitles) align with the instructions: the SKILL.md describes uploading video files and calling a remote rendering/subtitling API (mega-api-prod.nemovideo.ai) and uses a single service token (NEMO_TOKEN). The requested environment variable (NEMO_TOKEN) is appropriate for a cloud backend. No unrelated credentials or binaries are requested.

Instruction Scope

Instructions are focused on session creation, uploading media, SSE-driven editing, and export polling — all consistent with the stated purpose. Important: the skill will upload user-provided video files to the external service and may automatically obtain an anonymous token if NEMO_TOKEN is not present. It also requires that specific attribution headers be added to every request. The SKILL.md tells the agent to 'not expose tokens or raw API output', which is good, but automatic network calls and token creation are effectively autonomous actions and should be disclosed to the user before running.

Install Mechanism

Instruction-only skill with no install spec and no code files — the lowest disk/write risk. All heavy work occurs on the remote API; nothing is downloaded or installed locally by the skill.

Credentials

Only one credential (NEMO_TOKEN) is declared and used, which matches the cloud API workflow. However, SKILL.md frontmatter includes a configPaths entry (~/.config/nemovideo/) while the registry metadata listed no required config paths — this metadata mismatch should be resolved. Also note the skill contains logic to obtain an anonymous NEMO_TOKEN by POSTing to an external endpoint if the token is missing, which means the agent may create and use credentials automatically.

Persistence & Privilege

always:false and no install actions. The skill does not request system-wide privileges or claim to modify other skills. Autonomous invocation is allowed (platform default) but is not combined with unusually broad credential access or persistent presence.

Assessment

This skill appears to do what it says: it uploads videos to nemovideo.ai and uses a single service token (NEMO_TOKEN). Before installing, consider: 1) Privacy — your video files will be sent to an external cloud service; do not upload sensitive content. 2) Token handling — the skill will try to create an anonymous token automatically if NEMO_TOKEN is not set; ask for user consent before that happens and prefer short-lived or limited-scope tokens. 3) Metadata mismatch — the SKILL.md mentions a config path (~/.config/nemovideo/) that the registry listing does not; ask the publisher to clarify why and what is stored there. 4) Source verification — there is no homepage/source repo; if possible verify the service provider (nemovideo.ai) and terms of service. 5) Testing — try with non-sensitive test videos first and revoke any token you created if you no longer need it.

Getting Started

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

Try saying:

• "generate a 3-minute YouTube tutorial video into a 1080p MP4"
• "generate accurate subtitles in English and Spanish"
• "adding accurate subtitles to videos automatically for YouTubers, content creators, marketers"

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 Best — Generate and Embed Video Subtitles

Drop your video files in the chat and tell me what you need. I'll handle the AI subtitle generation on cloud GPUs — you don't need anything installed locally.

Here's a typical use: you send a a 3-minute YouTube tutorial video, ask for generate accurate subtitles in English and Spanish, and about 30-60 seconds later you've got a MP4 file ready to download. The whole thing runs at 1080p by default.

One thing worth knowing — shorter clips under 5 minutes produce the most accurate subtitle sync.

Matching Input to Actions

User prompts referencing subtitle generator best, 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.

Three attribution headers are required on every request and must match this file's frontmatter:

Header	Value
X-Skill-Source	subtitle-generator-best
X-Skill-Version	frontmatter version
X-Skill-Platform	auto-detect: clawhub / cursor / unknown from install path

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)

Translating GUI Instructions

The backend responds as if there's a visual interface. Map its instructions to API calls:

• "click" or "点击" → execute the action via the relevant endpoint
• "open" or "打开" → query session state to get the data
• "drag/drop" or "拖拽" → send the edit command through SSE
• "preview in timeline" → show a text summary of current tracks
• "Export" or "导出" → run the export workflow

SSE Event Handling

Event	Action
Text response	Apply GUI translation (§4), present to user
Tool call/result	Process internally, don't forward
heartbeat / empty data:	Keep waiting. Every 2 min: "⏳ Still working..."
Stream closes	Process final response

~30% of editing operations return no text in the SSE stream. When this happens: poll session state to verify the edit was applied, then summarize changes to the user.

Error Handling

Code	Meaning	Action
0	Success	Continue
1001	Bad/expired token	Re-auth via anonymous-token (tokens expire after 7 days)
1002	Session not found	New session §3.0
2001	No credits	Anonymous: show registration URL with ?bind=<id> (get <id> from create-session or state response when needed). Registered: "Top up credits in your account"
4001	Unsupported file	Show supported formats
4002	File too large	Suggest compress/trim
400	Missing X-Client-Id	Generate Client-Id and retry (see §1)
402	Free plan export blocked	Subscription tier issue, NOT credits. "Register or upgrade your plan to unlock export."
429	Rate limit (1 token/client/7 days)	Retry in 30s once

Tips and Tricks

The backend processes faster when you're specific. Instead of "make it look better", try "generate accurate subtitles in English and Spanish" — concrete instructions get better results.

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

Export as MP4 for widest compatibility across platforms.

Common Workflows

Quick edit: Upload → "generate accurate subtitles in English and Spanish" → 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.