Unverified: Chetaslua Says Anthropic's Fable 5.5 Made a 66 Second Animated Short Entirely in Python Code, With No Image Models
Fable 5.5 its over for video and image models 🤯 THIS IS PURE CODE one shotted this video holy shit , how this is more beautiful than ai video models Two ways to check this yourself: Ask: “Where did @karpathy go in 2026?” with web search and memory turned off. Only the new Fable knows the answer. Then give it the prompt. Run the same prompt I used for the test (it’s in the screenshot) and see for yourself. Don’t rely on Grok for basic reasoning like this. Grok doesn’t have up-to-date knowledge of niche stuff. Either join the community or run the test yourself. Also, a knowledge cutoff doesn’t mean a model knows everything before that date. Sometimes a model doesn’t know about an event even if it happened before its cutoff. This test shows that too. Run the same prompt on regular Opus 5.5 and the quality drops. On Fable 5.1 it’s worse.
Context
If a coding model can write a polished animated film with its own music in one go, the line between code generation and video generation starts to blur.
Fable is a Claude model line, and unconfirmed leaks since mid October have said a Fable 5.5 checkpoint is being tested. Anthropic has not announced Fable 5.5. Chetaslua (@chetaslua) is an AI tester who posts early model demos, and Chubby (@kimmonismus) reshared the video.
Deep dive
Chetaslua (@chetaslua) posted on Nov 2 a short animated film he says was made entirely in code by Fable 5.5, writing that it is over for video and image models. He says the model one shotted the video.
In a follow up post, he gave more detail. He says Fable 5.5 made a 66 second animated short with zero image models, and that every frame and every sound is Python the model wrote itself, including a fox, paper birds, clouds, lettering, a score and sound effects. He lists the output as 1920 by 804 pixels at 24 frames per second in a single HTML file, with no generated images, stock assets, samples or font files, and about 2 hours 40 minutes of autonomous work. He adds that it is not Ghibli level, and that the model told him so.
The key question is which model made it. Chetaslua offers two tests: ask the model where Andrej Karpathy went in 2026 with web search and memory off, which he says only the new Fable knows, or run the same prompt shown in his screenshot. He says regular Opus 5.5 produces lower quality and Fable 5.1 is worse. Chubby (@kimmonismus) reshared the video and called it most likely the latest Fable 5.5 checkpoint.
None of this is confirmed. Anthropic has not announced Fable 5.5 or said which models are in testing, the knowledge test is indirect, and the code itself has not been published for others to check. The video is real, but the model behind it is a claim by the poster.
What to expect next
Watch for Anthropic to announce Fable 5.5 or publish a model card, and for other testers to reproduce the film from the same prompt. Publishing the HTML file would let others confirm it is pure code. If confirmed, expect more demos of coding models producing animation, games and music, and new debate over how they compare with dedicated video models.