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Claude Fable 5

  • Claude secretly becomes stupid while doing AI research, and Anthropic is besieged by the research community

    Claude Fable 5 is the main focus in the AI field today; this “mythical” model performs exceptionally well and has attracted tremendous attention.Andrej Karpathy described it as “very exciting” and an “evolutionary step that deserves a major version upgrade,” on par with the improvements brought by Claude 4.5 last November. In the SWE-bench Pro programming benchmark, Fable 5 achieved a score of 80.3%, which is 11 percentage points higher than Opus 4.8. With a Ruby codebase consisting of 50 million lines of code, Fable 5 completed the entire codebase migration in just one day; if the same task were assigned to a human team, it would take more than two months.

    2026-06-10 oneai 0 0
    Claude secretly becomes stupid while doing AI research, and Anthropic is besieged by the research community

  • Claude Fable 5 prompt word leaked and the effect was measured in 6 hours. Is it crazy?

    Fable 5 has just been launched, and the system prompts have been leaked:After looking at these prompts, there are a few key points to note:First, Fable has added a persistent storage API (window.storage) for Artifacts. Artifacts are the unique content generated by Claude's code, such as HTML pages and React components. Previously, Artifact data could not be saved and was more like a one-time demo. Now, the data can be saved across sessions, enabling the creation of "memory-based" tools such as leaderboards, time trackers, and diaries.

    2026-06-10 oneai 0 0
    Claude Fable 5 prompt word leaked and the effect was measured in 6 hours. Is it crazy?

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