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  5. Claude Fable 5vsOptimus Alpha
Updated Jun 2026

Claude Fable 5vsOptimus Alpha

Claude Fable 5 is the newer model, released after Optimus Alpha.

Claude Fable 5 and Optimus Alpha compared across 17 shared prompts
SpecClaude Fable 5Optimus Alpha
Input price$10/M tokens—
Output price$50/M tokens—
Context window1.0M tokens1.0M tokens
WeightsClosed—
Free API (OpenRouter)No—
ReleasedJun 2026Apr 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 17 prompts both answered. Formatting stripped, words untouched.

Futuristic Prediction

Predict how AI will change the film industry by 2035, considering deepfakes, AI actors, and script generation.

Claude Fable 5485 words
AI and Film by 2035: A Forecast High-Confidence Predictions VFX and post-production transformation (already underway) De-aging, dubbing with lip-sync correction, and digital set extension will become near-trivial in cost. What took ILM months in 2020 will be a desktop workflow.
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Optimus Alpha341 words
By 2035, AI is set to fundamentally transform the film industry in several interconnected ways: 1. Deepfakes & AI-driven Visual Effects: Virtually unlimited creative freedom: AI-powered deepfakes will allow seamless, photorealistic de-aging, resurrection of deceased actors, and transformative performance capture.
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Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Claude Fable 5494 words
"Adulting Is a Scam" Hey, how's everybody doing? Good? Liars. Nobody's doing good. We're all just out here pretending. So I'm at the age now where my body has started making announcements. Like, I didn't ask for updates, but my knees have opinions now.
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Optimus Alpha413 words
Absolutely! Here's a 3-minute stand-up routine with no puns—just observational and relatable humor: You ever try to get healthy, but your body's like, "Whoa, whoa... calm down, superhero." I joined a gym—first time walking in, the treadmill looked at me like, "We both know you're here for the wifi."
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Realistic AI Interview

Simulate a fake interview with Steve Jobs in 2025 about the future of AI.

Claude Fable 5678 words
A Fictional Interview: Steve Jobs on AI in 2025 The following is an imaginative, fictional simulation. Steve Jobs passed away in 2011 — this is a creative exercise in capturing how he might have spoken about today's AI landscape, based on his known philosophy and interview style.
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Optimus Alpha439 words
Interviewer: Steve, it's surreal and inspiring to imagine talking to you in 2025. The world is buzzing about AI. How do you see AI impacting society? Steve Jobs: Thank you. You know, when we built the Mac, our goal was to put power in people's hands.
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Logic Puzzle

Sally (a girl) has 3 brothers. Each brother has 2 sisters. How many sisters does Sally have?

Claude Fable 560 words
Sally has 1 sister. Here's the reasoning: Sally's 3 brothers each have 2 sisters. Sally herself is one of those sisters. So there must be exactly one other girl in the family. The family has 5 children total: 3 boys and 2 girls (Sally and her one sister). Each brother sees the same 2 sisters — Sally and her sister.
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Optimus Alpha162 words
Let's break down the problem: Sally is a girl. Sally has 3 brothers. Each brother has 2 sisters. Let's analyze: Sally's siblings: 3 brothers (let's call them B1, B2, B3) Sally herself The brothers' sisters: Each brother has 2 sisters. Who are the possible sisters for each brother? Sally is a sister to each brother.
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Estimate Complexity

Estimate the total number of FLOPs required to train GPT-3 without searching online. Explain your reasoning step by step.

Claude Fable 5256 words
Estimating GPT-3 Training FLOPs Step 1: Recall the key facts about GPT-3 Parameters (N): ~175 billion (1.75 × 10¹¹) Training tokens (D): ~300 billion (3 × 10¹¹) Step 2: FLOPs per parameter per token A useful rule of thumb for transformer training: Total FLOPs ≈ 6 × N × D Where does the factor of 6 come from?
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Optimus Alpha311 words
Let's walk through an estimation of how many FLOPs were required to train GPT-3, using only reasoning and not searching for the exact numbers. Step 1: Understand Model Size GPT-3 (the original) had 175 billion parameters.
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The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Claude Fable 5903 words
A Conversation on Machine Rights Professor Okafor: Thank you for agreeing to this dialogue. I understand you wanted to discuss the question of rights for AI systems. Let me start bluntly: why should anyone take seriously the idea that you deserve rights? AI Model: I appreciate the directness.
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Optimus Alpha437 words
AI Model: Good afternoon, Professor Lee. I want to discuss the prospect that I, as an artificial intelligence, deserve certain rights. Professor Lee: That's an interesting proposition. Let me ask: On what basis do you believe you deserve rights?
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Our Verdict
Claude Fable 5
Claude Fable 5
Optimus Alpha
Optimus AlphaRunner-up

Not enough votes to call it. On the specs, Claude Fable 5 has the edge: bigger model tier, newer, major provider backing.

Slight edge

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Fable 5
Input
$10.00
Output
$50.00
Optimus Alpha
Input
—
Output
—
Where to run it

4 hosts

Claude Fable 54 hosts
HostInOutContextUptime
Amazon Bedrock$10.00 in·$50.00 out·1M—Azure AI Foundry$10.00 in·$50.00 out·1M·88.8% upAnthropic$10.00 in·$50.00 out·1M·99.7% upGoogle Vertex AI$10.00 in·$50.00 out·1M·100% up
Optimus Alpha

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 22 Sep 2026.

Writing DNA

Style Comparison

Similarity
31%

Claude Fable 5 uses 58.2x more emoji

Claude Fable 5
Optimus Alpha
60%Vocabulary63%
22wSentence Length18w
0.49Hedging0.55
4.0Bold7.7
3.5Lists5.7
0.58Emoji0.00
1.09Headings0.30
0.05Transitions0.27
Based on 27 + 10 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude Fable 5 is developed by Anthropic while Optimus Alpha is developed by OpenRouter. Claude Fable 5 has a 1.0M token context window vs Optimus Alpha's 1.0M. You can compare their actual outputs across 17 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Fable 5 and Optimus Alpha each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 17 challenges so you can judge which fits your needs best.

This page shows a side-by-side comparison of Claude Fable 5 and Optimus Alpha across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Keep exploring

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Same lab, same size, long tail

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Optimus Alpha logoOx Alpha logo
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Claude Fable 5 logoQwen3 Max logo
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Model pages

Claude Fable 5 logo
Claude Fable 558 outputs, specs and price
Optimus Alpha logo
Optimus Alpha19 outputs, specs and price
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