News The Decoder Jun 10
Claude Fable 5: The first Mythos model is powerful, expensive, and heavily filtered
By Maximilian Schreiner
84 score
AI Analysis
Building on yesterday's coverage of Fable 5's guardrails, Anthropic released Claude Fable 5, the first Mythos-class model, which leads nearly every benchmark including 95 percent on SWE-bench Verified but costs about twice as much as Opus 4.8. It comes with strict safety filters blocking roughly nine percent of requests and a controversial 30-day data retention policy that overrides zero-data-retention contracts.
Anthropic has released Claude Fable 5, the first model in its new Mythos class. It leads nearly every benchmark, including SWE-bench Verified at 95 percent, but costs twice as much as Opus 4.8 at 10 or 50 dollars per million tokens. Strict safety filters block about nine percent of requests, and a new 30-day data retention policy applies even to zero-data-retention contracts.
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Model ReleasesAnthropicAI SafetyFrontier Capabilities
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Anthropic has released Claude Fable 5, the first model in its new Mythos class. It leads nearly every benchmark, including SWE-bench Verified at 95 percent, but costs twice as much as Opus 4.8 at 10 or 50 dollars per million tokens. Strict safety filters block about nine percent of requests, and a new 30-day data retention policy applies even to zero-data-retention contracts.
The article Claude Fable 5: The first Mythos model is powerful, expensive, and heavily filtered appeared first o
Model ReleasesAnthropicAI SafetyFrontier Capabilities