Hidden Model Named Obsidian 3 Spotted at Number One in Cognition's FrontierCode 2.0 Data Ahead of Claude Opus 5.5 (opens the post on X)
Very likely Fable 5.5 found in FrontierCode 2.0: Cognitions data reveals a hidden model, "Obsidian 3," scoring 46.8% against #1 Opus 5.5’s 45.5%, and since it runs in the claude-code harness used exclusively by Claude models, its save to say its Fable 5.5.







