Anthropic dropped two new frontier AI models on Monday, Claude Fable 5.2 and Mythos 5.2.
According to the AI company, Fable 5.2 and Mythos 5.2 were designed to "tackle the most daunting technical challenges" and present "improvements in areas like coding, reasoning, and vision."
New frontier models from OpenAI, Google, Anthropic, and Meta have been released at a rapid clip in recent months, and the two new Anthropic models closely follow the release of Google Gemini 4 Carbon, Meta Muse Wonder, and OpenAI's GPT-6 Astra. On launch day, Claude Fable 5.2 claimed the top spot on the Artificial Analysis Intelligence leaderboard, previously held by Gemini 4 Carbon.
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Anthropic said that in pre-release testing, the models "designed three working electronic devices from scratch, solved two open problems in the physics of black holes...and formalized the proof of Fermat’s Last Theorem in 30 hours."
Fable 5.2 and Mythos 5.2 also generate these outputs 30 percent faster than their 5.1 predecessors and "communicate more clearly" than previous models, Anthropic said.
Fable 5.2 Benchmarks
Performance is up across the board with Fable 5.2 with benchmarks showing significant increases when compared to other AI models.
For example, Fable 5.2 scored a whopping 74.6 percent on Terminal Bench Science benchmark. This is a significant increase from the 52.6 percent of its predecessor. It even scores higher than OpenAI's GPT-6 Astra's 68.1 percent.
Fable 5.2 also scored a 74.2 percent on the Humanity's Last Exam benchmark, another increase over its predecessor's 65.6 percent.
Fable 5.2 and Mythos 5.2 pricing and availability
Pricing for the new models is also lower than their predecessors at $8 per million input tokens and $40 per million output tokens.
Fable 5.2 launches today for all Claude users. The company said that Fable 5.2 has "strong cybersecurity and biology safeguards to guard against misuse," which is why it's available to all users. Mythos 5.2, however, is only available for verified organizations working on cybersecurity or biomedical research.
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Disclosure: Ziff Davis, Mashable’s parent company, in April 2025 filed a lawsuit against OpenAI, alleging it infringed Ziff Davis copyrights in training and operating its AI systems.
