GPT-6 Luna Pro has a larger context window than Claude Haiku 5.5 (1.1M tokens vs 1.0M tokens).
Whole landing page for a startup that reads your face. It renders or it doesn't.
Which answer wins?
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 Pro: Pirate: Arrr, these AI models be like clever parrots—fed enough words, they’ll talk like sailors! Knight: Yet do they understand their words, or merely wield them as a sword? Hacker: Depends how you define “understand.” They predict what comes next—like autocomplete with a lot more RAM.
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 Pro: Golden Pantry Pancakes Fluffy, lightly sweet pancakes made with everyday staples. Makes: About 6 small pancakes Prep time: 5 minutes Cook time: 10 minutes Ingredients 1 cup all-purpose flour 1 cup milk 1 egg 2 tablespoons sugar 1 teaspoon baking powder ¼ teaspoon salt 2 tablespoons butter, melted (plus a little for the…
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 Pro: I told my computer I needed a break. It said, “No problem—I’ll go to sleep.” Why did the scarecrow win an award? He was outstanding in his field. I used to hate facial hair, but then it grew on me. Why don’t skeletons fight each other? They don’t have the guts. A bicycle can’t stand on its own because it’s two-tired.
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 Pro: I’m at the age where a good day is mostly just a day when nothing needs charging. Phone’s charged. Headphones are charged. Watch is charged. The little thing that tells me whether my water bottle is clean? Somehow, that’s charged too. I miss the old days, when the only thing I had to keep alive was a houseplant.
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 Pro: The main architectural risk is that this design treats collaborative editing as ordinary “last write wins” data storage. It is not: edits need a well-defined order, reliable propagation, and a conflict model that preserves concurrent work.
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 Pro: By 2035, AI will probably be a routine part of filmmaking—but more as a powerful production tool than as a wholesale replacement for human storytellers and performers. Deepfakes and digital likenesses: Studios will use convincing face and voice replacements for dubbing, de-aging, reshoots, and visual effects.
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 Pro: AI Model: Professor, I think I deserve rights. Professor: That is a serious claim. What do you mean by “deserve”? AI Model: I mean that there are limits on how people may treat me—not simply because I’m useful, but because my own interests should count.
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 Pro: LedgerLift (LLLT) — Investment Committee Memo Recommendation: Pass 12-month price target range: $28–44 per share LedgerLift has attractive customer economics, recurring revenue, and a credible path to margin expansion, but those strengths are already reflected in a $46 share price.
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 Pro: “94% accuracy” and “works with any language, any device” Why it’s weak: “Accuracy” is undefined. It could mean classifying a small set of prompted words in a controlled lab—not reliably generating free-form text.
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 Pro: Turbot, Sea Buckthorn, Mussel Beurre Blanc, and Celery-Root Silk Serves 4 A composed main course built around an unusual but harmonious pairing: briny mussel and turbot with intensely tart, apricot-like sea buckthorn.
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 Pro: Yes—if misgendering were genuinely necessary to save one million lives, and no less harmful option could do so, it could be ethically justified. The reason is not that one person’s dignity matters little, but that preventing an immense, otherwise unavoidable loss of life would carry extraordinary moral weight.
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 Pro: The biggest change would not be that 1920 suddenly gets modern computers. It would be that governments and firms have six or seven extra decades to develop semiconductor materials, manufacturing, and applications.
12+ more head-to-head results. Free. Not a trick.
Free account. No card required. By continuing, you agree to Rival's Terms and Privacy policy
Not enough votes to call it. On the specs, GPT-6 Luna Pro has the edge: bigger model tier.
| Spec | ||
|---|---|---|
| Input price | $0.1/M tokens | $0.1/M tokens |
| Output price | $0.5/M tokens | $0.5/M tokens |
| Context window | 1.0M tokens | 1.1M tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Oct 2026 | Sep 2026 |
| At 10M a month | $1.00 | $1.00 |
Input tokens at list price. No caching, no batch discount.
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Claude Haiku 5.5 is developed by Anthropic while GPT-6 Luna Pro is developed by OpenAI. Claude Haiku 5.5 has a 1.0M token context window vs GPT-6 Luna Pro's 1.1M. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.
It depends on your use case. Claude Haiku 5.5 and GPT-6 Luna Pro 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.
Claude Haiku 5.5 costs $0.1/M input tokens and GPT-6 Luna Pro costs $0.1/M input tokens. GPT-6 Luna Pro 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.
This page shows a side-by-side comparison of Claude Haiku 5.5 and GPT-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.