What is the difference between Fable 5.1 and Mythos 5.1?

Fable 5.1 can't be used for sensitive cybersecurity and biology tasks, while Mythos 5.1 doesn't block such use cases and is accessible to only a limited number of trusted organizations.

How much does the Lambda deal cost?

Anthropic leased $35 billion worth of infrastructure from Lambda, with capacity estimated between 350 and 437 megawatts.

Large Language ModelsAI Business & IndustrySiliconANGLE AISep 1, 2026Sep 2, 2026, 06:00 JST

Anthropic launches Claude Fable 5.1 after $35B Lambda deal

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3 Key Points

What happened
Anthropic PBC debuted Claude Fable 5.1 and Claude Mythos 5.1, its most capable large language models to date. Fable 5.1 is generally available, while Mythos 5.1 is limited to trusted organizations.
Why it matters
Fable 5.1 set records on benchmarks, scoring 52.6% on Terminal-Bench-Science 0.1, more than double the previous model. It also scored 13% higher on Terminal-Bench 4.0, and its relaxed guardrails let researchers discover software vulnerabilities.
What to watch
Anthropic signed a $35 billion infrastructure deal with Lambda, following a $45 billion deal with Nscale. Improved prompt caching makes Fable 5.1 run typical workloads 25% more cost-efficiently, with savings up to 45% for AI-agent-heavy apps.

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Context & Analysis

The launch of Claude Fable 5.1 comes amid massive infrastructure investments by Anthropic. The day before the model debut, the company signed a $35 billion deal with Lambda, following a $45 billion contract with Nscale. These deals suggest Anthropic expects its computing needs to grow, even as it reduces hardware usage through prompt caching. The Lambda infrastructure will be housed in a data center built by Hut 8 in Texas, with Nvidia holding the lease, a structure that may reduce financial risks for the parties involved. The first data hall is expected to come online in late 2027.

FAQ

What is the difference between Fable 5.1 and Mythos 5.1?: Fable 5.1 can't be used for sensitive cybersecurity and biology tasks, while Mythos 5.1 doesn't block such use cases and is accessible to only a limited number of trusted organizations.
How much does the Lambda deal cost?: Anthropic leased $35 billion worth of infrastructure from Lambda, with capacity estimated between 350 and 437 megawatts.

SiliconANGLE AIRead Original Article

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