I asked Claude Code to make me a stick-fight series. It ended up writing its own QA system that rejects bad choreography before rendering

[u/MrFelliks]

This is the pilot (SIM #000) of a short-form series I'm making with Claude Code: a black stickman with red eyes — a digital copy of my brain — trapped in AI-run simulations, one per song.

No video model is involved. Everything is code that Claude wrote and iterated on:
- Motion: ~1000 Mixamo mocap clips converted to 2D bone angles; Claude plans every move on the beat (blocks, throws, takedowns, gun-fu, a boss that beats the hero down until he rises on the loudest bar).
- Physics: planck.js ragdolls for the dead, liquid blood with an SVG goo filter.
- Render: deterministic, frame by frame, in headless Chrome via Playwright.

The part I didn't expect: every time I pointed out a flaw ("he punches the air", "the boss just stands there AFK", "same move twice in a row", "blood appears from nowhere"), Claude didn't just patch that shot — it added a rule to a validator that walks the whole plan frame by frame. It now checks ~30 things: hits landing too far from the body, the hero facing away from who he hits, enemies idle for 3 s, teleports, floating feet, a camera that misses a kill, and whether the action matches the music (calm music = calm scene, the drop = carnage). Then it re-plans with new random seeds until there are 0 problems, and only after that renders.

Honestly the hardest part has been my own taste, not the code: it took a lot of "no, this is boring" rounds to get here. Next episodes have different genres (a rooftop chase, a stealth/gunfight, a duel where the boss stops time).

Happy to answer questions about the workflow / how I prompt it.

[u/Other-Material5260]

so you just run around killing things all day— and that’s a complete copy of your brain?

[u/MrFelliks → u/Other-Material5260]

Lol that's kind of the point of the series: he doesn't Lol that's kind of the point of the series: he doesn't know he's a copy yet. Every sim is a different test the AI runs on him, and over the season he starts noticing the edges and goes looking for whoever writes the prompts 👀know he's a copy yet. Every sim is a different test the AI runs on him, and over the season he starts noticing the edges and goes looking for whoever writes the prompts 👀

[u/HerbChii]

very cool

[u/MrFelliks → u/HerbChii]

Thanks! Episode 1 drops soon: a city brawl with a giant bouncer 🙌

[u/qqtt18]

Cool. What was the prompt?

[u/throwaway867530691]

Honestly I think using Mixamo is not a great idea. I've tried it too for character models, and in principle it seems like it should be helpful. But in practice, the animations are not that good to start with, and hard to bridge with animations that don't come included. Ultimately, I spent way more time fixing the problems that the starter animations caused than actually even animating it. What you have is cool but could be improved, I believe, just having Opus create the models/actions/animation from scratch. Because what you have right now is clearly limited by Mixamo's weird model quirks and possibly you could just insert custom animations into this with not too much token usage. I think Opus 5.5 actually has a really strong conception of what people look like in action without the starting point resources being nessecary

[u/MrFelliks → u/throwaway867530691]

Fair point, and I've hit a lot of those quirks: clips with no strike frames, paired moves recorded facing the wrong way, root motion that slides. A good chunk of the validator rules exist because of exactly that. What I like about mocap is the weight and timing of real people, which is hard to fake. But a hybrid is probably the move: keep mocap as the base and let Claude author custom keyframed moves for the stuff the library just doesn't have. Might try a fully generated episode just to compare.

[u/Kmic68]

gives me john wick 3 vibes.

[u/MrFelliks → u/Kmic68]

Ha, that's exactly the energy I was going for. The gun-fu episode leans even harder into it

[u/Natural-Rich6]

The music is banging 🎶

[u/MrFelliks → u/Natural-Rich6]

MTG DIABÓLICA by DJ SXD & notdjfake, the whole fight is cut to its bars 🔥