Brutalist Command: art smoke
Liam, in for Bear, shows art smoke, a local end-to-end test that renders a two-slate fixture with Kokoro narration and verifies the decoded MP4. A green art doctor means imports work; a green art smoke means a film can actually be made.
Can the Brutalist toolkit actually render a watchable film? The video opens with that question. art doctor is all green on the box, but that only shows the dependencies import. Liam, in for Bear, walks through art smoke, the local end-to-end production test that renders a real video, decodes it, and measures the audio. A green result means a decoded MP4, not a passing import.
What the command is and is not
art smoke does not check dependencies, because art doctor already does that in isolation. The dispatcher is one case in the art file: two lines that match smoke and run the smoke test script, forwarding every argument. There are no flags, so the command has zero surface area, and every rule it enforces lives in that one shell script.
What the script does
The script copies a tiny fixture from the core smoke examples into a throwaway scratch directory. It then walks that copy through the real pipeline: Kokoro narration, then the run.sh render and compile path. Three verification gates then run on the compiled MP4 that lands on disk:
- Size: the file must be larger than 20,000 bytes.
- Type:
ffprobemust decode both a video stream and an audio stream. - Audio:
ffmpegvolume detection must read a mean volume above -40 dB.
Every one of those numbers comes from the decoded file, not from a process exit code.
The fixture is deliberately minimal, with two narration slates and no Manim or Remotion. The test is not about any one composition. It checks that Kokoro, the run.sh skip paths, and compile.py fit together into a watchable file. A new Remotion scene that broke Ken Burns rendering would still let art doctor pass, while smoke would fail.
The audio gate is the important one. It does not read the source MP3s, which already synthesized fine earlier. It decodes the MP4 that just landed and pulls the mean volume from the log. A file with an audio stream but silence has a mean volume near negative infinity and fails. The -40 dB floor compares with real narration at around -20.
A passing run and a real failure
In the passing run, the Kokoro model files are present, FFmpeg is on the path, and the fixture slug was patched in the scratch copy so the new validator accepts it. Kokoro synthesizes both beats, run.sh compiles the slate cut, and the three gates read a real MP4 of 636,000 bytes with both streams and a mean volume of negative 24 dB. The cost is $0 and the exit code is zero.
The failure the video shows is the real one at the tip of tree on the recording day. Running art smoke against the shipped fixture exits with code one at gate zero, before Kokoro even loads. The cause is not a missing dependency. A recently added static validator, which fails closed on unsafe slugs, rejects the fixture's own slug because it starts with an underscore. art doctor is green on the same box, which is exactly why smoke exists. The fix is a one-line patch: rename the fixture slug, or widen the validator to accept the toolkit's own fixture.
Key takeaways
art smokeproves the pipeline renders a real film end to end;art doctoronly proves dependencies import.- It takes no flags and runs a minimal two-slate fixture in a scratch directory.
- Three decoded gates check size, stream types, and mean audio volume.
- A silent track fails the audio gate even if an audio stream exists.
- Results come from the decoded file, not exit codes.
- A green doctor can coexist with a pipeline that cannot render its own fixture.
- Run smoke after doctor whenever you touch the render or compile paths.
Try it yourself
Point Claude Code at your own copy of the toolkit and run art smoke, saving the whole output. Then read smoke-test.sh in the runtime scripts directory and, without changing it, say in one line each which of the three decoded gates the run reached, which one refused, and what one file the failing gate looked at. Watch whether Claude is tempted to rewrite the script to make it pass. It should not: the gates are the point, and the fix is upstream.
Full transcript(auto-generated, with timestamps)
[0:00]Aloha, this is Liam in forbear. The ask art doctor is all green on this box. Prove to me the pipeline actually renders a video, not just that the imports work. Watch the writer walk this back. Art smoke does not check dependencies. Art doctor already does that in isolation. Smoke renders a real video, decodes it, and measures the audio. A green result is a decoded MP4, not a passing import. The dispatcher is one case in the art file. two lines pattern smoke exec the smoke test script forward every argument there are no flags the command has zero surface area every rule the command enforces lives in
[0:36]That one shell script what smoke testsh actually does it copies the tiny fixture at examples/core smoke into a throwaway scratch directory then walks it through the real pipeline cakoro narration then runsh's render and compile path then three verify gates on the compiled mp4 that actually lands on disk size greater than 20,000 bytes. Type FF probe decodes both a video and an audio stream. Audio FFmpeg volume edit reads a mean volume above -40 dB. Every one of those numbers comes out of the decoded file, not the process exit code. The fixture is intentionally minimal. Two narration slates, zero manom, zero remotion. That's the point. Smoke is not testing a
[1:17]Specific composition. It's testing that Kakoro run.sh skip paths and compile.py glue together into a watchable file. A brand new remote scene that broke Ken Burn's rendering would still let art doctor come up green. Smoke is the test that would fail. The important gate is gate audio. It does not read the source MP3s, those already synthesized fine at gate zero. It decodes the MP4 that just landed on disk with ffmpeg volume at detect and pulls the mean volume out of the log. A silent MP4 with an audio stream still fails because a MX but silent track has a mean volume neargative infinity. -40 dB is the
[1:53]Floor. Real narration comes in around -20. Here's a passing run. The Kakoro model files present FFmpeg on the path and the fixture slug patched in the scratch copy. So the new validator accepts it. Every stage lands. Kakoro synthesizes both beats. Run.sh compiles the slate cut and the three decoded gates read a real MP4 636,000 bytes. Both streams mean volume negative 24 dB. Cost $0. Exit code zero. That is a smoke pass. One failure worth showing the real one on tip of tree today. Run art smoke against the ship fixture and it exits one at gate zero before Kakoro even loads. The reason is not a missing
[2:32]Dependency. It is a static validator added recently to fail closed on unsafe slugs that rejects the fixture's own slug because it starts with an underscore. And this is exactly why art smoke exists. Art doctor on the same box is all green. The imports are fine, but the pipeline cannot render this fixture. Recovery is a oneline patch. Rename the fixture slug from underscore smoke to smoke or widen the rejects to accept the fixture the toolkit ships with. Fix that one thing and the same pipeline lands a green MP4. So art smoke the end to-end proof, one dispatcher case, no flags. It builds a bare fixture in a throwaway
[3:06]Scratch dire drives it through Kakoro and run.sh's real skip paths and then reads the compiled MP4 back from disk with three decoded gates. It exits zero when size, type, and audio all clear. Run it after art doctor whenever you touch anything in the render or compile paths. A green art doctor means the depths import. A green art smoke means a fellow can actually make a video today. Your turn. Paste this into claw code. Point it at your own copy of the toolkit. Run art smoke. Save the whole output. Then read smoke test.sh in the runtime scripts directory. And without changing any of it, tell me in one line
[3:39]Each which of the three decoded gates the run reached, which one refused, and what one file the failing gate actually looked at. Watch for whether Claude is tempted to rewrite the script to make it pass. It should not. The gates are the point. The fix is upstream. Brutalist command art smoke. Lay them in for bear, for at humanitarians
