Claude Fable 5.1 (Anthropic)

Anthropic released Claude Fable 5.1 on September 1, 2026, describing it as the company's most capable model for coding and knowledge work. The closed-weights model exposes a 1M-token context window, 128K max output tokens, and adaptive thinking with five effort levels: low, medium, high, xhigh, and max. Primary use cas Pricing is set at $10 per million input tokens and $50 per million output tokens, with cache reads cut 75% to $0.25 per million tokens compared to Fable 5; the Batch API offers a 50% discount. Subscription tiers include Pro at $17-20/mo, Max from $100/mo, Team at $30/seat/mo, and Enterprise at $20/seat/mo plus API usag

Anthropic launched Claude Fable 5.1 alongside Claude Mythos 5.1 on 1 September 2026, positioning Fable 5.1 for long-horizon agentic work — tasks that require planning, tool use, result examination, strategy adjustment, and continued autonomous operation. Mythos 5.1 shares the same underlying model with different safegu According to the article, Fable 5.1 ships with a 1M-token context window and 128K maximum output, accepts text and images, and uses adaptive thinking by default. Anthropic says typical token-billed workloads could cost around 25% less than Fable 5, with highly agentic workloads approaching 45% savings, primarily becaus

Anthropic released Claude Fable 5.1 alongside Claude Mythos 5.1 on 1 September 2026, framing both as the world's most advanced models for coding and knowledge work. The launch explicitly targets three customer pain points: price, data retention, and over-sensitive safeguards. Anthropic's published benchmark numbers sho Headline token pricing is unchanged at $10 per million input and $50 per million output, but cache reads are cut 75% to $0.25 per million, which Anthropic estimates translates to roughly 25% real-world cost reduction on typical workloads and up to 45% on step-heavy agentic work that repeatedly re-reads cached context.

AWS published a "What's New" entry for Claude Fable 5.1 in September 2026, confirming that Anthropic's new model is available on Amazon's cloud platform under the URL path /about-aws/whats-new/2026/09/claude-fable-5-1-aws/. The supplied scrape is dominated by AWS's cookie and preference banner text, so the excerpt itse For teams already running Claude workloads on Amazon Bedrock or other AWS services, the AWS listing is the clearest supplied signal that Fable 5.1 is available for deployment on AWS, complementing the API and Claude Platform availability reported by other sources. Any specifics about Bedrock region rollout, inference p

BenchmarkList aggregates eval results for Claude Fable 5.1, comparing it against Claude Fable 5, Claude Opus 5, GPT-5.6 Sol, GPT-5.6 Terra, Kimi K3, and Qwen3.8 variants. Reported scores include a GDPval-AA Elo of 1,853 at max reported effort (with effort-scaled scores from 1,587 at low to 1,853 at max), 87.7% at max e The page organizes results across agentic, reasoning, coding, and knowledge work categories, positioning Claude Fable 5.1 above its predecessor on long-horizon knowledge work (AA-Briefcase) and on the DRACO research agent benchmark. Effort-level scaling is a recurring theme, with multiple benchmarks reporting distinct

Claude Fable 5.1 is Anthropic's Mythos-class frontier model released on 1 September 2026, targeting demanding reasoning and long-horizon agentic workloads. It provides a 1M-token context window, up to 128K output tokens, and accepts text and image inputs, with adaptive thinking always on and an effort parameter default Pricing holds at Claude Fable 5's headline rates of $10 per million input tokens and $50 per million output tokens, but cache reads fall 75% to $0.25 per million; Anthropic estimates roughly 25% lower cost on typical workloads and up to about 45% on complex coding and agentic tasks. A 5-minute cache write is $12.50 per

An AI/TLDR daily digest entry for September 1, 2026 reports that Claude Code 2.1.257 switches its default Fable model to Claude Fable 5.1 and tightens auto mode by no longer waving through container-escape moves. The same digest highlights Claude Fable 5.1 as Anthropic's new top-end model, noting that the $10 input and For developers, this is concrete evidence that Claude Fable 5.1 reached Anthropic's own Claude Code tooling on launch day, becoming the default Fable model in the 2.1.257 release, and that the same release added a security behavior change around container-escape handling in auto mode. The digest does not itself provide

Anthropic officially launched Claude Fable 5.1 on September 1, 2026, alongside Claude Mythos 5.1, with positioning focused on coding and knowledge work. The model is available through the API and Claude Platform, is selectable in Claude Code, and was reported as available in Cursor and Claude on launch day. Confirmed h The retrospective compares what the pre-launch evidence predicted against the official documentation. Correct predictions include unchanged headline pricing and a focus on long-horizon reasoning and agentic work. Open questions flagged include independent benchmark validation, exact rollout scope across platforms, and