Developers and AI enthusiasts say Anthropic may have quietly connected an unreleased model to Claude, even when users select the publicly available Opus 5.5. Anthropic has not confirmed anything, and the evidence so far is user-posted demos and screenshots.
The loudest voice is a developer who posts as Chetaslua on X. On October 11, 2026, he claimed a model called Claude Next is being tested inside Claude Code and makes Opus 5.5 "look primitive." Claude Code is Anthropic's tool for programming with Claude.
What testers say they saw
According to the Chinese outlet 36Kr, which reported on the claims, users report that even with Opus 5.5 selected, the output feels as if a different model has taken over. Guesses range from a new Opus, Opus 5.6, to Fable 5.5. Fable is another model line from Anthropic.
The most-shared demo is an animation of a person's whole life, from embryo to old age. 36Kr reports it ran for about 30 seconds and came from four lines of prompt and two hours of running time. It was drawn frame by frame using JavaScript, a common web programming language, rather than a video or image generator.
Chetaslua also posted a short film in the style of the anime director Makoto Shinkai. 36Kr says the process took 2.5 hours, and that apart from a few static images and the background music, the effects and transitions were driven by code. According to the report, the art direction and storyboard were chosen by Claude itself.
Chetaslua argues that code-based generation could soon outcompete dedicated image and video models. He also says Opus has never been trained on video or audio data. Those are his opinions, not measured results.
What is not confirmed
Anthropic has said nothing publicly. One review of the claims found no model ID, price list, documentation, model card or statement from Anthropic. Anthropic's shipped lineup that day was Claude Fable 5.1, Opus 5.5, Sonnet 5.5 and Haiku 5.5.
The "hidden routing" idea predates this week. Chetaslua and another user reported it on October 1, but their screenshots still showed the Fable 5.1 label. Kingy AI, a site tracking the rumour, noted that Chetaslua's earlier short film was attributed to Fable 5.5 by its author, who said he used code, Blender and an ElevenLabs API, and that the post gave no verifiable model ID. Blender is 3D software and ElevenLabs is a voice and audio service.
36Kr describes one informal test: set Opus 5.5 to high reasoning and ask whether it knows VoxelBench without searching the web. Testers treat a correct answer as a hint of the new model, but 36Kr says that alone cannot confirm which model is running.
36Kr also says silent upgrades are common practice for Anthropic, and that similar routing was suspected when Opus 5.2 appeared. That is the outlet's account, and the search results here do not independently confirm it.
Background and what comes next
Anthropic has been releasing quickly. Its app release notes list Opus 5.5 on September 22 and Sonnet 5.5 on September 28, and it announced Haiku 5.5 on October 7.
36Kr links the supposed new model to Anthropic's plans to go public, citing unnamed industry insiders. Anthropic confidentially submitted a draft S-1 registration statement to the US Securities and Exchange Commission on June 1, 2026. The company said this gives it the option to go public after the SEC completes its review. No source reviewed here ties the Claude Next claims to the IPO.
For now, the story rests on social media posts. An official release, model listing or statement from Anthropic would settle whether a new model exists or whether Opus 5.5 has simply been updated.
