Add Subtitle To Video Capcut

Skip the learning curve of professional editing software. Describe what you want — add subtitles to my video like CapCut does automatically — and get caption...

Security Scan

The skill mostly does what it says (cloud subtitle rendering), but there are mismatches between the declared requirements/metadata and the runtime instructions, plus it will upload user videos to an external service (nemovideo.ai) — verify you trust that service and the token/storage behavior before installing.

Purpose & Capability

The declared purpose (auto-generate/burn-in subtitles) matches the runtime API calls to a cloud render backend. However the registry metadata lists NEMO_TOKEN as a required environment variable while the runtime instructions explicitly describe obtaining an anonymous token from the service if no token is provided — this is an inconsistency. The SKILL.md frontmatter also lists a config path (~/.config/nemovideo/) while the registry summary stated no config paths; that mismatch should be resolved.

Instruction Scope

Instructions are concrete and limited to the stated task: creating anonymous tokens, establishing a session, uploading video files, using SSE for edits, querying credits/state, and exporting rendered video. These steps require network calls and file uploads (multipart form uploads or URLs). The instructions also tell the agent not to display raw tokens or responses. There is no scope creep to unrelated system resources, but the skill will send user video and related metadata to an external API — expected for cloud rendering but a privacy consideration.

Install Mechanism

Instruction-only skill with no install spec or code files; nothing is written to disk by the skill itself in its install step. Low install risk.

Credentials

Only NEMO_TOKEN is referenced as a credential (reasonable for a third-party API), but registry metadata declares it required while SKILL.md documents an anonymous-token flow if NEMO_TOKEN is absent. Additionally the SKILL.md frontmatter indicates a config path (~/.config/nemovideo/) which the registry summary omitted. These inconsistencies raise questions about whether the skill will expect pre-provisioned credentials or will create and persist tokens/session state on disk.

Persistence & Privilege

always is false and the skill does not request elevated platform-wide privileges. The frontmatter references a config directory (~/.config/nemovideo/), and the instructions imply storing session_id/token for subsequent requests; it is not explicit whether or where those values are persisted (in-memory vs disk). Confirm where session/token are stored and whether the skill will write to that config directory.

What to consider before installing

This skill sends your video files (and probably some metadata) to a third-party service at mega-api-prod.nemovideo.ai to do cloud subtitle/rendering. That behaviour is consistent with the advertised feature but has privacy and trust implications: only upload videos you are comfortable sharing, and verify the service's terms/privacy. Be aware of two mismatches: the registry marks NEMO_TOKEN as required, but the skill can obtain an anonymous token itself (100 free credits, 7 days), and the frontmatter mentions a config path (~/.config/nemovideo/) even though the registry summary said none. Before installing, ask the publisher or inspect runtime logs to confirm (1) whether tokens/session IDs are persisted to disk and where, (2) whether you must provide a pre-existing NEMO_TOKEN or the skill will create/rotate one automatically, and (3) the retention and privacy policy of nemovideo.ai. If you need confidentiality, do not upload sensitive videos to this service.

Getting Started

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

Try saying:

• "add my video clips"
• "export 1080p MP4"
• "add subtitles to my video like"

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.

Add Subtitle to Video CapCut — Auto-Generate and Burn In Captions

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

Say you have a 2-minute tutorial video in MP4 format and want to add subtitles to my video like CapCut does automatically — the backend processes it in about 30-60 seconds and hands you a 1080p MP4.

Tip: shorter clips under 60 seconds generate subtitles fastest.

Matching Input to Actions

User prompts referencing add subtitle to video 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.

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

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

Header	Value
X-Skill-Source	add-subtitle-to-video-capcut
X-Skill-Version	frontmatter version
X-Skill-Platform	auto-detect: clawhub / cursor / unknown from install path

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 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

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.

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)

Tips and Tricks

The backend processes faster when you're specific. Instead of "make it look better", try "add subtitles to my video like CapCut does automatically" — 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.

Common Workflows

Quick edit: Upload → "add subtitles to my video like CapCut does automatically" → 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.