Empty Folder to MP4 in 162 Seconds: What a Coding Agent Can't Do With Video

Description and use

Coding agents can generate video from code but lack visual verification, leading to silent failures. The demo shows a 162‑second pipeline from empty folder to MP4, with render time scaling linearly. Reliability can be improved by providing component libraries and rendering stills during iteration.

Problem

Coding agents can generate code that renders deterministic video frames, but they lack a way to verify visual quality, leading to silent failures such as black screens or incorrect layouts.

Outcome

The demo shows that a full pipeline from empty folder to MP4 takes about 162 seconds on a clean Windows 11 machine, with npm install accounting for two‑thirds of the time. Render time scales linearly with duration (~26 fps). However, the agent’s lack of visual verification can lead to silent failures, which can be mitigated by providing component libraries and rendering stills during development.

Workflow

• 1. Scaffold a new project with npx create-video@latest --yes --blank demo. 2. Add Remotion skills via npx skills add remotion-dev/skills -a claude-code -y. 3. Render the first video with npx remotion render MyComp out/video.mp4. 4. Measure timings: scaffold (~1 m 56 s), skill install (6 s), cold render (≈40 s), warm render (≈12 s).
• 5. Verify visual quality by inspecting the MP4 or rendering stills with npx remotion still MyComp out/f.png --frame=45. 6. If visual defects are found, provide the agent with a pre‑built component library or adjust the code manually.
• 7. Iterate until the rendered video meets visual expectations.

Evidence

Total to first MP4: about three minutes.

Source

The agent has no way to know whether what it rendered is any good.

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The npm install is two‑thirds of it.

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If your agent "can't see the skills", check which directory got them before you debug anything else.

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The verification gap. "It compiles" is not "it looks good."

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