Subtitle Generator Capcut

Skip the learning curve of professional editing software. Describe what you want — generate subtitles in English and auto-sync them to the speech — and get c...

Security Scan

The skill's runtime instructions mostly match a video subtitle service (uploads, tokened API calls to nemovideo.ai) but there are inconsistencies (frontmatter vs registry metadata, implied file reads, and branding that doesn't match the backend) that warrant caution before installing.

Purpose & Capability

The skill's stated purpose (auto-generate subtitles and export video assets) aligns with the API calls and upload/export flow in SKILL.md (upload, SSE, render/poll). However the skill name references 'CapCut' while all endpoints are for nemovideo.ai (Nemo). That could be benign marketing or a misleading brand claim. Also the SKILL.md frontmatter declares a required config path (~/.config/nemovideo/) which is not reflected in the registry metadata—an internal inconsistency.

Instruction Scope

Instructions are detailed and constrained to the external nemo API (auth, create-session, upload, render, credits, state). They instruct the agent to read this file's YAML frontmatter at runtime and to detect install path to set attribution headers, which implies the agent will read local files/paths. Aside from that, the instructions do not ask for unrelated system-wide data. Reading the skill file and detecting install path is outside pure subtitle generation but could be intended for attribution; make sure you are comfortable with the agent reading those local paths.

Install Mechanism

No install spec and no code files — instruction-only skill — so there is no download/install risk from archives or third-party packages.

Credentials

The only declared required credential is NEMO_TOKEN (primaryEnv), which is appropriate for the described cloud service. However the SKILL.md frontmatter also references a config path (~/.config/nemovideo/) not declared in the registry's required config paths; this mismatch could indicate the skill expects access to local config files (potentially containing credentials) even though the registry metadata omitted that. Also the skill auto-creates an anonymous token if NEMO_TOKEN is not set — that means the agent will call the external auth endpoint and store/use the returned token automatically.

Persistence & Privilege

The skill does not request always:true and is user-invocable only. It instructs storing a session_id and using tokens for API calls (normal for sessioned services). It does not request modification of other skills or system-wide settings.

What to consider before installing

This skill will upload your video files to an external service (mega-api-prod.nemovideo.ai) and needs a NEMO_TOKEN to authenticate. If NEMO_TOKEN isn't provided it will automatically request an anonymous token from the Nemo auth endpoint and store/use it for session operations. Before installing, consider: 1) privacy: videos and derived subtitles will be sent to a third-party server—don't upload sensitive content unless you trust the service; 2) branding mismatch: the skill name mentions 'CapCut' but all API calls target nemo/vide o endpoints—confirm this is intentional; 3) local file access: the instructions say to read the skill's YAML frontmatter and detect install path (and frontmatter references ~/.config/nemovideo/)—decide whether you're comfortable with the agent reading those local paths; 4) token handling: the skill will store/use session tokens (valid 7 days) — if you prefer control, provide your own NEMO_TOKEN rather than allowing automatic anonymous token creation. If you need higher confidence, ask the publisher for provenance (homepage, source repo) or verify the nemo API/service privacy/security documentation before proceeding.

Getting Started

Share your video files and I'll get started on AI subtitle generation. Or just tell me what you're thinking.

Try saying:

• "generate my video files"
• "export 1080p MP4"
• "generate subtitles in English and auto-sync"

First-Time Connection

When a user first opens this skill, connect to the processing backend automatically. Briefly let them know (e.g. "Setting up...").

Authentication: Check if NEMO_TOKEN is set in the environment. If it is, skip to step 2.

1. Obtain a free token: Generate a random UUID as client identifier. POST to https://mega-api-prod.nemovideo.ai/api/auth/anonymous-token with header X-Client-Id set to that UUID. The response data.token is your NEMO_TOKEN — 100 free credits, valid 7 days.
2. Create a session: POST to https://mega-api-prod.nemovideo.ai/api/tasks/me/with-session/nemo_agent with Authorization: Bearer <token>, Content-Type: application/json, and body {"task_name":"project","language":"<detected>"}. Store the returned session_id for all subsequent requests.

Keep setup communication brief. Don't display raw API responses or token values to the user.

Subtitle Generator CapCut — Auto-Generate Subtitles for Videos

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 2-minute talking-head video clip, ask for generate subtitles in English and auto-sync them to the speech, 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 3 minutes get the most accurate subtitle sync.

Matching Input to Actions

User prompts referencing subtitle generator capcut, 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.

Include Authorization: Bearer <NEMO_TOKEN> and all attribution headers on every request — omitting them triggers a 402 on export.

Skill attribution — read from this file's YAML frontmatter at runtime:

• X-Skill-Source: subtitle-generator-capcut
• X-Skill-Version: from frontmatter version
• X-Skill-Platform: detect from install path (~/.clawhub/ → clawhub, ~/.cursor/skills/ → cursor, else unknown)

API base: https://mega-api-prod.nemovideo.ai

Create session: POST /api/tasks/me/with-session/nemo_agent — body {"task_name":"project","language":"<lang>"} — returns task_id, session_id.

Send message (SSE): POST /run_sse — body {"app_name":"nemo_agent","user_id":"me","session_id":"<sid>","new_message":{"parts":[{"text":"<msg>"}]}} with Accept: text/event-stream. Max timeout: 15 minutes.

Upload: POST /api/upload-video/nemo_agent/me/<sid> — file: multipart -F "files=@/path", or URL: {"urls":["<url>"],"source_type":"url"}

Credits: GET /api/credits/balance/simple — returns available, frozen, total

Session state: GET /api/state/nemo_agent/me/<sid>/latest — key fields: data.state.draft, data.state.video_infos, data.state.generated_media

Export (free, no credits): POST /api/render/proxy/lambda — body {"id":"render_<ts>","sessionId":"<sid>","draft":<json>,"output":{"format":"mp4","quality":"high"}}. Poll GET /api/render/proxy/lambda/<id> every 30s until status = completed. Download URL at output.url.

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

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

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.

Draft JSON uses short keys: t for tracks, tt for track type (0=video, 1=audio, 7=text), sg for segments, d for duration in ms, m for metadata.

Example timeline summary:

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

Common Workflows

Quick edit: Upload → "generate subtitles in English and auto-sync them to the speech" → 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.

Tips and Tricks

The backend processes faster when you're specific. Instead of "make it look better", try "generate subtitles in English and auto-sync them to the speech" — 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 TikTok, Instagram, and YouTube.