All tags
Model: "claude-mythos-5"
Anthropic Claude Fable 5
claude-fable-5 claude-mythos-5 claude-opus-4.8 gpt-5.5 anthropic cursor_ai cognition benchmarking software-engineering knowledge-work scientific-research vision context-windows model-pricing sdk rate-limiting mikeyk scaling01
Anthropic released two major models: Claude Fable 5 for general availability and Claude Mythos 5 for restricted access, with fallback to Claude Opus 4.8 for sensitive queries. Fable 5 features a 1M-token context window and pricing at $10/million input tokens and $50/million output tokens. It leads benchmarks in software engineering, knowledge work, scientific research, and vision, outperforming GPT-5.5 and setting new state-of-the-art scores on CursorBench, FrontierCode, Terminal-Bench 2.1, and Artificial Analysis Intelligence Index. The rollout includes Pro, Max, Team, and Enterprise plans with temporary usage credits due to capacity constraints. Middleware SDK support is available in Python, TypeScript, Go, Java, and C#.