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Anthropic says Fable 5.1 will cost an estimated 25% less than Fable 5 for typical workloads and up to 45% less for highly agentic work (Zac Hall/9to5Mac)

ThinkingNews Desk · how this was written

Anthropic has launched Claude Fable 5.1, which is generally available, alongside Claude Mythos 5.1 for trusted partners with added cybersecurity and life-sciences safeguards. Fable 5.1 is priced roughly 25% lower for typical workloads and up to 45% lower for highly agentic tasks, while cache-read costs are reduced by 75%. The update is touted to raise standards for coding, knowledge work and long-running problem-solving, and to address root causes of software issues.

Written from all 6 reports below, not from any single one.

How it was reported

  1. Hacker News·
    What's new in Claude Fable 5.1

    Claude Fable 5.1 keeps the same price as Claude Fable 5, reduces cache-read costs to 25%, and adds long-running agentic coding, multistep research, plus document, spreadsheet, and slide generation with a 1 million-token context window and 128 k max output. It enforces automatic tool selection (forced tool use returns a 400 error), always enables adaptive thinking controllable via an effort parameter, and retains thinking blocks only when advancing to newer models; editing prior turns invalidates those blocks. Claude Mythos 5.1 matches these specs and pricing but is restricted to Project Glasswing participants.

  2. Hacker News·
    Claude Fable 5.1 and Claude Mythos 5.1

    Claude Fable 5.1 and Claude Mythos 5.1 are the same AI model with different safeguard tiers; Fable 5.1 is generally available at roughly 25% lower cost than its predecessor, while Mythos 5.1 is restricted to trusted-access programs for cybersecurity and life-science work. Both incorporate Enterprise Frontier Safeguards that enforce zero data retention and cut false-positive rates by 60% in cybersecurity, and they outperform prior versions in coding, knowledge work, and scientific research, including identifying a long-standing software crash and supporting molecular-design projects.

  3. TechMeme·
    Anthropic unveils Claude Fable 5.1, which is generally available, and Mythos 5.1, for trusted partners and with cybersecurity and life sciences safeguards (Anthropic)

    Anthropic announced the general-availability of Claude Fable 5.1, a model optimized for coding and knowledge-work tasks, alongside Claude Mythos 5.1, which is limited to trusted partners and includes built-in cybersecurity and life-sciences safeguards. Both models represent Anthropic’s latest advancements in AI capabilities.

  4. TechMeme·
    Anthropic says Fable 5.1 will cost an estimated 25% less than Fable 5 for typical workloads and up to 45% less for highly agentic work (Rachel Metz/Bloomberg)

    Anthropic has launched Claude Fable 5.1 as a general-availability model and Claude Mythos 5.1 for trusted partners, adding cybersecurity and life-sciences safeguards. The company estimates Fable 5.1 will cost roughly 25% less than Fable 5 on typical workloads and up to 45% less on highly agentic tasks, while its new Enterprise Frontier Safeguards let businesses dictate data review, storage, and management.

  5. VentureBeat·
    Anthropic's Claude Fable 5.1 and Mythos 5.1 arrive with a 75% cost reduction for Fable cache reads

    Anthropic launched Claude Fable 5.1 (general-availability) and Claude Mythos 5.1 (restricted-access), the same model with different safeguards, and reduced cached-context costs by 75%. Enterprise Frontier Safeguards enable on-prem monitoring. Fable 5.1 scored 52.6% on Terminal-Bench-Science 0.1, 55.8% on Terminal-Bench 4.0, 1,853 on GDPval-AA v2, 31.4% on AutomationBench, and 73.4% on CursorBench 3.2.0; Mythos 5.1 achieved 60.9% on the coding benchmark. Early-access users reported the model fixing a long-standing software crash, running 38-hour ML experiments autonomously, and completing 82% of tasks on a demanding browser-agent benchmark.

  6. TechMeme·
    Anthropic says Fable 5.1 sets new standards on coding, knowledge work, and long-running problem-solving tasks, and can fix the root causes of software issues (Carl Franzen/VentureBeat)

    Anthropic announced the general-availability launch of Claude Fable 5.1 and the partner-only Claude Mythos 5.1, which it touts as the most advanced models for coding, knowledge work, and long-running problem-solving, capable of identifying and fixing root causes of software issues. Mythos 5.1 includes additional cybersecurity and life-sciences safeguards for trusted partners.

  7. TechCrunch·
    Anthropic’s new Fable release is cheaper, less restrictive

    Anthropic released upgraded flagship models Fable 5.1 and Mythos 5.1, cutting token costs and decreasing false-positive safety blocks. Fable 5.1 is unrestricted and accessible via cloud or API; Mythos 5.1 is limited to cybersecurity and life-science partners. Both support zero-data-retention deployment and a phased rollout of Enterprise Frontier Safeguards, achieve new benchmark records on Terminal-Bench 4.0 and Humanity’s Last Exam, and the system card notes Mythos 5.1 is slightly more prone to misbehavior than Opus 5 while improving on prior Mythos versions.

  8. The Next Web·
    Anthropic releases Claude Fable 5.1 and Mythos 5.1, cutting cache read prices by 75%

    Anthropic launched Claude Fable 5.1 and Mythos 5.1, identical models differentiated only by safety layers, with cache-read costs reduced 75% to $0.25 per million tokens, lowering typical workloads by ~25% and agentic workloads up to 45%. Fable 5.1 achieved 52.6% on Terminal-Bench-Science 0.1 and 55.8% on Terminal-Bench 4.0, versus 24.7% for its predecessor, and its outputs embed an EU-mandated watermark detectable via a private-preview API for approved organizations.

  9. The Verge·
    Anthropic launches Claude Fable 5.1 and says it’s up to 45 percent cheaper for agentic work

    Anthropic released Claude Fable 5.1 and Mythos 5.1, noting that Fable 5.1 outperforms its predecessor while averaging a 25% cost reduction and up to 45% savings on complex agentic tasks thanks to cheaper cached-data pricing. The models address concerns about price, data retention and restrictive safeguards, and early user Dan Shipper of Every CEO described Fable 5.1 as a fast, token-efficient coding model that “actually speaks like a norm.”

  10. TechMeme·
    Anthropic prices Fable 5.1 at $10/1M input tokens and $50/1M output tokens, unchanged from Fable 5, and cuts cache read pricing by 75% to $0.25/1M tokens (Frederic Lardinois/The New Stack)

    Anthropic announced that its Fable 5.1 model will be priced at $10 per million input tokens and $50 per million output tokens, identical to Fable 5, while reducing cache-read costs by 75% to $0.25 per million tokens. The company also highlighted that the new pricing applies uniformly across all usage tiers, aiming to lower operational expenses for developers integrating the model.

  11. TechMeme·
    Anthropic says Fable 5.1 will cost an estimated 25% less than Fable 5 for typical workloads and up to 45% less for highly agentic work (Zac Hall/9to5Mac)

    Anthropic has launched Claude Fable 5.1 for general use and Claude Mythos 5.1 for trusted partners, positioning them as its most advanced models for coding and knowledge work. The company claims Fable 5.1 reduces typical workload costs by roughly 25 percent and can cut costs up to 45 percent for highly agentic tasks.

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