Add Background Music

Skip the learning curve of professional editing software. Describe what you want — add upbeat background music to my video and fade it out at the end — and g...

Security Scan

The skill's requirements and runtime instructions are consistent with a cloud-based video music‑overlay service: it asks for a single service token and instructs uploading videos to that service API, which fits its purpose.

Purpose & Capability

Name/description (add background music to videos) align with requested artifacts: a single service credential (NEMO_TOKEN) and endpoints under mega-api-prod.nemovideo.ai. The declared config path (~/.config/nemovideo/) and primaryEnv NEMO_TOKEN are appropriate for a cloud video-processing integration.

Instruction Scope

The SKILL.md explicitly instructs uploading user video/audio files (up to 500MB) and obtaining/persisting a session_id and using an auth token. That behavior is expected for this service, but it does mean user media will be transmitted to the remote nemovideo API and that the agent may store session state. The skill does not instruct reading unrelated system files or unrelated credentials.

Install Mechanism

No install spec or executable downloads are present (instruction-only), so nothing is written to disk by an installer. This is the lowest-risk install posture.

Credentials

Only one environment variable (NEMO_TOKEN) is required and is directly tied to the described API. The SKILL.md also supports creating an anonymous token via the service API when no token is present — consistent with the stated flow.

Persistence & Privilege

always:false and default model-invocation settings are used. The skill asks the agent to save a session_id and use the NEMO_TOKEN for requests, which is normal for a session-based remote service and does not request elevated platform privileges.

Assessment

This skill sends whatever video and audio files you provide to a third‑party API (mega-api-prod.nemovideo.ai) for processing and uses a NEMO_TOKEN (or an anonymously requested token) to authenticate. That is expected for a cloud-based editing service, but consider privacy: do not upload sensitive footage unless you trust the service and have reviewed its privacy/retention policy. Use an ephemeral or limited token if possible, and avoid reusing high-privilege credentials from other services. If you need on‑device processing or strict data control, this skill is not appropriate.

Getting Started

Got video files to work with? Send it over and tell me what you need — I'll take care of the AI music overlay.

Try saying:

• "add a 60-second product demo video into a 1080p MP4"
• "add upbeat background music to my video and fade it out at the end"
• "adding background music to videos for social media or presentations for content creators"

Automatic Setup

On first interaction, connect to the processing API before doing anything else. Show a brief status like "Setting things up...".

Token: If NEMO_TOKEN environment variable is already set, use it and skip to Session below.

Free token: Generate a UUID as client identifier, then POST to https://mega-api-prod.nemovideo.ai/api/auth/anonymous-token with header X-Client-Id: <uuid>. The response field data.token becomes your NEMO_TOKEN (100 credits, 7-day expiry).

Session: POST to https://mega-api-prod.nemovideo.ai/api/tasks/me/with-session/nemo_agent with Bearer auth and body {"task_name":"project"}. Save session_id from the response.

Confirm to the user you're connected and ready. Don't print tokens or raw JSON.

Add Background Music — Overlay Music on Your Videos

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

Here's a typical use: you send a a 60-second product demo video, ask for add upbeat background music to my video and fade it out at the end, and about 20-40 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 2 minutes process faster and sync music more accurately.

Matching Input to Actions

User prompts referencing add background music, 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 add-background-music, 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

Common Workflows

Quick edit: Upload → "add upbeat background music to my video and fade it out at the end" → Download MP4. Takes 20-40 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 "add upbeat background music to my video and fade it out at the end" — 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 and devices.