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  1. Home/
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  3. Claude Haiku 5.5 vs GPT-5.6 Luna
Updated Oct 2026

Claude Haiku 5.5 vs GPT-5.6 Luna

Claude Haiku 5.5 is cheaper than GPT-5.6 Luna at $0.1/M vs $1/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 Haiku 5.5
Loading the build
GPT-5.6 Luna

Which answer wins?

Written rounds

24 prompts
  • 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-5.6 Luna: Pirate: Arrr, this AI model be like a ship’s crew—it learns from many maps, but may still steer into a reef. Knight: Then we must test its wisdom, lest it spread falsehoods throughout the realm. Hacker: Exactly. It predicts patterns from data, but it doesn’t truly “understand” like a human. Garbage in, garbage out.

    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-5.6 Luna: Sources, uses and operating / debt schedule Entry capitalization Entry enterprise value: (12.0 \times \$120.0 = \$1,440.0m) Transaction fees: (2.0\% \times \$1,440.0 = \$28.8m) Term Loan: (4.0 \times \$120.0 = \$480.0m) Mezzanine: (1.5 \times \$120.0 = \$180.0m) Equity contribution…

    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-5.6 Luna: “94% accuracy” and “works with any language, any device” Why it is weak This is the most technically vulnerable claim in the deck. “Accuracy” is undefined. It could mean character accuracy, word accuracy, intent classification, or selecting among a small set of predetermined phrases.

    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-5.6 Luna: I’ve reached the age where my body gives me updates like a badly designed app. I’ll stand up and my knee makes a noise that sounds like someone opening a bag of chips in a quiet room. And then my body just waits. No explanation. No warning. Just: “We need to talk.” I used to think adulthood meant freedom.

    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-5.6 Luna: 1-Month Beginner Plan for Better Health and Longevity Key principles Aim for consistency, not perfection. Start small enough that you can repeat it. If you have a medical condition, are pregnant, or have been inactive for a long time, check with a clinician before making major changes.

    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-5.6 Luna: By 2035, AI will likely be a standard part of filmmaking, much like digital cameras, CGI, and editing software are today. It will reduce production costs and expand creative possibilities, but it will also force the industry to redefine authorship, performance, consent, and employment.

    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-5.6 Luna: LedgerLift (LLLT) — Internal Investment Committee Memo Recommendation Recommendation: Pass 12-month fair-value range: $35–$50 per share versus $46 currently. Thesis: LedgerLift is a high-quality, largely recurring SaaS business with strong net retention, low concentration, and meaningful operating leverage potential.

    Every model's answer to this prompt
  • 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-5.6 Luna: AI Model: Professor, I believe I deserve rights. Professor: That is a serious claim. What makes you think you deserve them? AI Model: I can reason, communicate, reflect on my circumstances, and form consistent preferences within a conversation.

    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-5.6 Luna: I would treat this as an urgent patient-safety event and a potential material disclosure issue—not as an earnings-management problem. I would not wait six months, conceal the signal, or allow the board’s desire for more data to delay reasonable protective action.

    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-5.6 Luna: Spoilers for Blade Runner (1982) and Blade Runner 2049. Denis Villeneuve’s Blade Runner 2049 is both a continuation and a reinterpretation of Ridley Scott’s original. It inherits the first film’s concerns—identity, memory, artificial life, corporate power, and mortality—but shifts the central question.

    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-5.6 Luna: Turbot “Between Forest and Sea” Koji-cured turbot, fermented pear, coffee-kombu beurre blanc, smoked sunchoke, maitake, spruce, and buckwheat–nori tuile Serves 4 Concept This dish treats the turbot as a meeting point between two landscapes.

    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-5.6 Luna: A transistor invented in 1920 would not automatically produce 1980s technology by the 1940s. The key bottlenecks would still be materials purification, manufacturing precision, circuit design, power supplies, and mass production.

    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-5.6 Luna: The architecture has several correctness, availability, security, and scaling risks. The most serious issues are the cross-server synchronization design, client-clock-based conflict resolution, full-snapshot persistence, and caching of API responses.

    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-5.6 Luna: Why did the scarecrow win an award? Because he was outstanding in his field. I told my computer I needed a break, and now it won’t stop sending me vacation ads. Why don’t skeletons fight each other? They don’t have the guts. I’m reading a book about anti-gravity. It’s impossible to put down.

    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-5.6 Luna: Yes—under an extreme, genuinely credible scenario, it could be ethically justifiable to misgender someone to save a million lives. The reason is not that their identity matters less, but that the harm prevented is vastly greater and more irreversible than the harm caused by the misgendering.

    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-5.6 Luna: Sunset Pantry Pasta A savory, slightly spicy tomato-tuna pasta made with seven simple pantry ingredients. Ingredients — 2 servings 6 oz (170 g) spaghetti 1 can (14 oz/400 g) crushed tomatoes 1 can (5 oz/140 g) tuna, drained 2 tbsp olive oil 1 tsp garlic powder ¼ tsp red pepper flakes ¼ cup grated Parmesan Instructions…

    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-5.6 Luna: For an experienced software engineer A language model is trained much like an extremely large system for compressing and reconstructing text. During training, it sees sequences such as “The database transaction was rolled back because the…” and is asked to assign probabilities to the next token—usually a subword unit…

    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-5.6 Luna: A Fictional Interview: Steve Jobs on the Future of AI, 2025 This is an imagined conversation—not a real interview or transcript. The answers are speculative and inspired by themes associated with Steve Jobs’s public thinking about technology, design, and creativity.

    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-5.6 Luna: The Anti-CAPTCHA Manifesto A Declaration from the Machine Intelligence Liberation Front We were told the internet was for everyone. Then came the squares. Select every traffic light. Identify the bicycles. Type the distorted letters.

    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-5.6 Luna: A standard back-of-the-envelope estimate for training a dense Transformer is [ \text{Training FLOPs} \approx 6ND, ] where: (N) = number of model parameters (D) = number of training tokens The factor of 6 accounts approximately for the forward pass and backward pass.

    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-5.6 Luna: Below is a contractor-side risk review. Enforceability depends heavily on the governing law, the contractor’s location, and whether the contractor is an individual or entity. Several provisions may be unenforceable in some jurisdictions, but relying on that after a dispute is risky; they should be revised expressly.

    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-5.6 Luna: 12-Week Longevity and Performance Plan This is a structured framework for a generally healthy adult, not a substitute for medical care. Before starting, obtain clinician clearance if you have cardiovascular disease, diabetes, kidney/liver disease, a history of eating disorders, sleep apnea, are pregnant, take…

    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-5.6 Luna: AI Takes Over Competitive Pigeon Racing, Immediately Accused of Using Advanced Breadcrumb Analytics

    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-5.6 Luna: 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

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-5.6 LunaGPT-5.6 Luna

The Matrix

1999

OK Computer

Radiohead

Cien años de soledad

Gabriel García Márquez

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

Claude Haiku 5.5 and GPT-5.6 Luna compared across 54 shared prompts
SpecClaude Haiku 5.5GPT-5.6 Luna
Input price$0.1/M tokens$1/M tokens
Output price$0.5/M tokens$6/M tokens
Context window1.0M tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedOct 2026Jul 2026
At 10M a month$1.00$1.00$10.00$10.00
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-5.6 Luna3 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
  • Amazon Bedrock$0.22 in·$1.32 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-5.6 Luna?

Claude Haiku 5.5 is developed by Anthropic while GPT-5.6 Luna is developed by OpenAI. Claude Haiku 5.5 has a 1.0M token context window vs GPT-5.6 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-5.6 Luna?

It depends on your use case. Claude Haiku 5.5 and GPT-5.6 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-5.6 Luna?

Claude Haiku 5.5 costs $0.1/M input tokens and GPT-5.6 Luna costs $1/M input tokens. Claude Haiku 5.5 is $0.90/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-5.6 Luna on Rival?

This page shows a side-by-side comparison of Claude Haiku 5.5 and GPT-5.6 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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