Anthropic's unreleased fable 5.5 model showcases advanced code-based media generation capabilities

Early testing of Anthropic's forthcoming flagship model, Claude Fable 5.5, has surfaced in developer communities, demonstrating sophisticated autonomous coding abilities. One notable demonstration involved the model independently writing and executing code for nearly two hours and forty minutes to produce a 66-second animated short. This creation, shared by AI developer Chetaslua on November 2nd, featured elements like foxes, paper birds, and lighting effects, with the music and sound design also generated via Python code, all encapsulated in an HTML file. Unlike tools that directly render video, this showcased a code-driven animation pipeline, requiring no external assets. Furthermore, developers have shown Fable 5.5 generating interactive 3D scenes using technologies like Three.js, and in complex animation tests, Jazil's group noted Fable 5.5 could code and run dynamic scenes, such as character battles, in about an hour, outpacing some existing Claude models. Speculation around the model's release has been fueled by past sightings, including a brief listing of claude-fable-5-5 in the LiteLLM Azure directory in mid-October and the appearance of 'Claude Mythos 5.5' in Anthropic's website source code. While Fable and Mythos share a base model, Mythos is restricted to vetted research institutions. This development occurs as Anthropic moves toward an IPO, having reported $33.242 billion in revenue for the first three quarters of this year.