Claude Mythos 5.2

Anthropic launched Claude Fable 5.2 and Claude Mythos 5.2, built around one model with two safeguard levels: Fable 5.2 runs classifiers that block high-risk cyber and research-biology requests and routes them to Opus models, while Mythos 5.2 drops those blocks and is limited to vetted organizations. On FrontierCode 2.0, Fable 5.2 scores 49.1% at Xhigh effort versus 45.5% for Opus 5.5 and 42.8% for GPT-6 Astra, and at High effort it matches Opus 5.5's best score at roughly half the cost per task, though Gemini 4 Carbon still leads AutomationBench and all figures are self-reported. Pricing is $8/$40 per million tokens with a 1M-token context window and 128K output, plus a fast mode up to 2.5x faster.

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, claiming notable gains across coding, reasoning, scientific research, cybersecurity and robotics, with up to 30% faster output and 20% lower cost. Fable 5.2 scored 49.1% on the agentic coding benchmark FrontierCode 2.0, beating GPT-6 Astra at 42.8% and Gemini 4 Carbon at 41.1%, and also led on multidisciplinary reasoning tests. Anthropic demonstrated it coordinating over 1,000 agents over eight days to build a bootable operating system from scratch.

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, with Fable 5.2 taking first place on the Code Arena WebDev leaderboard at 1832 points, ahead of Claude Opus 5.5, Gemini 4 Carbon and GPT-6 Astra. Anthropic claims up to 30% faster performance than Fable 5.1 and lower pricing of $8/$40 per million tokens.

Anthropic launched Claude Fable 5.2 and Mythos 5.2 on a shared base model, with Fable for general users and Mythos restricted to vetted cybersecurity and life-science institutions. API pricing drops 20% versus the prior generation and generation speed rises up to 30%, while pre-release tests included 1,000+ sub-agents building a bootable OS prototype from scratch in eight days.

Anthropic released Claude Fable 5.2 and Mythos 5.2 ahead of its IPO push, demoing over 1,000 agents working around the clock for eight days to autonomously write a bootable operating system with kernel, drivers, filesystem and installer from an empty folder. The model generates 30% faster and cuts API pricing 20% to $8 input and $40 output per million tokens, with an optional 2.5x Fast mode; Anthropic deliberately capped recursive self-improvement at Opus 5.5 level during training.

Anthropic released two flagship models, Claude Fable 5.2 and Mythos 5.2, targeting the most demanding technical tasks just ahead of its IPO. Fable 5.2 tops the Artificial Analysis Intelligence Index v5 with 65 points, five ahead of Gemini 4 Carbon and 15 above its predecessor Fable 5.1, while still leading at lower compute tiers with 62 points and far fewer tokens. Anthropic says it deliberately withheld capabilities that could directly accelerate AI development.

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, claiming gains in coding, reasoning and vision. Early observations report 10-12 hour autonomous work sessions, a jump from 21% to 41% on real freelance tasks in a single release, and orchestration of 1,000+ subagents. If accurate, this marks a step change in long-horizon agent autonomy and large-scale multi-agent coordination.

Anthropic announced that Claude Fable 5.2 and Claude Mythos 5.2 are now generally available on Amazon Bedrock and Claude Platform on AWS. Fable 5.2 is positioned as Anthropic's most capable generally available model for coding and science, able to handle ambiguous multi-step work, self-verify, and run unattended for hours to days, while Mythos 5.2 is gated behind verification programs for cybersecurity and life sciences.

Anthropic has launched Claude Fable 5.2 and Claude Mythos 5.2, claiming gains in coding, reasoning and vision for tackling demanding technical work. Fable 5.2 is now live in Arena's Agent Arena and Code Arena, where it can use web search, filesystem and terminal tools on long-horizon agentic tasks, with leaderboard scores to follow.

Anthropic launched Claude Fable 5.2 and Claude Mythos 5.2, its top-tier models, claiming roughly a one-tier gain over Opus 5.5 across nearly all tested capabilities, up to 30% faster output, and API pricing cut from $10/$50 to $8/$40 per million input/output tokens. Fable and Mythos are the same model differing only in guardrails: Fable is open to all paid users, while Mythos is restricted to vetted cybersecurity and life-science institutions. Pro subscribers get temporary plan-quota access to Fable from November 9 to 16.