GoKawiilAnthropic ships Claude Fable 5.1 and restricted Mythos 5.1 variant, slashes cached token costs 75%
Anthropic launched Claude Fable 5.1 across its API, cloud platforms and desktop app, alongside Mythos 5.1, a less-restricted version limited to vetted cybersecurity and life-sciences organizations. The company says Fable 5.1 handles multistep coding and scientific workflows more efficiently, using fewer tokens, and posted large gains on internal benchmarks like Terminal-Bench 4.0 and Terminal-Bench-Science 0.1 versus its predecessor.
GoKawiil's interpretation of the reporting above, not reported fact.
Cutting cached token pricing while boosting efficiency lowers the cost of running long-running AI agents, a major barrier for enterprises deploying models on sustained, multistep tasks. Splitting access into a general-purpose model and a gated, less-restricted one for trusted sectors shows Anthropic trying to balance capability with safety concerns around dual-use research areas like cybersecurity and biology. However, since the benchmark gains are self-reported, they can't yet be verified against rival models from OpenAI or Google.
- Fable 5.1 is publicly available while Mythos 5.1 is reserved for vetted cybersecurity and life-sciences partners
- Anthropic claims major benchmark jumps, including more than doubling scientific-agent performance over Fable 5
- Cached token pricing cut by 75%, aimed at making long-running AI agent workflows cheaper for businesses
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Published there as: “Anthropic releases Claude Fable 5.1, cuts cached token pricing by 75%”
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