Anthropic Releases Fable 5.2 and Mythos 5.2 Dual-Tier Models
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.
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▲ Marktechpost AI · 2026-11-10 15
▲ Anthropic just released Claude Fable 5.2 and Claude Mythos 5.2, an upgrade that beats Opus 5.5 on most of its own benchmarks at a lower price.
The key idea is 1 model with 2 safeguard levels. Fable 5.2 runs classifiers that block high-risk cyber and research-biology requests, then hands those to Opus 4.8 or Opus 5. Mythos 5.2 is the same model without those blocks, for vetted orgs only.
On FrontierCode 2.0, Fable 5.2 scores 49.1% at Xhigh effort, vs 45.5% for Opus 5.5 and 42.8% for GPT-6 Astra. At High effort it matches Opus 5.5's best score for roughly half the cost per task. It is a trade-off though: Gemini 4 Carbon still leads AutomationBench (53.9% vs 51.4%), and every score is self-reported.
Pricing is 40 per million tokens, with a 1M-token context window and 128K output. Fast mode runs up to 2.5x faster at 80. API ID: claude-fable-5-2......
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