Artificial Analysis@ArtificialAnlys · XClaude Fable 5 发布即位列 Artificial Analysis Intelligence Index 第一，得分 64.9，领先第二名的 GPT-5.5 约 5 分。该模型采用自适应推理（最大努力模式）并以 Opus 4.8 作为回退模型。在 AA-Omniscience 知识测试中得分 40，领先此前最高分的 Gemini 3.1 Pro Preview 7 分；HLE 得分 53%，领先 Opus 4.8 超 7 个百分点。约 9% 任务触发安全护栏并回退。定价 $10/$50 每百万输入/输出 token（Opus 4.8 的两倍），缓存读写 $12.50/$1；上下文窗口保持 1M token。通过 Pro、Max、Team 等计划可用至 6 月 22 日，之后需消耗积分。
Claude Fable 5 launched today at #1 on the Artificial Analysis Intelligence Index， putting Anthropic nearly 5 points ahead of any other lab's best model
We supported @AnthropicAI with pre-release evaluation of Claude Fable 5. Claude Fable 5 scores 64.9 on the Artificial Analysis Intelligence Index， claiming the #1 rank overall. It is ~5 points ahead of the closest non-Anthropic model （GPT-5.5）， and Anthropic models now occupy both of the top 2 places.
Key takeaways for Claude Fable 5 （adaptive reasoning with max effort and Opus 4.8 as fallback model）：
➤ New safety guardrails for Mythos-class models： Claude Fable 5 uses the same underlying model as Claude Mythos 5 for public usage， with additional guardrails for potentially-harmful cybersecurity， biology， chemistry， and distillation-related queries. We tested Fable 5 using Anthropic's new 'fallback' mechanism， which can route safety-flagged messages to Claude Opus 4.8. Anthropic states that fallback occurs in fewer than 5% of sessions on average， and we recorded fallback routing in ~8% of tasks across the Intelligence Index （mostly in scientific questions from evaluations like GPQA， AA-Omniscience and Humanity's Last Exam）
➤ State-of-the-art Intelligence： Claude Fable 5 takes the #1 position on the Artificial Analysis Intelligence Index， scoring 64.9 and setting the highest score on 5 of the 10 underlying benchmarks. On AA-Omniscience， our knowledge and hallucination benchmark， Fable 5 scores 40， +7 points over the previous leader， Gemini 3.1 Pro Preview， driven primarily by higher accuracy. We generally observe a strong relationship between AA-Omniscience accuracy and model size in open weights models， which suggests Fable 5 could be larger than previous public Anthropic models
➤ Frontier agentic capability： Claude Fable 5 is at the frontier across all three agentic evaluations in the Index： GDPval-AA （real-world work tasks）， Terminal-Bench Hard （agentic coding）， and Tau2-bench Telecom （tool use for customer service）. Its GDPval-AA Elo of 1932 is a significant jump from the previous leader， Claude Opus 4.8， further extending Anthropic's lead in agentic capabilities