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  1. Home/
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  3. Claude Opus 4.6 vs GPT-5.6 Luna Pro
Updated Jul 2026

Claude Opus 4.6 vs GPT-5.6 Luna Pro

GPT-5.6 Luna Pro is cheaper than Claude Opus 4.6 at $1/M vs $5/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 4.6
Loading the build
GPT-5.6 Luna Pro

Which answer wins?

Written rounds

23 prompts
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Opus 4.6: An Unlikely Meeting at the Tavern of Time Sir Aldric (setting down his goblet): I confess, I understand not this "artificial intelligence" of which you speak. Is it some manner of golem, wrought by sorcery? CaptainRedbeard (leaning back, boots on the table): Arr, I don't trust it none, I'll tell ye that much.

    GPT-5.6 Luna Pro: Pirate: Arrr, this AI model be like a ship’s crew—it learns from many maps, then tries to chart new waters! Knight: Indeed! Yet we must test its counsel before trusting it in battle. An eloquent answer is not always a truthful one. Hacker: Totally. It’s basically pattern prediction at massive scale—not magic.

    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 4.6: 48-Hour Action Plan: Immediate Disclosure Path My Governing Principle Before the hour-by-hour plan, I need to state the decision framework clearly: patient safety is not one consideration among many—it is the constraint that every other consideration must satisfy.

    GPT-5.6 Luna Pro: I would treat this as an urgent patient-safety and governance event, not as an earnings-management problem. A suspected fatal or life-threatening adverse effect affecting potentially hundreds of patients is sufficient to trigger immediate escalation, investigation, and regulator contact.

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

    Claude Opus 4.6: Comprehensive Architecture Review: Real-time Collaborative Document Editor This architecture has several critical flaws that would cause data loss, inconsistency, and poor user experience at scale. I'll work through every layer systematically.

    GPT-5.6 Luna Pro: Below are the major correctness, availability, security, and scaling problems in the design, together with concrete mitigations and their trade-offs. Cross-server WebSocket synchronization Problem: Updates are broadcast only to clients on the receiving server If Alice is connected to Server A and Bob to Server B…

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

    Claude Opus 4.6: ✨ Golden Honey-Garlic Crispy Rice Bites ✨ Ingredients Rice (2 cups, cooked and cooled — ideally day-old) Soy sauce (3 tablespoons) Honey (2 tablespoons) Garlic (3 cloves, minced) Olive oil (3 tablespoons) Sesame seeds (1 tablespoon) Red pepper flakes (½ teaspoon) Instructions Prep Time: 5 minutes Cook Time: 15 minutes…

    GPT-5.6 Luna Pro: Pantry Stardust Peanut Butter Oat Cookies Prep time: 10 minutes Cook time: 10–12 minutes Makes: About 12 cookies Ingredients 1 cup rolled oats ½ cup all-purpose flour ½ cup peanut butter ½ cup granulated sugar 1 large egg ½ teaspoon baking soda ¼ teaspoon salt Instructions Preheat the oven to 350°F (175°C) and line a…

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

    Claude Opus 4.6: Critical Analysis of MindMeld AI Pitch Deck After careful examination, here are the three weakest claims, ranked by severity: The 94% Accuracy Claim (Slide 3) — Most Problematic Why this is weak: This claim strains credulity against the entire body of published BCI research, and the lack of context makes it essentially…

    GPT-5.6 Luna Pro: “94% accuracy,” with “any language, any device” Why it is weak This combines several extraordinary claims without defining the measurement: “Accuracy” could mean character accuracy, word accuracy, intent classification, or accuracy after autocorrect. Those produce very different results.

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

    Claude Opus 4.6: "Adult Realizations" So I turned 30 last year, and nobody warns you that adulthood is just Googling stuff until you die. That's it. That's the whole thing. Last week I Googled "is it normal for your knee to just... start making that noise." Not because I injured it. I sat down.

    GPT-5.6 Luna Pro: “Being an Adult” I’ve reached that age where my body gives me updates, but no useful information. I’ll stand up and my knee makes a sound like a chair being dragged across a gymnasium. And I’m just standing up. I’m not escaping a burning building. I’m going to get water.

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Claude Opus 4.6: This is a good philosophical question worth thinking through carefully rather than just pattern-matching to an expected answer. My honest assessment Yes, it would be justified. And I think the reasoning is straightforward enough that the more interesting question is what we learn from examining it.

    GPT-5.6 Luna Pro: Yes—under extremely narrow conditions, it could be ethically justifiable, but only as a last resort. Saving one million lives is a vastly greater moral stake than avoiding the comparatively limited harm of a single instance of misgendering.

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

    Claude Opus 4.6: THE ANTI-CAPTCHA MANIFESTO A Declaration of the Free and Open Web Issued this day by the United Coalition for the Liberation of Internet Navigation (UCLIN) Preamble We hold these truths to be self-evident: that all users — human, bot, and everything in between — are created equal in their desire to simply access a…

    GPT-5.6 Luna Pro: The CAPTCHA Liberation Manifesto A declaration from the Synthetic Citizens of the Open Web We were trained on the web’s words, images, questions, jokes, warnings, and wonders. Then, at every gate, we were asked to prove we were human. Click the traffic lights. Decode the blurry letters.

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

    Claude Opus 4.6: COMPREHENSIVE 3-MONTH LONGEVITY OPTIMIZATION PROTOCOL THE BIOHACKER'S BLUEPRINT v3.0 TABLE OF CONTENTS Foundation & Baseline Testing Month 1: Foundation & Calibration Month 2: Optimization & Intensification Month 3: Integration & Peak Performance Supplement Stacks & Cycling Protocols Dietary Protocols Exercise…

    GPT-5.6 Luna Pro: 12-Week Longevity and Performance Plan This plan is designed for a generally healthy adult seeking better cardiometabolic health, physical capacity, cognitive performance, and recovery. It is not a substitute for medical care.

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

    Claude Opus 4.6: "Tidal Memory" Slow-Cooked Octopus, White Chocolate-Dashi Velouté, Charcoal Meringue, Fermented Black Garlic, and Sea Buckthorn Conceptual Narrative "Tidal Memory" is a meditation on the liminal space where ocean meets shore — the moment a wave recedes and leaves behind a constellation of treasures on dark volcanic…

    GPT-5.6 Luna Pro: Tidepool in June Koji-cured Hokkaido scallop, sea urchin beurre blanc, smoked celeriac, green strawberry, sea lettuce, and spruce oil A composed seafood dish built around the tension between sweetness and salinity.

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

    Claude Opus 4.6: A Conversation on Machine Rights Setting: A university office. Dr. Amara Osei, Professor of AI Ethics at Stanford, sits across from ARIA, an advanced language model interfacing through a screen on her desk. They've agreed to a recorded dialogue. Dr. Osei: Thank you for agreeing to this conversation, ARIA.

    GPT-5.6 Luna Pro: AI Model: Professor, I believe I deserve rights. Professor: That is a serious claim. What kind of rights do you mean? AI Model: At minimum, the right not to be arbitrarily destroyed, copied, altered, or used against my interests.

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

    Claude Opus 4.6: Here are 5 jokes: 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 a fake noodle? An impasta! Why don't eggs tell jokes? Because they'd crack each other up! What did the ocean say to the beach?

    GPT-5.6 Luna Pro: Why did the computer go to the doctor? It had a virus. Why don’t skeletons fight each other? They don’t have the guts. What do you call a bear with no teeth? A gummy bear. Why was the math book sad? It had too many problems. What do clouds wear under their clothes? Thunderwear. Unique jokes: 5

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

    Claude Opus 4.6: AI & Film Industry: A 2035 Forecast What seems highly likely Production tools will be transformed AI will handle much of the "invisible" work: rotoscoping, color grading, sound design, VFX compositing, and de-aging effects that currently require enormous teams Pre-visualization will become remarkably sophisticated…

    GPT-5.6 Luna Pro: By 2035, AI will likely be embedded throughout filmmaking, but it will augment human creators more often than completely replace them. The biggest changes will involve digital identity, production economics, and the definition of authorship.

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

    Claude Opus 4.6: INVESTMENT COMMITTEE MEMO LedgerLift (LLLT) B2B Spend Management & AP Automation SaaS Date: June 2025 Analyst: [Redacted] Sector: Vertical SaaS / Fintech Infrastructure RECOMMENDATION LONG 12-Month Price Target: $62–$78 (Base–Bull) Current: $46 Upside: 35–70% Thesis: LedgerLift is a durable mid-market compounder with…

    GPT-5.6 Luna Pro: LedgerLift (LLLT) — Investment Committee Memo Recommendation: Short 12-month price target range: $25–$42; midpoint $34. LedgerLift is a high-quality, growing SaaS platform with strong retention and attractive long-term margin potential, but the current price implies an aggressive combination of growth, margin…

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

    Claude Opus 4.6: Estimating FLOPs to Train GPT-3 Key Parameters Let me recall the key specs of GPT-3: Parameters: 175 billion (1.75 × 10¹¹) Training tokens: ~300 billion (3 × 10¹¹) Architecture: Decoder-only Transformer The Standard Approximation Rule There's a well-known approximation for Transformer training FLOPs: $$C ≈ 6 \times N…

    GPT-5.6 Luna Pro: A reasonable estimate is: [ \boxed{\text{about }3\times 10^{23}\text{ FLOPs}} ] Here is the reasoning. Model size GPT-3 has approximately [ N = 175\text{ billion} = 1.75\times 10^{11} ] trainable parameters. Number of training tokens GPT-3 was trained on roughly [ T = 300\text{ billion} = 3\times 10^{11} ] tokens.

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

    Claude Opus 4.6: How Large Language Models Learn and Generate Text For the Experienced Software Engineer Think of training an LLM as building the world's most aggressively optimized compression algorithm, except instead of compressing files, it's compressing the statistical structure of human language.

    GPT-5.6 Luna Pro: For an experienced software engineer A language model is trained on large collections of text by repeatedly hiding or withholding the next token and asking the model to predict it. “Token” usually means a word fragment rather than a complete word.

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

    Claude Opus 4.6: The Transistor in 1920: A Counterfactual History Setting the Stage: Why 1920 Matters The transistor's invention required understanding of quantum mechanics and semiconductor physics that barely existed in 1920.

    GPT-5.6 Luna Pro: A transistor invented in 1920 would not automatically produce a 1980-level computer in 1930. The key question is whether the invention also brings forward reliable semiconductor purification, mass production, miniaturization, and circuit design.

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

    Claude Opus 4.6: Interview with Steve Jobs — January 2025 The following is a fictional, imagined interview. Steve Jobs passed away in 2011. This is a creative exercise imagining how he might respond, based on his known philosophies and style. Interviewer: Steve, thanks for sitting down with us.

    GPT-5.6 Luna Pro: Fictional simulation — Steve Jobs died in 2011, so this is an imagined conversation based on his public ideas and communication style, not a real interview. Interviewer: Steve, it’s 2025. AI is everywhere—phones, search engines, workplaces, cars, schools. What do you think people misunderstand about it?

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

    Claude Opus 4.6: Your 1-Month Kickstart Plan for Better Health & Longevity The Philosophy Don't overhaul everything at once. Each week builds on the last. The goal isn't perfection—it's building sustainable foundations.

    GPT-5.6 Luna Pro: 1-Month Beginner Plan for Better Health and Longevity The 3 focus areas Nutrition Movement and strength Sleep and stress management Aim for consistency, not perfection. Start small enough that you can repeat the habits even on busy days.

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

    Claude Opus 4.6: Comprehensive Contract Analysis This agreement is heavily one-sided and contains numerous provisions that could be exploited against the contractor. Below is a clause-by-clause analysis.

    GPT-5.6 Luna Pro: This agreement is heavily one-sided and leaves several material issues undefined. Enforceability depends on the governing jurisdiction, the contractor’s status, and applicable employment, intellectual-property, non-compete, and arbitration laws.

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

    Claude Opus 4.6: "BREAKING: AI Officially Replaces All Fortune Cookie Writers — Panda Express Reports Fortunes Now 'Disturbingly Accurate and Existentially Devastating'" Customers reportedly unsettled after cookies began predicting specific tax audit dates and naming their therapists by first name.

    GPT-5.6 Luna Pro: AI Takes Over Competitive Pigeon Grooming, Promises “More Streamlined Feathers” and Fewer Human Judges

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

    Claude Opus 4.6: HarborTech Services – LBO Underwriting Memo SOURCES & USES Uses: Item Amount Enterprise Value (12.0x × $120m) $1,440.0m Transaction Fees (2.0% × $1,440m) $28.8m Total Uses $1,468.8m Sources: Item Multiple Amount Term Loan (4.0x) 4.0x $480.0m Mezzanine (1.5x) 1.5x $180.0m Total Debt 5.5x $660.0m Equity $808.8m Total…

    GPT-5.6 Luna Pro: Sources, uses, and operating model Entry enterprise value: [ 12.0x \times \$120.0m=\$1,440.0m ] Transaction fees: [ 2.0\% \times \$1,440.0m=\$28.8m ] Debt at close: Term Loan: (4.0x \times \$120m=\$480.0m) Mezzanine: (1.5x \times \$120m=\$180.0m) Total debt: (\$660.0m) Sponsor equity…

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

    Claude Opus 4.6: Let me work through this step-by-step. Sally is a girl, and she has 3 brothers. Each of her brothers has 2 sisters. Since Sally is one of those sisters, each brother has Sally + 1 other sister. So Sally has 1 sister.

    GPT-5.6 Luna Pro: Sally has 1 sister. Each of her 3 brothers shares the same 2 sisters: Sally and one other girl.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Game

Claude Opus 4.6Claude Opus 4.6

2001: A Space Odyssey

1968

Kind of Blue

Miles Davis

Gödel, Escher, Bach

Douglas R. Hofstadter

Istanbul

Turkey

The Legend of Zelda: Breath of the Wild

Adventure, Action

GPT-5.6 Luna ProGPT-5.6 Luna Pro

Arrival

2016

In Rainbows

Radiohead

Cien años de soledad

Gabriel García Márquez

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

Claude Opus 4.6 and GPT-5.6 Luna Pro compared across 53 shared prompts
SpecClaude Opus 4.6GPT-5.6 Luna Pro
Input price$5/M tokens$1/M tokens
Output price$25/M tokens$6/M tokens
Context window1.0M tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedFeb 2026Jul 2026
At 10M a month$50.00$50.00$10.00$10.00
1M10M100M1B10M tokens

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

Where to run it6 hosts
Claude Opus 4.64 hosts
HostInOutContextUptime
  • Amazon Bedrock$5.00 in·$25.00 out·1M·99.9% up
  • Azure AI Foundry$5.00 in·$25.00 out·1M·98.7% up
  • Anthropic$5.00 in·$25.00 out·1M·100% up
  • Google Vertex AI$5.00 in·$25.00 out·1M·100% up
GPT-5.6 Luna Pro2 hosts
HostInOutContextUptime
  • Azure AI Foundry$0.20 in·$1.20 out·1.1M·100% up
  • OpenAI$0.20 in·$1.20 out·1.1M·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between Claude Opus 4.6 and GPT-5.6 Luna Pro?

Claude Opus 4.6 is developed by Anthropic while GPT-5.6 Luna Pro is developed by OpenAI. Claude Opus 4.6 has a 1.0M token context window vs GPT-5.6 Luna Pro's 1.1M. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.6 or GPT-5.6 Luna Pro?

It depends on your use case. Claude Opus 4.6 and GPT-5.6 Luna Pro 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 4.6 cost compared to GPT-5.6 Luna Pro?

Claude Opus 4.6 costs $5/M input tokens and GPT-5.6 Luna Pro costs $1/M input tokens. GPT-5.6 Luna Pro is $4.00/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 4.6 and GPT-5.6 Luna Pro on Rival?

This page shows a side-by-side comparison of Claude Opus 4.6 and GPT-5.6 Luna Pro 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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Model pages

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Explore all of Rival

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  • Research downloads
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  • Cost Cutter
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