Anthropic Launches Claude Fable 5.1 With Lower Costs and Fewer False Positives

Anthropic today introduced Claude Fable 5.1 and Claude Mythos 5.1, which the company says are the "world's most advanced models for coding and knowledge work." According to Anthropic, Claude Fable 5.1 sets a new standard for coding, knowledge work, and long-running problem-solving tasks. It achieves similar or better results than Fable 5 at low or medium effort, and has much higher performance at higher effort tiers. It outperforms Fable 5, Opus 5, and OpenAI's GPT–5.6 Sol across multiple benchmarks. Fable 5.1 and Mythos 5.1 are the same model, but with different safeguard levels. Fable 5.1 is available to everyone, but Mythos 5.1 is limited to U.S. companies and individuals participating in Anthropic's trusted access programs. There's a new Life Sciences Verification Program that allows Mythos 5.1's advanced biology capabilities to be used for scientific research, with open enrollment for scientists coming soon. Safeguards for Fable 5.1 have been improved, and Claude Code users should see around 60 percent fewer cybersecurity false positives. Anthropic says Fable 5.1 can now be used to discover software vulnerabilities, but not develop exploits for them. Fable 5.1 includes invisible watermarking for text generated by Claude, and Anthropic is rolling out a detection API in a private preview. The API is available to eligible organizations as required by EU law. Fable 5.1 costs approximately 25 percent less than Fable 5 for typical workloads, and up to 45 percent for highly agentic work, because of a reduction in cache-read pricing. Base pricing remains the same. It is available today on all platforms. Popular StoriesClaude Code Adds Cross-Session Messaging on macOSAnthropic has updated Claude Code so that separate coding sessions can message each other directly, removing the need to manually copy context between Terminal windows. The company shipped the feature in Claude Code version 2.1.224, released on Friday for macOS and Linux. Two new tools power it: ListAgents, which finds other active sessions running on the Mac, and SendMessage, which delivers ...New Apple Watch Series 12 and Apple Watch Ultra 4 Features RevealedBloomberg's Mark Gurman today further outlined what to expect from the Apple Watch Series 12 and Apple Watch Ultra 4 set to be unveiled on September 9. While it was initially rumored that Touch ID may be coming to the Apple Watch this year, Gurman reiterated that he does not expect the Series 12 or Ultra 4 to have any major design changes compared to the current Series 11 and Ultra 3 models. ...Apple Caught Off Guard by AI Demand for Mac Mini and Mac StudioApple's unusually timed announcement of new Mac mini and Mac Studio models this week was driven by unexpectedly strong enterprise appetite for AI hardware, according to The Information. Apple normally releases new Mac models in the autumn, closer to October or November, making this week's announcement unusually early, falling just before the anticipated arrival of new iPhone models. The...