How this video got me 10 customers (made with Remotion and a Claude Opus agent)

I'm a solo dev. I needed a launch video for my Mac app and I can't do motion design, so I asked a Claude Opus agent (Claude Code) to make one. The video above is the result, and it brought me my first 10 customers. Everything in it is code. No After Effects, no stock footage, no licensed music. How it was made: Remotion : (React) for the whole film: 45 seconds, 60 fps, rendered in 1080p and 4K, in French and English. The MacBook is not a 3D model. It is CSS 3D: a base, a keyboard, a lid that rotates on its hinge, with the thickness faked by stacking slices. The cards are real renders of my app, so nothing on screen is a mockup. Even the soundtrack is synthesised in code, note by note, and synced to the frames. What surprised me most is how the agent checked its own work. It can't watch a video, so it rendered contact sheets of frames, looked at them, and fixed what was off: a title overlapping a card, a transition that left the screen empty, a table split across two cuts. It did the same at every scene change until the transitions were clean. The one thing it could not judge is the sound. It told me so itself: it measured loudness and peaks, but it can't listen. That part was on me. My takeaway: motion design with Claude is really good, as long as you give it a way to see what it makes. Ask for stills and contact sheets, not just "render the video". The app is Tack+, a panel that opens out of the MacBook notch: tackplus.app Happy to answer questions about the setup or share how the project is structured.