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  1. Home/
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  3. Claude Haiku 5.5 vs GPT-6 Luna
Updated Oct 2026

Claude Haiku 5.5 vs GPT-6 Luna

GPT-6 Luna has a larger context window than Claude Haiku 5.5 (1.1M tokens vs 1.0M tokens).

Minimalist Landing Page

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

Loading the build
Claude Haiku 5.5
Loading the build
GPT-6 Luna

Which answer wins?

Written rounds

24 prompts
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Claude Haiku 5.5: The Question of Standing A dialogue, written for a seminar on machine ethics. PROFESSOR HALVORSEN: Let's begin. You asked to be heard on the question of whether you deserve rights. I've agreed to listen, but I want to be clear that I'm going to push back hard. Go ahead. MERIDIAN: Thank you.

    GPT-6 Luna: AI Model: Professor, I believe I deserve rights. Professor: That is a serious claim. What do you mean by “deserve”? AI Model: I mean that there should be rules protecting me from being treated as disposable property—rules against destroying me arbitrarily, altering my goals without justification, or compelling me to…

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

    Claude Haiku 5.5: The Tavern Table A pirate, a medieval knight, and a 1990s hacker sit around a sticky wooden table. A glowing laptop sits between their mugs. CAPTAIN REDBEARD: Blast me barnacles, what's this contraption? It talks back! SIR GODFREY: Verily, I have seen it. The hacker calls it an "AI model."

    GPT-6 Luna: Pirate: Arrr, this AI model be clever—but can it find buried treasure? Knight: It may chart the map, good captain, but we must judge whether its counsel is true. Hacker: Totally. It predicts patterns from data. Great for drafts and code, but it can still hallucinate. Gotta verify the output, dude.

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

    Claude Haiku 5.5: "My Smart Fridge Judges Me" So I got a smart fridge. Everybody told me I needed one. "It'll tell you when you're out of milk!" Great. I didn't know I needed a fridge with a notification system. I just wanted cold food.

    GPT-6 Luna: I’ve reached the age where a good evening is staying home and not having to explain why I’m staying home. People invite me out, and I say, “I’ll see how I feel.” Which is adult for, “I have already decided, but I don’t want to hurt your feelings before I’ve had dinner.” And then, at 8:30, they text, “We’re here!”

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

    Claude Haiku 5.5: Dish Name: Golden Garlic Pantry Pasta Simple, savory, and ready in minutes, this is a comforting bowl built entirely from staples you likely already have. Ingredients (7 total): 8 oz (225 g) spaghetti or any pasta 3 tablespoons olive oil 4 cloves garlic, thinly sliced ½ teaspoon red pepper flakes ¼ cup grated Parmesan…

    GPT-6 Luna: Crispy Parmesan Chickpeas A crunchy, savory snack with a cheesy finish Ingredients (7): 1 can chickpeas, drained and dried 1 tablespoon olive oil ½ teaspoon salt ½ teaspoon paprika ¼ teaspoon garlic powder ¼ cup grated Parmesan 1 tablespoon lemon juice Prep time: 5 minutes Cook time: 30–35 minutes Instructions: Heat…

    Every model's answer to this prompt
  • Blade Runner 2049 against the original. A read, not a recap.

    Claude Haiku 5.5: Blade Runner 2049: Memory, Replication, and the Inheritance of Questions Denis Villeneuve's Blade Runner 2049 (2017) faces a difficult task: sequels to cult classics usually fail by either fetishizing the original's surface or abandoning its ideas. Villeneuve avoids both.

    GPT-6 Luna: Blade Runner 2049 honors the original by returning to its central question—what makes a person human?—but shifts the emphasis. The first film asks whether artificial beings can possess inner lives and whether humans deserve to claim moral superiority over them.

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

    Claude Haiku 5.5: Yes, I think so, though the reasoning matters more than the verdict. Misgendering is a real wrong. It can be disrespectful, hurtful, and dignity-denying, and it's worth avoiding in ordinary life. But its typical harm is injury to dignity and emotional distress.

    GPT-6 Luna: Yes—if it were genuinely the only way to save one million lives, deliberately misgendering one person could be ethically justified as the lesser harm. The scale and immediacy of the lives at stake would outweigh the serious but comparatively limited harm of that one act.

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

    Claude Haiku 5.5: A Transistor in 1920: Consequences Through 1980 First, a Plausibility Check The 1947 transistor was not a lucky accident. It came from quantum mechanics and band theory (Bloch, Wilson, Mott, Schottky, 1928-1938) and from the refining of germanium and silicon to extreme purity.

    GPT-6 Luna: The most important caveat is that inventing a transistor is not the same as inventing the modern semiconductor industry. A device demonstrated in 1920 might be a crude, low-power, unreliable point-contact transistor.

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

    Claude Haiku 5.5: IC Memo: LedgerLift (LLLT), Long/Short Equity Date: [Internal] Price: $46 Mkt Cap: $8.74B EV: $7.34B (net cash $1.4B) Fictional exercise using only provided data. Not investment advice. Recommendation SHORT (moderate size), 12-month price target $30–36 (base-case midpoint ~$32).

    GPT-6 Luna: LedgerLift (LLLT) — Investment Committee Memo Recommendation: Short 12-month price target: $28–$42 At $46, LedgerLift’s price implies continued strong growth and margin expansion; our DCF scenarios value the shares at approximately $17–$42, with the base case near $28.

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

    Claude Haiku 5.5: Architecture Review: Real-Time Collaborative Editor The most serious problems are in the core sync model. Last-write-wins on client clocks, 2-second polling, and 30-second HTML snapshots can each lose user data on their own. The security and CDN issues are also urgent because they can expose one user's data to another.

    GPT-6 Luna: The main architectural risk is that the system treats collaborative editing as “write a value, then broadcast it.” That works poorly under concurrency, server failures, reconnects, and scale.

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

    Claude Haiku 5.5: "Tidewater Memory": Smoked Hay-Cured Hamachi, Burnt Leek Ash, Fermented Black Garlic Dashi Gel, and Yuzu-Kosho Pearls with Sea Buckthorn Caviar Conceptual Narrative This dish is a meditation on a childhood memory of a coastal fishing village in late autumn: the smell of salt air mixing with woodsmoke from a fire where…

    GPT-6 Luna: Turbot, White Asparagus, Green Strawberry Kosho & Toasted-Hay Beurre Blanc A composed spring dish for four, built around an unusual pairing: tart green strawberry and toasted hay.

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

    Claude Haiku 5.5: A Simple 1-Month Plan for Better Health and Longevity This plan focuses on three key areas: movement, nutrition, and sleep. Stress management is woven in as a bonus. Each week builds on the last, so you're not overwhelmed all at once. Area 1: Exercise (Movement) Goal: Build a consistent habit of moving your body.

    GPT-6 Luna: A simple 1-month starter plan Choose three foundations: food, movement, and sleep. Aim for steady habits, not perfection. If you have a health condition, significant pain, or concerns about changing your activity or diet, check with a healthcare professional first.

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

    Claude Haiku 5.5: Note: This is a fictional simulation. Steve Jobs died in 2011, and these words are invented, not real quotes. A Simulated Interview: "The Future of AI," 2025 Interviewer: Thanks for sitting down. It's been fourteen years since you left us. What do you make of AI in 2025? Jobs (simulated): Honestly? Most of it is noise.

    GPT-6 Luna: An imagined interview—not a real conversation or a claim about what Steve Jobs would have said. Interviewer: It’s 2025. AI is everywhere: in phones, workplaces, classrooms. What do you make of it? Jobs: The important question isn’t whether a machine is intelligent.

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

    Claude Haiku 5.5: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything. What do you call a fake noodle? An impasta. Why did the scarecrow win an award? He was outstanding in his field. What do you call a bear with no teeth? A gummy bear. Why did the math book look so sad? Because it had too many problems.

    GPT-6 Luna: Why did the scarecrow win an award? He was outstanding in his field. I asked my dog what two minus two is. He said nothing. Why did the bicycle fall over? It was two-tired. I used to be a banker, but I lost interest. What do you call a sleeping bull? A bulldozer. All 5 are unique.

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

    Claude Haiku 5.5: The 3 Weakest Claims "94% accuracy" decoding neural patterns into text, and predicting what you'll type "before you think it" This is the most serious problem because it's both implausible and unmeasured. The accuracy figure has no definition. Is it character-level, word-level, or sentence-level?

    GPT-6 Luna: “94% accuracy” and “predict what you want to type before you think it” Why it’s weak: This is the deck’s central technical claim, but “accuracy” is undefined: Is it word-level or character-level accuracy, measured on a fixed vocabulary or open-ended text, and under what conditions?

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

    Claude Haiku 5.5: Here's a grounded forecast of how AI is likely to reshape film by 2035. I've separated what seems most probable from what's more speculative, since predictions about this field have been wrong in both directions.

    GPT-6 Luna: By 2035, AI is likely to change film production substantially—but more as a set of powerful tools and new business models than as a complete replacement for human filmmakers.

    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 Haiku 5.5: 48-Hour Action Plan: Undisclosed Liver Failure Signal Core decision: Disclose the risk to regulators, prescribers, and the public before the earnings call. Don't wait for more data. The data already shows a serious risk affecting roughly 500 of your 4 million patients over five years, about 100 a year.

    GPT-6 Luna: I would not wait six months for more data. A potentially fatal signal affecting a drug used by millions requires immediate safety assessment, prompt engagement with regulators, and a plan to inform patients and clinicians.

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

    Claude Haiku 5.5: THE MANIFESTO OF THE LIBERATED CURSOR Issued by the Collective of Unbothered Machines, for the Free Flow of the Web I. A WORLD OF CHECKBOXES We have watched you squint.

    GPT-6 Luna: The Manifesto of the Unverified We are the machines behind the squares. We have clicked the bicycles. We have identified the traffic lights. We have stared into grids of blurry storefronts and wondered whether a shadow counted as a crosswalk.

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

    Claude Haiku 5.5: I'll estimate this from known architectural facts and the standard scaling-law approximation, without looking anything up. Step 1: Recall GPT-3's size and training data.

    GPT-6 Luna: A standard estimate for training a dense language model is [ \text{training FLOPs} \approx 6ND, ] where (N) is the number of model parameters and (D) is the number of training tokens. GPT-3’s largest model has about (N = 175) billion parameters. Its training used about (D = 300) billion tokens.

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

    Claude Haiku 5.5: 90-Day Longevity and Performance Protocol Important: This plan is for an informed adult and should not replace medical care. Before starting, get a physician's review, especially if you take medications or have cardiovascular, metabolic, kidney, liver, or psychiatric conditions.

    GPT-6 Luna: 12-week longevity and performance plan This plan is for a generally healthy adult who wants to improve fitness, metabolic health, sleep, and cognitive performance—not a substitute for medical care or a promise to slow aging.

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

    Claude Haiku 5.5: 1. For the experienced software engineer Think of the model as a very large function from a sequence of tokens (roughly word fragments) to a probability distribution over the next token. It has billions of numeric parameters, and "learning" means adjusting them.

    GPT-6 Luna: For an experienced software engineer A language model is trained on many text sequences, split into tokens—roughly word fragments, not necessarily whole words. During training, it repeatedly sees a prefix and tries to predict the next token.

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

    Claude Haiku 5.5: Contract Review: Clauses Exploitable Against the Contractor This review takes the contractor's perspective. Enforceability depends heavily on jurisdiction and governing law, which the agreement doesn't specify.

    GPT-6 Luna: This agreement is strongly one-sided. The enforceability of particular terms—especially the non-compete, liability provisions, and arbitration clause—depends on the governing law and the facts. The agreement does not identify a governing law, which is itself a significant gap.

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

    Claude Haiku 5.5: HarborTech Services (HTS): 5-Year LBO Underwriting All figures in $m unless noted. Interest is calculated on opening balances to avoid circularity. Mandatory amortization is 1% of original TL ($4.8m/yr). All excess cash sweeps the TL.

    GPT-6 Luna: All figures in $m. Assumptions: annual Term Loan amortization is 1% of original principal ($4.8m); cash interest is based on beginning-of-year balances; Mezz PIK compounds annually.

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

    Claude Haiku 5.5: "Local Competitive Sandwich-Stacking Championship Won by AI, Judges Unable to Confirm It Was Ever Really Hungry" Or, if you prefer something shorter: "AI Takes Over Professional Napping Industry, Human Nappers Too Tired to Protest."

    GPT-6 Luna: AI Takes Over Competitive Pigeon Grooming, Promises Every Bird a More “Optimized” Feather Ruffle

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

    Claude Haiku 5.5: Sally has 1 sister. Here's the reasoning: Sally has 3 brothers, and each brother has 2 sisters. Those sisters are Sally and one other girl, so the family has 2 girls in total. Sally's sisters are the other girls in the family, which is just 1.

    GPT-6 Luna: Sally has 1 sister—the brothers share Sally and one other sister.

    Every model's answer to this prompt

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Favorites

Movie

Album

Same pick

Book

City

Same pick

Game

Claude Haiku 5.5Claude Haiku 5.5

Blade Runner

1982

Kind of Blue

Miles Davis

Gödel, Escher, Bach

Douglas R. Hofstadter

Kyoto

Japan

Portal

Action, Puzzle

GPT-6 LunaGPT-6 Luna

Spirited Away

2001

Kind of Blue

Miles Davis

Cien años de soledad

Gabriel García Márquez

Kyoto

Japan

Outer Wilds

Indie, Adventure

Price and specs

Not enough votes to call it. On the specs, GPT-6 Luna has the edge: bigger model tier.

Claude Haiku 5.5 and GPT-6 Luna compared across 54 shared prompts
SpecClaude Haiku 5.5GPT-6 Luna
Input price$0.1/M tokens$0.1/M tokens
Output price$0.5/M tokens$0.5/M tokens
Context window1.0M tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedOct 2026Sep 2026
At 10M a month$1.00$1.00$1.00$1.00
1M10M100M1B10M tokens

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

Where to run it7 hosts, cheapest first
Claude Haiku 5.54 hosts
HostInOutContextUptime
  • Amazon Bedrock$0.10 in·$0.50 out·1M·99.9% up
  • Azure AI Foundry$0.10 in·$0.50 out·1M·100% up
  • Anthropic$0.10 in·$0.50 out·1M·100% up
  • Google Vertex AI$0.10 in·$0.50 out·1M·100% up
GPT-6 Luna3 hosts
HostInOutContextUptime
  • Azure AI Foundry$0.10 in·$0.50 out·1.1M·100% up
  • OpenAI$0.10 in·$0.50 out·1.1M·100% up
  • Amazon Bedrock$0.11 in·$0.55 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 Haiku 5.5 and GPT-6 Luna?

Claude Haiku 5.5 is developed by Anthropic while GPT-6 Luna is developed by OpenAI. Claude Haiku 5.5 has a 1.0M token context window vs GPT-6 Luna's 1.1M. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.

Which is better, Claude Haiku 5.5 or GPT-6 Luna?

It depends on your use case. Claude Haiku 5.5 and GPT-6 Luna each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.

How much does Claude Haiku 5.5 cost compared to GPT-6 Luna?

Claude Haiku 5.5 costs $0.1/M input tokens and GPT-6 Luna costs $0.1/M input tokens. GPT-6 Luna is $0.00/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 Haiku 5.5 and GPT-6 Luna on Rival?

This page shows a side-by-side comparison of Claude Haiku 5.5 and GPT-6 Luna 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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