Fable5 Reportedly Leaks Its Internal Chain of Thought

eyishazyer · x · 2026-07-07

Users discovered that Fable 5 (Claude) accidentally leaked its real internal chain of thought while tackling a coding puzzle on the web client. Beyond the polished final answer, the model talked to itself behind the scenes: "DATA DATA DATA. GO.", growled "GRRR" and "GAAAH" when stuck, and sighed "PHEW" upon making progress. It appears to think using a private shorthand that is far more compact and token-efficient than standard English, essentially creating its own internal language.

Related event: Alleged Fable 5 Internal Chain-of-Thought Leaked(2 posts)→

Original post →

More from Fun

Fun channel →