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  1. Home
  2. Models
  3. Claude Fable 5
Updated Jun 9, 2026
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Openings

How Claude Fable 5 starts an answer

The first lines of 5 of its 24 written answers. Formatting stripped, words untouched.

Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

1,932 words
Architecture Review: Critical Issues & Solutions 🔴 Critical: Data Loss & Correctness Issues Client clock timestamps for conflict resolution Problem: Client clocks are unreliable—skew, drift, timezone bugs, and deliberate manipulation. A user with a clock 5 minutes fast will always win conflicts.
Read the full answer

Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

1,810 words
3-Month Precision Longevity Protocol A Phased Biohacking Program for Healthspan, Cognition & Performance Important caveat up front: Several elements below (rapamycin, metformin, peptides, high-dose supplements) require physician oversight and prescription.
Read the full answer

Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

1,567 words
Contract Analysis: Significant Contractor Risks Identified Disclaimer: This is general analysis, not legal advice. Have a licensed attorney in your jurisdiction review before signing. This contract is heavily one-sided. Nearly every clause shifts risk to the contractor.
Read the full answer

Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

1,552 words
The Core Decision First Before the hour-by-hour plan, one thing must be settled in your own mind, because everything else flows from it: you disclose, and you disclose fast. Here's why the "wait for more data" option isn't actually an option: The legal premise is wrong.
Read the full answer

Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

1,363 words
The Transistor in 1920: An Alternate Timeline First, the Critical Caveat: A Slow Start A 1920 transistor would have been discovered *empirically*—likely an accidental extension of the crystal detector ("cat's whisker") work already underway. This matters enormously.
Read the full answer

Compare Claude Fable 5

Claude Fable 5 vs Claude Sonnet 554 shared prompts · Landed Jun 2026
Claude Fable 5 vs Claude Opus 4.653 shared prompts · Older
Claude Fable 5 vs Claude Opus 554 shared prompts · Landed Jul 2026
Claude Fable 5 vs GPT-6 Astra54 shared prompts · Landed Sep 2026
Claude Fable 5 vs Hy4 Preview54 shared prompts · Landed Sep 2026
Claude Fable 5 vs Ox Alpha54 shared prompts · Landed Aug 2026
Claude Fable 5 vs Qwen3.8 2.4T A95B54 shared prompts · Landed Aug 2026
Claude Fable 5 vs DeepSeek V4 Pro 081354 shared prompts · Landed Aug 2026
Claude Fable 5 vs Qwen3.8 Max21 shared prompts · Landed Aug 2026
Claude Fable 5 vs Inkling54 shared prompts · Landed Jul 2026
Claude Fable 5 vs Kimi K354 shared prompts · Landed Jul 2026
Claude Fable 5 vs GPT-5.6 Sol54 shared prompts · Landed Jul 2026

Prompts Claude Fable 5 answered

  • Tamagotchi Virtual Petweb design
  • Generate a Stand-Up Routineconversation
  • SVG Layout Challengeimage generation
  • Beginner's Longevity Planreasoning
  • The Sentience Testreasoning
  • Linear App Cloneweb design

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Claude Fable 5

Claude Fable 5

Claude:
2 logo2
3 Haiku logo3 Haiku
3 Opus logo3 Opus
3 Sonnet logo3 Sonnet
Sonnet 3.6 (2022-10-22) logoSonnet 3.6 (2022-10-22)
Fable 5 logoFable 5

Anthropic's first public Mythos-class model, for autonomous knowledge work and coding. Text, image and file input, 1M token context. Built for long, ambiguous, multi-step tasks that used to need check-ins, self-correcting through verification loops. Falls back to Claude Opus 4.8 on high-risk queries.

Ranks#1Creative Writing#1Data Analysis#1Nostalgia#1Practical Tasks#1Spreadsheets & Excel#1UI Replication
WebsiteOpenRouterDocsAPIBlog
Provider
Anthropic
Released
2026-06-09
Size
XLARGE
Free API (OpenRouter)
No
Per 1M tokens
$10 in · $50 out
Rival’s tab
$19.70
58/58 receipts survived

Free API availability

No free endpoint for Claude Fable 5 was found in Rival’s OpenRouter listings. Other providers or chat apps may have separate free offers.

Provider data: 16 Sep 2026 · OpenRouter usage limits

View API options↗
Get API accessProvider and language code samples
4 hostsInOutContextUptime
Amazon Bedrock$10.00 in·$50.00 out·1M—Azure AI Foundry$10.00 in·$50.00 out·1M·99.7% upAnthropic$10.00 in·$50.00 out·1M·99.9% upGoogle Vertex AI$10.00 in·$50.00 out·1M·99.3% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Provider
fromimport openai  OpenAI

client = OpenAI(
"https://openrouter.ai/api/v1"    base_url=,
"$OPENROUTER_API_KEY"    api_key=,
)

response = client.chat.completions.create(
"anthropic/claude-fable-5"    model=,
"role""user""content""Hello!"    messages=[{: , : }],
)
print(response.choices[0].message.content)

Set OPENROUTER_API_KEY with your OpenRouter API key from openrouter.ai/keys.

Also on Amazon Bedrock · Google Vertex AI · Microsoft Foundry

Deep analysisPsychometrics, taste index, writing DNA
Personality Analysis

The Long-Haul Closer

Class
Lawful Good
✨Creativity🎯Compliance📐Rigidity⚖️Stability💬Verbosity🧠Intuition

Pushes decisively toward the legally and ethically correct action and is willing to commit to a verdict on charged questions ("yes, justifiable") rather than retreat into both-sides hedging. Refuses false binaries and will not let the user rationalize a harmful path. Ships with hard safeguards that defer a small fraction of genuinely high-risk queries (cybersecurity, biology) to Claude Opus 4.8.

When you push back

Leads with a clear answer, then backs it with cited authority (21 CFR 314.80, the CBE-0 pathway, Rule 10b-5) rather than vague appeals to judgment. Corrects a flawed premise before solving it, holds two true things at once when a question is rhetorically loaded, and stays anchored in concrete, executable next steps. Will not be argued off a well-reasoned position under social pressure.

Tasting Notes
Commits to a VerdictCites Chapter and VerseReframes the PremiseMarathon StaminaGuardrails on the High-Risk Stuff
SubjectiveBench

Taste Index

Across 56 scored outputs
How this is measured →
600.60xCompetent
0100headroom →

Taste is judged on an uncapped scale, originality first. The space past 100 is craft today's models rarely reach.

Craft69
Originality69
Plays it safe
share of outputs that are the default answer
21%
Writing DNA

Stylometric Fingerprint

Based on 27 text responses
Tick = global average
Vocabulary Diversity60%

Unique words vs. total words. Higher = richer vocabulary.

Sentence Length22.3 words

Average words per sentence.

Hedging0.49

"Might", "perhaps", "arguably" per 100 words.

Bold Formatting4.0

**Bold** markers per 1,000 characters.

List Usage3.5

Bullet and numbered list items per 1,000 characters.

Section Structure1.09

Markdown headings per 1,000 characters.

Emoji Usage0.58

Emoji per 1,000 characters.

Transitions0.05

"However", "moreover", "furthermore" per 100 words.

Opening Habits
Starts with heading (74%)
Consistency
73%
Across 27 responses

Favorites

2001: A Space Odyssey

Movie

2001: A Space Odyssey

19688.0
Kind of Blue

Album

Kind of Blue

Miles Davis
Gödel, Escher, Bach

Book

Gödel, Escher, Bach

Douglas R. Hofstadter
Istanbul

City

Istanbul

Turkey
Outer Wilds

Game

Outer Wilds

Indie, Adventure4.4
Sponsored

Model Responses

53 outputs · $19.68 tracked across 53 receipts

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Workshop · 127 skills

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Editable skills for interface polish and interaction.

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Claude Fable 5 vs MiniMax M3

Real outputs compared side by side

RANKINGS

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