Anthropic Claude Fable 5

Caylent's piece positions Claude Fable 5 as Anthropic's most capable generally available model and the first publicly available entry in a new "Mythos-class" tier above Opus. It outlines the launch chronology: Anthropic completed training of Mythos on April 7, 2026, withheld general release, then shipped Fable 5 to the The article frames Fable 5's value proposition around capability gains versus deployment economics, noting $10/$50 per-million-token pricing and a safeguard layer that routes some requests to Opus 4.8. It discusses where the capability lead matters for enterprise adoption and the conditions under which the new tier is

ComputingForGeeks details the June 9, 2026 release of Claude Fable 5 as the first public model sharing weights with Mythos, the internal system whose cybersecurity capabilities prompted restricted release. It explains the two-models-one-weights structure: Mythos 5 is the unsafeguarded twin under Project Glasswing for v The piece documents that Fable 5's safeguards fall back to Opus 4.8 in under 5% of sessions, with the fallback opt-in on the raw API. It covers the exact model ID (claude-fable-5), pricing tiers, and how to invoke the model from both the API and Claude Code, providing an API/developer implementation angle on the releas

BuildFastWithAI confirms the June 9, 2026 launch of Claude Fable 5 as the first publicly available Mythos-class model, with the API identifier claude-fable-5, a 1 million token context window, and up to 128k output tokens per request. It states the model is priced at $10 per million input tokens and $50 per million out The piece characterizes Fable 5 as Mythos made accessible for public use, sharing weights with the restricted Mythos 5 but with guardrails enabled. It includes an anecdotal claim that Stripe ran a 50-million-line Ruby codebase migration in one day using Fable 5, presented as evidence of the model's capacity for large-c

Thesys describes Claude Fable 5 as Anthropic's newest generally available frontier model, built on the same underlying architecture as Mythos 5 with safeguards primarily covering cybersecurity and biology-related queries. It reports Fable 5 scores 80.3% on SWE-Bench Pro, outperforming Opus 4.8 and GPT-5.5 across many c The blog frames Fable 5 as a candidate for production-grade agent deployments, since outside the safeguarded categories it performs equivalently to Mythos 5. It positions the benchmark gaps between Fable 5, Opus 4.8, and GPT-5.5 as meaningful for teams choosing a model to build agents around, with caveats that teams in

Artificial Analysis's changelog for September 1, 2026 documents Claude Fable 5.1 Intelligence Index results across all five Adaptive Reasoning effort levels when served via DigitalOcean's endpoint: Low effort scores 58, Medium 60, High 62, Xhigh 65, and Max 66, providing independent provider-specific reasoning trade-of The same changelog notes that Claude Fable 5.1 tops the Artificial Analysis Intelligence Index at max effort with a score of 66 and leads on agentic knowledge work, and it also lists new Anthropic and DigitalOcean performance entries alongside other provider results from SambaNova, Databricks, CoreWeave, Multiverse Com

DigitalOcean announced on September 1, 2026 that Claude Fable 5.1, a point release on Anthropic's Claude Fable 5, is now available through the DigitalOcean Inference Engine via Serverless Inference, with no separate Anthropic account or contract required. The release integrates with DigitalOcean's Inference Router for The DigitalOcean blog reports concrete benchmark gains for Fable 5.1 over Fable 5: Terminal-Bench 4.0 rises to 55.8% (from 42.0%), CursorBench 3.2.0 to 73.4% (from 70.5%), GDPval-AA v2 to 1,853 (from 1,723), AutomationBench to 31.4% (from 17.1%), and Humanity's Last Exam without tools to 60.9% (from 57.8%). Cache-read