Claude Fable 5: The first Mythos model is powerful, expensive, and heavily filtered
Quick Answer
This paper shows that Anthropic's Claude Fable 5, the inaugural model in the Mythos class, excels in benchmarks with a 95% SWE-bench Verified score but comes at a steep cost of $10 to $50 per million tokens.
Quick Take
Anthropic's Claude Fable 5, the inaugural model in the Mythos class, excels in benchmarks with a 95% Verified score but comes at a steep cost of $10 to $50 per million tokens. The model employs strict safety filters that block 9% of requests, alongside a new 30-day data retention policy affecting all contracts.
Key Points
- Claude Fable 5 leads benchmarks with a 95% SWE-bench Verified score.
- The model's cost is significantly higher, ranging from $10 to $50 per million tokens.
- Strict safety filters block approximately 9% of user requests.
- A new 30-day data retention policy applies to all contracts, including zero-data-retention ones.
Article Excerpt
From source RSS / original summaryAnthropic has released Claude Fable 5, the first model in its new Mythos class. It leads nearly every benchmark, including 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 on The Decoder.
Reader Mode unavailable (could not extract clean content).
Want this in your inbox every morning?
Daily brief at your local 8am — bilingual EN/中文, free.
More from The Decoder
See more →
OpenAI models now available on Amazon Web Services
OpenAI has launched GPT-5.5, GPT-5.4, and Codex on Amazon Bedrock, matching its own pricing. Currently, these models are available only in the US across commercial and government AWS regions, with usage contributing to existing AWS contracts.
