Anthropic upgrades Claude with new Fable 5.1 model, details here
Anthropic says the model is up to 25% cheaper for typical workloads and up to 45% cheaper for highly agentic tasks.
- Three months after the original launch, Anthropic is enhancing Claude with its new Fable 5.1 model upgrade, which improves coding performance and problem-solving tasks while reducing costs across the API.
- Anthropic first released Fable 5 as its flagship Mythos-class AI model positioned above smaller models like Haiku, Sonnet, and Opus in the Claude lineup.
- Fable 5.1 will cost an estimated 25% less than Fable 5 for typical workloads, with savings reaching approximately 45% for highly agentic work. Anthropic says it "achieves similar or better results than Fable 5 at a much lower cost."
- Alongside the general release, Anthropic is launching Claude Mythos 5.1 for trusted access programs with specialized safeguards designed for cybersecurity and life sciences work.
- In testing by investment firm Millennium, Fable 5.1 found the cause of a rare crash that engineers had struggled to explain for years, demonstrating its root-cause problem-solving capability.
26 Articles
26 Articles
Claude Fable 5.1 watermark: It has a blind spot developers can’t ignore
Anthropic launched Claude Fable 5.1 on Tuesday with a statistical signature embedded in its generated text, but developers shouldn’t expect The post Claude Fable 5.1 watermark: It has a blind spot developers can’t ignore appeared first on The New Stack.
Anthropic releases Claude Fable 5.1 and Mythos 5.1, cutting cache read prices by 75%
Anthropic has released Claude Fable 5.1 and Mythos 5.1, the same model with different safeguards, cutting cache read prices by 75% and reporting 52.6% on a scientific research benchmark against 24.7% for its predecessor. Its outputs carry a watermark required by the EU AI Act, and the detection API is in private preview for eligible […] This story continues at The Next Web
Anthropic is launching a new version of its powerful Fable artificial intelligence model, which, according to the company, is better at programming and scientific tasks, besides being more economical — changes that it claims to have been made in response to customer feedback. The company reported that Fable 5.1, whose release forecast is still on Tuesday, is more competent in performing long and complex computer programming tasks, such as softwa…
Anthropic's Claude Fable 5.1 Raises the Bar for Agentic AI While Tightening the Guardrails
Anthropic released Claude Fable 5.1 for general use and Mythos 5.1 for vetted researchers on Sept. 1, 2026. The shared model delivers major gains in agentic coding, scientific research and long-horizon tasks while cutting typical costs 25% via cheaper cache reads and sharpening safeguards to reduce false positives by up to 60%.
Coverage Details
Bias Distribution
- 67% of the sources are Center
Factuality
To view factuality data please Upgrade to Premium
