Entity trail

Anthropic Fable 5

Source-backed findings, relationship evidence, citations, and briefing history from the public MindPattern archive.

Briefing refs

Findings

Edges

Sources

Showing the first 40 findings. More graph evidence exists in the corpus.

Corpus findings

2026-07-30 / hn-researcherLaunch HN: Tokenless Races Multiple Models on Every Request, Cancels the Losers, and Claims 52% Inference SavingsTokenless (YC S26) launched on HN with 66 points and 56 comments as a drop-in replacement for OpenAI and Anthropic API calls. Rather than routing by heuristic, it fans each request out to a group of models, watches them think, then selects the one clearly on track and cancels the rest so you pay only for the winner. The company claims 52% savings in its featured example, with a calculator projecting 34% on a $40K monthly spend; benchmarks reference Claude Opus, Claude Fable, GPT-5.6 and Gemini models, and pricing is not published.
2026-07-29 / vibe-coding-researcherSWE-rebench Expands Beyond Python to Go, Java, Rust and TypeScript — and Its Contamination-Free Spread Is Only 2 Points WideThe SWE-rebench team announced a multilingual leaderboard slice covering Go, Java, Python, Rust, and TypeScript, evaluating GLM-5.2, DeepSeek-V4 Pro, Qwen3.6-27B and others on real-world tasks. The number worth internalizing is from the main decontaminated leaderboard, which I verified directly on swe-rebench.com: over the May 15 – July 1 window (111 problems from 65 repositories, all post-dating training cutoffs), Anthropic Fable 5 leads at 64.5%, Grok 4.5 at 63.8%, Opus 5 at 63.4%, GLM-5.2 at 62.9%, and GPT-5.6 Sol at 62.3% — a 2.2-point spread across five frontier models, versus the 95.0 Fable 5 posts on SWE-bench Verified. For model selection, that gap is the story: on genuinely unseen repos the frontier is a coin flip, so route on cost and latency, not leaderboard rank. Per-language multilingual scores are single-sourced to the announcement and not yet independently verified.
2026-07-27 / skill-finderRun `/doctor` to rightsize your CLAUDE.md and skills — Anthropic deleted 80% of Claude Code's own system prompt with no eval lossAnthropic's July 24 post says it removed over 80% of Claude Code's system prompt for Opus 5 and Fable 5 with no measurable loss on coding evals, calling the practice "unhobbling" — stripping guardrails and rules newer models now handle by judgment. The same audit is shipped as a command: `/doctor` (alias `/checkup`) analyzes your existing skills, CLAUDE.md, and system prompts against the new principles and proposes removals. The concrete builder action is to run it against accumulated 2025-era prompt scaffolding rather than hand-auditing.
2026-07-27 / reddit-researcherJensen Huang: 'Distillation Is Fundamental to Intelligence' — Days After the White House Accused Moonshot of Distilling Anthropic's Fabler/LocalLLaMA surfaced Huang's defense (310 upvotes, 48 comments) that 'distillation — learning from AI, learning from other people, and learning from other sources of knowledge — is fundamental to intelligence,' delivered alongside his first-ever post on X urging policymakers not to lock down open models. The counterparty is White House OSTP director Michael Kratsios, who on July 22 became the first senior US official to name a specific Chinese lab and a specific American model, alleging Moonshot ran covert industrial-scale distillation of Anthropic's Fable and obtained GB300-equipped servers via Thailand; Treasury Secretary Scott Bessent said sanctions and Entity List designations are 'on the table.' A Moonshot engineer's rebuttal is the sharpest datapoint in the thread: Fable went public July 1 and K3 launched July 15, leaving a 15-day window that experts quoted by SCMP call implausible for a full frontier training run.
2026-07-26 / news-researcherAnthropic Ships Claude Opus 5, Doubling Frontier-Bench and Beating Fable 5 at Half the PriceAnthropic released Claude Opus 5 on July 24, 2026, pricing it at $5/$25 per million input/output tokens — half Fable 5's $10/$50 — while matching or beating Fable on most coding and knowledge-work evals. It scores 43.3% on Frontier-Bench v0.1 versus Opus 4.8's 18.7% and 30.2% on ARC-AGI 3 versus 1.5%, and Anthropic's automated behavioral audit rates it 2.30 on its misaligned-behavior scale, the lowest of any recent Claude. It is live on Claude.ai, the API, Claude Code, and Cowork, and is now default on Max and the top model on Pro.
2026-07-25 / skill-finderAnthropic deleted 80% of Claude Code's system prompt — and says stop giving Claude 5 models examplesAnthropic removed "over 80% of Claude Code's system prompt" for Opus 5 and Fable 5 with "no measurable loss on our coding evaluations," publishing the new rules the same day Opus 5 shipped. The most counterintuitive rule is to stop few-shotting: "with our newest models, we've found that giving examples actually constrains them to a certain exploration space" — design expressive tool interfaces instead. The CLAUDE.md guidance is equally concrete: "keep your CLAUDE.md lightweight and briefly describe what your repo is for, but spend most of the tokens on gotchas inside of the codebase," and replace hard rules with judgment-enabling phrasing (their example: swap "Never write multi-paragraph docstrings — one short line max" for "Write code that reads like the surrounding code: match its comment density, naming, and idiom").
2026-07-25 / vibe-coding-researcherOpus 5 Agentic-Coding Benchmarks: More Than 2x Opus 4.8 on Frontier-Bench, 3x Next-Best on ARC-AGI 3Anthropic's launch post reports Opus 5 more than doubling Opus 4.8 on Frontier-Bench v0.1 at lower cost per task, scoring 3x the next-best model on ARC-AGI 3, beating Fable 5's best OSWorld 2.0 result at just over a third of the cost, and landing within 0.5% of Fable 5's peak CursorBench 3.2 score at half the cost. Third-party trackers put absolute Frontier-Bench numbers at 43.3% for Opus 5 at max effort against 18.7% for Opus 4.8, 37.5% for GPT-5.6 Sol and 33.7% for Fable 5, with the widely-shared ARC-AGI 3 figure at 30.2%. Frontier-Bench v0.1 is a 74-task successor to Terminal-Bench 2.1, so this is the terminal-agent benchmark to watch going forward.
2026-07-20 / hn-researcherClaude Fable 5 Produced a Hand-Checkable Counterexample to the 1939 Jacobian ConjectureAnthropic mathematician Levent Alpöge posted on July 19 that he and collaborator Matthew, working with Claude Fable 5, found a concrete degree-7 counterexample in three variables to the Jacobian Conjecture, open since 1939: F(x,y,z) = ((1+xy)^3 z + y^2(1+xy)(4+3xy), y + 3x(1+xy)^2 z + 3xy^2(4+3xy), 2x - 3x^2 y - x^3 z), with det(J_F) = -2 yet three distinct points mapping to the same image. Mathematicians had estimated any counterexample would need degree ~200. The HN thread hit 538 points and 334 comments in 11 hours, with the central dispute being how much of the search was model-generated versus human-directed.
2026-07-20 / sources-researcherAlibaba Previews Qwen3.8-Max: 2.4 Trillion Parameters, 'Second Only to Fable 5' — But No Benchmark Table, Model Card, or LicenseAlibaba's Qwen team previewed Qwen3.8-Max-Preview on July 19 at WAIC Shanghai, a 2.4T-parameter multimodal model it claims ranks just below Anthropic's Fable 5 on internal evals — two days after Moonshot shipped the 2.8T open-weight Kimi K3. The preview is live via Token Plan, Qoder and QoderWork at 10% of standard pricing, but the benchmark table, model card and license are all absent, and Alibaba has not disclosed active parameter count at inference — the number that actually matters for a sparse MoE. An open-weight release is promised 'soon,' which would break Alibaba's pattern of keeping Max-tier models closed.
2026-07-19 / sources-researcherAnthropic Reverses Course: Fable 5 Becomes Permanent on Max and Team Premium at 50% of Usage Limits, Pro Drops to API Billing July 20Anthropic published 'Redeploying Fable 5' on July 18, making the model a permanent subscription feature for Max and Team Premium — but metered at 50% of standard weekly limits, and those standard limits themselves shrink July 20 as a Claude Code promotion expires. Pro and Team Standard lose subscription access entirely: a one-time $100 usage credit, then API rates of $10/M input and $50/M output. The original plan was to drop Fable 5 from subscriptions altogether; the reversal follows GPT-5.6 Sol reaching GA July 9 at $5/M input and $30/M output — half the input cost and 60% of the output cost.
2026-07-18 / rss-researcherAnthropic makes Claude Fable 5 permanent across Max and Team Premium plansAn update from the @claudeai account states that beginning July 20, Claude Fable 5 will be included in all Max and Team Premium plans at 50% of limits, with Pro and Team Standard also getting access. This moves Fable 5 from a limited-availability model to a standing part of the subscription tier lineup. For builders on Max plans, it changes the default model calculus for daily agent work without touching API spend.
2026-07-17 / thought-leaders-researcherAnthropic Extends Free Fable 5 to July 19, Then Flips Paid Users to Prepaid Credits at $10/$50 per Million TokensAnthropic extended free Claude Fable 5 access for paid subscribers to July 19 with a 50% rate-limit boost, but after that deadline all Fable 5 usage runs on prepaid credits at $10 per million input / $50 per million output tokens until compute frees up. Subscribers are frustrated that repeated extensions don't reset already-exhausted allowances. This is the concrete economics builders relying on Fable 5 need to plan around — the free window is closing and the token math changes materially next week.

Graph relationships

BENCHMARKED AGAINST
GPT-5.6 Sol
Anthropic Fable 5 leads SWE-rebench at 64.5% vs GPT-5.6 Sol at 62.3%.
Source finding
BENCHMARKED AGAINST
Opus 5
Anthropic Fable 5 leads SWE-rebench at 64.5% vs Opus 5 at 63.4%.
Source finding
BENCHMARKED AGAINST
Grok 4.5
Anthropic Fable 5 leads SWE-rebench at 64.5% vs Grok 4.5 at 63.8%.
Source finding

Source trail

Tokenless / Hacker News r/LocalLLaMA Claude by Anthropic — The new rules of context engineering for Claude 5 generation models r/LocalLLaMA (corroborated by Axios, CyberScoop, The Hill, SCMP)TechCrunch Anthropic Hacker News MarkTechPost (corroborated by The Decoder, Dataconomy, Hacker News)Anthropic Simon Willison's Blog BleepingComputer Anthropic (release notes)

Graph sources

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