Anthropic Launches Claude Fable 5.2 and Mythos 5.2: Same Model, Different Safeguards

Anthropic released Claude Fable 5.2, a frontier model with a 1M-token context window and 128K max output, available only via hosted API on the Claude Platform, AWS, Google Cloud and Azure at $8/$40 per million input/output tokens. Mythos 5.2 is the same underlying model with fewer cyber and biology safeguards, gated behind Anthropic's Cyber and Life Sciences Verification Programs. Anthropic reports Fable 5.2 ahead of Opus 5.5 on most benchmarks it published, with about 55% fewer blocks than Fable 5.1.