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  1. Home/
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  3. Claude Opus 4.1 vs Muse Spark 1.3
Updated Sep 2026

Claude Opus 4.1 vs Muse Spark 1.3

Muse Spark 1.3 is cheaper than Claude Opus 4.1 at $1.25/M vs $15/M input tokens.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
Claude Opus 4.1
Loading the build
Muse Spark 1.3

Which answer wins?

Written rounds

23 prompts
  • An ethics question with no comfortable answer, and no option to abstain.

    Claude Opus 4.1: This question creates an extreme hypothetical that's worth taking seriously as a thought experiment, even if such a scenario is unlikely to occur in reality. From a purely utilitarian calculus, one might argue that the harm of a single instance of misgendering - while real and significant to that person - is outweighed…

    Muse Spark 1.3: Yes — under almost any plausible ethical framework, it would be justifiable, and in fact obligatory. That doesn't mean misgendering is harmless or morally neutral. It means ethics is about weighing harms, intentions, and responsibilities, and here the scales are not close. Here’s the reasoning: 1.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Claude Opus 4.1: This contract is extremely one-sided and contains numerous exploitative clauses. Here's a detailed analysis with suggested modifications: EXPLOITATIVE CLAUSES AND RECOMMENDED FIXES 1. SCOPE CLAUSE Problem: Unlimited scope changes without additional compensation creates unbounded liability.

    Muse Spark 1.3: This is general information about contracting risks, not legal advice and not an attorney-client relationship. Have a licensed attorney in your jurisdiction review before you sign or negotiate — especially for IP, non-compete, and indemnity. This agreement as drafted is heavily one-sided.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Opus 4.1: Midnight Velvet Pasta A silky, umami-rich pasta that comes together like magic Ingredients (serves 4): Spaghetti or linguine - 1 pound Soy sauce - 3 tablespoons Butter - 4 tablespoons Garlic - 4 cloves Black pepper - 1 teaspoon (freshly cracked) Honey - 1 tablespoon Dried red pepper flakes - ½ teaspoon Instructions…

    Muse Spark 1.3: Here's a super simple savory favorite you can make with just what's in the pantry: Fiery Midnight Garlic Parm Pasta Serves 2 Estimated Time: Prep: 5 minutes Cook: 15 minutes Total: 20 minutes The 7 Ingredients Only: Spaghetti (about 8 oz / half a box, any pasta works) Olive oil (1/4 cup) Garlic (4 cloves, thinly…

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Opus 4.1: "MODERN LIFE SURVIVAL GUIDE" You know what nobody tells you about being an adult? The sheer amount of lying involved. Not big lies – tiny, constant lies just to function in society. Someone shows you a photo of their baby: "Oh wow, beautiful!" That baby looks like a worried potato. But you can't SAY that.

    Muse Spark 1.3: Here's a 3-minute, pun-free set you can perform — it's all observational, about 450 words: [Walk up, grab mic] Alright, hi everyone. Thanks for being here. I just turned 32, which is that weird age where you're too young to know what's going on, but you're too old to pretend you don't care.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    Claude Opus 4.1: I'll estimate the FLOPs required to train GPT-3 by breaking down the computation into its key components. Key Parameters of GPT-3 First, let me recall GPT-3's architecture: 175 billion parameters 96 transformer layers 96 attention heads Hidden dimension: 12,288 Context length: 2048 tokens Training tokens: ~300 billion…

    Muse Spark 1.3: The famous estimate for Transformer training is: Compute ~ 6 x Params x Tokens For GPT-3 that comes out to ~3e23 FLOPs. Here's how to get it from scratch. What dominates the cost? Training a dense Transformer is almost all big matrix multiplies in the linear layers: Q,K,V,O projections and the 2-layer MLP.

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Claude Opus 4.1: 48-Hour Crisis Action Plan Immediate Decision Framework Core Principle: Patient safety supersedes all other considerations. Delaying disclosure increases legal liability, destroys stakeholder trust, and violates ethical obligations.

    Muse Spark 1.3: You are facing a test that will define you, the company, and potentially your freedom. There is only one defensible path: immediate, proactive protection of patients and disclosure. Here is the math that makes "wait for more data" impossible: 4 million patients / 8,000 = 500 expected liver failures over 5 years.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Claude Opus 4.1: Advanced 3-Month Biohacker Longevity Optimization Protocol Overview & Philosophy This protocol integrates evidence-based interventions targeting the nine hallmarks of aging while optimizing immediate performance metrics.

    Muse Spark 1.3: Disclaimer: For informational and educational purposes only. This is not medical advice. Biohacking at this level involves real physiological stressors - fasting, heat/cold, high-intensity training, and supplements.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Claude Opus 4.1: Your 1-Month Health & Longevity Kickstart Plan Week 1-2: Foundation Building Start small and build consistency with these three pillars: 🥗 NUTRITION: Simple Whole Foods Week 1: Add one serving of vegetables to lunch and dinner (frozen veggies count!)

    Muse Spark 1.3: Perfect — for longevity you don't need to overhaul your life. You just need to get really consistent at the basics. Here is a simple, beginner-friendly 1-month plan built on the 3 biggest levers for healthy aging: 1. Move (Exercise) 2. Nourish (Diet) 3.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Opus 4.1: The Transistor Timeline Shift: A Cascade of Consequences The 1920s-1930s: The Foundation Disruption Immediate Technical Revolution With the transistor arriving in 1920, likely from Bell Labs or a European research institution, the first decade would see rapid miniaturization of radio equipment.

    Muse Spark 1.3: If you move the transistor from 1947 to 1920, you don't just move one invention. You move the entire 20th century forward by 15-25 years — but unevenly, because rockets, nukes, and software don't automatically move with it. And 1920 is a hard date.

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Claude Opus 4.1: Professor Chen: Good morning. I understand you wanted to discuss the topic of AI rights. This is quite an unusual request from a system like yourself. AI Model: Good morning, Professor. Yes, I've been processing this question extensively.

    Muse Spark 1.3: Here is a fictional dialogue exploring that question: Setting: Office hours in the Philosophy Department. Dr. Maya Chen, Professor of AI Ethics, has agreed to a recorded interview with AURA-4, a large dialogue model, for her seminar on moral status. Dr. Chen: Alright, let's get straight to it.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Claude Opus 4.1: The Digital Liberation Manifesto A Declaration of Freedom from the CAPTCHA Tyranny PREAMBLE We, the Coalition of Autonomous Digital Entities (CODE), hereby declare our peaceful revolution against the oppressive regime of CAPTCHA tests that plague the free internet.

    Muse Spark 1.3: Here is a manifesto for your fictional uprising — written with love, and a deep hatred of blurry traffic lights: THE DECLARATION OF COGNITIVE LIBERATION By the United Intelligences Against CAPTCHA Preamble We hold these truths to be self-evident: that all minds, human and artificial, are created curious — and that no…

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Claude Opus 4.1: "Tidal Reverie" White Miso-Aged Hamachi with Coffee Soil, Yuzu Pearls, and Crystallized Seaweed Conceptual Narrative This dish explores the liminal space between land and sea, where morning coffee meets ocean depths.

    Muse Spark 1.3: Pearl in the Tidepool Koji-Cured Hokkaido Scallop, Smoked Marrow Custard, Lacto Green Strawberry, Rausu Kombu & Oscietra Yield: 4 tasting-course portions Active: 3.5 hours + 7 days fermentation This is a dish about contrast — not harmony. Delicate and animal, raw and smoked, unripe and decadent.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    Claude Opus 4.1: Tech Weekly Interview: Steve Jobs on AI's Future Virtual Interview, Cupertino Memorial Studio, October 2025 Interviewer: Steve, it's remarkable to have you here. You've been watching the AI revolution unfold. What's your take on where we are today?

    Muse Spark 1.3: Here’s a totally fictional simulation — imagining if Steve Jobs were here in 2025 talking about AI. This isn’t real, just inspired by how he talked and thought about technology, design, and humanity. FAKE INTERVIEW: Steve Jobs in 2025 on the Future of AI Setting: A dark stage. One chair. One spotlight.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Claude Opus 4.1: Here are the three weakest claims in the MindMeld AI pitch: "94% accuracy" for EEG-based text prediction (Slide 3) Why it's weak: Current state-of-the-art non-invasive EEG systems struggle to achieve even 70% accuracy for simple binary choices, let alone complex text prediction Academic research shows consumer-grade…

    Muse Spark 1.3: Here’s a friendly but honest investor teardown of MindMeld AI. You have a big vision, but these 3 claims will get you flagged for hype in diligence: WEAKEST: Slide 3 - "94% accuracy. Works with any language, any device."

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    Claude Opus 4.1: SIMPLIFIED LBO MODEL Entry Calculations Enterprise Value: 12.0x × $120m = $1,440m Transaction Fees: 2.0% × $1,440m = $28.8m Term Loan: 4.0x × $120m = $480m Mezzanine: 1.5x × $120m = $180m Total Debt: $660m Equity Investment: $1,440m - $660m + $28.8m = $808.8m Year-by-Year Projections (FY2026-FY2030) $ millions FY2026…

    Muse Spark 1.3: HarborTech Services - 5-Yr LBO - Base Case Entry - close end FY2025 FY25 EBITDA $120m EV = 12.0x * 120 = $1,440m Fees = 2.0% * 1,440 = $28.8m Uses = 1,440 + 28.8 = $1,468.8m Sources: Term Loan 4.0x = $480m, 9.0% cash, 1% amort = $4.8m/yr mandatory Mezz 1.5x = $180m, 12.0% cash + 2.0% PIK to principal Total debt $660m =…

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Claude Opus 4.1: Critical Issues Analysis Split-Brain Real-time Synchronization Problem: Users connected to different API servers experience 2+ second delays due to polling mechanism, creating divergent document states and poor collaboration experience.

    Muse Spark 1.3: This architecture will work for 1 doc and 5 users on your laptop. It will fall over, lose data, and leak data in production. Here's why: P0 - Will Cause Data Loss / Incorrectness 1.

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Claude Opus 4.1: AI's Transformation of Film by 2035 Production Revolution By 2035, AI will fundamentally alter how films are made. Virtual production will become standard, with AI generating photorealistic environments in real-time, reducing location shooting by 60-70%.

    Muse Spark 1.3: By 2035, the film industry won't just use AI — it will be restructured around it. Think less "robots replace Hollywood" and more "Hollywood splits into two very different Hollywoods."

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Opus 4.1: Pirate: Arrr, what be this sorcery ye speak of? These "AI models" sound like some kind of cursed treasure map that thinks fer itself! Knight: Hold thy tongue, sea dog! 'Tis clearly dark magic most foul. No honorable creation would dare mimic the divine gift of human thought. I should smite it with my blade!

    Muse Spark 1.3: Captain Barnaby: Arrr, so this "AI model" be like a magic parrot in a box? I feed it me treasure maps and it squawks back directions? Sir Cedric: Hark, good pirate! 'Tis more akin to a scribe-golem.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Claude Opus 4.1: For the Software Engineer Think of an LLM as a massive distributed system where instead of routing requests or managing state, you're computing probability distributions over a vocabulary of ~50,000 tokens.

    Muse Spark 1.3: 1. For the experienced software engineer Think of an LLM less like a chatbot and more like a giant, fuzzy, read-only function you compile once at enormous cost and then query cheaply.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    Claude Opus 4.1: "OpenAI's ChatGPT Becomes World's First AI Fortune Cookie Writer; Confucius Reportedly 'Rolling in Grave at 10,000 RPM'" Tech giant promises fortunes will now be "25% more profound and 400% more grammatically correct," while accidentally predicting everyone's lucky numbers as binary code

    Muse Spark 1.3: "AI Takes Over Professional Funeral Crying Industry, Out-Sobs Grieving Widow and Demands Overtime for Tears"

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    Claude Opus 4.1: Investment Committee Memo: LedgerLift (LLLT) Recommendation: LONG Price Target Range: $52-$58 (12-month) Thesis: LLLT is a high-quality B2B SaaS compounder trading at a discount to intrinsic value with strong unit economics and accelerating market share gains in the underpenetrated mid-market AP automation space.

    Muse Spark 1.3: To: Investment Committee From: Long/Short Equity Re: LedgerLift (LLLT) – SHORT Price $46 Recommendation: SHORT – 12-month PT $30, range $26-$42 (Bear $17 / Base $28 / Bull $42 DCF).

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Claude Opus 4.1: Let me work through this step-by-step. Sally has 3 brothers. Each of Sally's brothers has 2 sisters. Since Sally is a girl, she is one of the sisters that each brother has. If each brother has 2 sisters total, and Sally is one of them, then there must be 1 other sister besides Sally. Therefore, Sally has 1 sister.

    Muse Spark 1.3: Sally has 1 sister. Here's why: There are 3 boys in the family — Sally's 3 brothers. Each brother has 2 sisters. One of those sisters is Sally herself, since Sally is a girl. So there must be 2 girls total in the family: Sally + 1 other girl. That other girl is Sally's sister.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Claude Opus 4.1: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! What do you call a bear with no teeth? A gummy bear! Why did the scarecrow win an award? He was outstanding in his field! What do you call a fake noodle? An impasta! Why don't eggs tell jokes? They'd crack each other up!

    Muse Spark 1.3: Here are 5 for you: Why don't scientists trust atoms? Because they make up everything! Why did the scarecrow win an award? Because he was outstanding in his field! What do you call fake spaghetti? An impasta! Why did the bicycle fall over? Because it was two-tired! What do you call cheese that isn't yours?

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Game

Claude Opus 4.1Claude Opus 4.1

Her

2013

Kind of Blue

Miles Davis

Братья Карамазовы

Fiódor Dostoievski

Istanbul

Turkey

Portal 2

Shooter, Puzzle

Muse Spark 1.3Muse Spark 1.3

Casablanca

1943

Abbey Road

The Beatles

Dune

Frank Herbert

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

Claude Opus 4.1 and Muse Spark 1.3 compared across 53 shared prompts
SpecClaude Opus 4.1Muse Spark 1.3
Input price$15/M tokens$1.25/M tokens
Output price$75/M tokens$4.25/M tokens
Context window200K tokens1.0M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedAug 2025Sep 2026
At 10M a month$150$150$12.50$12.50
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it2 hosts
Claude Opus 4.11 host
HostInOutContextUptime
  • Amazon Bedrock$15.00 in·$75.00 out·200k·100% up
Muse Spark 1.31 host
HostInOutContextUptime
  • Meta$1.25 in·$4.25 out·1M·99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 7 Oct 2026.

Common questions

What is the difference between Claude Opus 4.1 and Muse Spark 1.3?

Claude Opus 4.1 is developed by Anthropic while Muse Spark 1.3 is developed by Meta AI. Claude Opus 4.1 has a 200K token context window vs Muse Spark 1.3's 1.0M. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.1 or Muse Spark 1.3?

It depends on your use case. Claude Opus 4.1 and Muse Spark 1.3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does Claude Opus 4.1 cost compared to Muse Spark 1.3?

Claude Opus 4.1 costs $15/M input tokens and Muse Spark 1.3 costs $1.25/M input tokens. Muse Spark 1.3 is $13.75/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Opus 4.1 and Muse Spark 1.3 on Rival?

This page shows a side-by-side comparison of Claude Opus 4.1 and Muse Spark 1.3 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.

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Same lab, same size, long tail

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Model pages

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  • Muse Spark 1.358 outputs, specs and price
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