Anthropic has officially launched its latest family of AI models, named Fable 5, which is derived from a previously classified military system known as Mythos. This technology was previously restricted to select tech giants.
The Fable 5 models were developed under a secret defense initiative called Project Glasswing, which had previously granted access only to specialists at Apple, NVIDIA, and the White House, aimed at safeguarding software from large-scale cyberattacks.
In internal tests, Fable 5 has shown remarkable superiority over its competitors, outperforming not only Anthropic’s previous flagship model, Opus 4.8, but also the latest offerings from OpenAI, GPT-5.5, and Google’s Gemini 3.1 Pro.
Comparison of Fable 5 and Mythos 5 capabilities with other leading AI models (screenshot: Anthropic)
Key technological advancements of Fable 5 include:
- Exceptional Computer Vision: The AI can recognize complex scientific graphs and intricate interface details, with real-time screen change detection.
- Image-Based Programming: The algorithm can recreate the source code of web applications or sites using just a few standard screenshots.
- Large Document Analysis: The model demonstrates greater efficiency with longer and more complex tasks compared to older AI services.
To showcase its visual capabilities, developers had Fable 5 complete the iconic game Pokémon FireRed without any text prompts or built-in navigation tools, relying solely on visual analysis.
Due to its powerful capabilities, the developers have implemented strict security filters. If users inquire about sensitive or potentially dangerous topics, the system automatically redirects their queries to the less advanced Opus 4.8 model.
Currently, the protective algorithms operate in a “conservative” mode, leading to approximately 5% of sessions where the AI may mistakenly block entirely benign inquiries.
Additionally, Anthropic has announced an even more powerful version, Mythos 5, which is free from civilian safety restrictions and capable of designing new drugs and chemical compounds. Notably, this algorithm will only be available to vetted corporations through a special trust program.
For regular users and subscribers of the Claude service, access to Fable 5 will remain completely free until June 22. After this date, the company will introduce a pay-per-use model based on token consumption.
In the future, once server capacity can handle the load, developers promise to revert the model to standard pricing plans without additional charges.
Anthropic has launched Fable 5, a new AI model based on a secret military system, showcasing superior capabilities over existing technologies. The company has implemented strict security measures and plans to introduce a paid model after a free access period.