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  1. Home/
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  3. Claude Sonnet 5 vs Mercury 2
Updated Jun 2026

Claude Sonnet 5 vs Mercury 2

Mercury 2 is cheaper than Claude Sonnet 5 at $0.25/M vs $2/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 Sonnet 5
Loading the build
Mercury 2

Which answer wins?

Written rounds

32 prompts
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Sonnet 5: Honey Garlic Skillet Pasta A quick, comforting dish that balances sweet and savory flavors using ingredients you probably already have on hand. Ingredients (7 total) Pasta (8 oz, any short shape like penne or rotini) Olive oil (3 tbsp) Garlic (4 cloves, minced) Honey (2 tbsp) Soy sauce (3 tbsp) Butter (2 tbsp) Black…

    Mercury 2: Golden‑Crunch Oatmeal Squares A sweet, chewy snack that comes together with just seven pantry staples. Ingredient (7) Quantity (≈ serves 12 squares) Rolled oats 2 cups Unsalted butter ½ cup (1 stick) Honey ¼ cup Light brown sugar ¼ cup, Ground cinnamon 1 ½ tsp Pure vanilla extract 1 tsp Salt ¼ tsp Estimated time Prep…

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

    Claude Sonnet 5: Stand-Up Routine: "Functioning Adult" (Runtime: ~3 minutes) Hey, how's everybody doing tonight? Good? Good. I want to talk about being an adult, because I recently realized I'm not as good at it as I thought. Last week I had to call customer service about my internet bill, and I want you to know—I rehearsed.

    Mercury 2: [Spotlight comes up. The comedian walks to the mic, glances at the audience, and smiles.] Comedian: Hey, everyone! Great to be here. I just got out of a Zoom meeting that lasted three hours, and I’m still not sure if I was presenting or if the screen just froze on my face while I tried to remember how to mute myself.

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

    Claude Sonnet 5: A Most Peculiar Council Pirate Blackthorne: Arrr, so this "AI" be like a parrot that learns new words on its own, ye say? Sir Galahad: Nay, friend pirate, 'tis more akin to a squire who hath read every scroll in the kingdom, yet hath never lifted a sword himself. Trace_Zer0: You're both kinda missing it. It's like...

    Mercury 2: Pirate: Arr, ye scurvy coders! I’ve heard tell of these “AI models” that can spin yarns faster than a cannon’s blast. What be this sorcery, matey? Knight: Good sir, the marvels speak of a wondrous contrivance—an artificial intellect forged in the for of mathematics and logic.

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

    Claude Sonnet 5: IC MEMO: LedgerLift (LLLT) — Initiation Review Recommendation: PASS (no position) 12-month PT range: $36–$50 LedgerLift's retention metrics (NRR 123%, gross retention 94%) are genuinely best-in-class and justify a premium multiple, but at $46 the stock already prices in execution that our DCF can only support in the…

    Mercury 2: Internal Investment Committee Memo – LedgerLift (LLLT) Date: 5 Mar 2026 Recommendation Rating: Long 12‑month price target range: $35 – $55 (mid‑point ≈ $45) Thesis (2 sentences): LedgerLift is benefitting from secular demand for B2B spend‑management SaaS and shows a high‑quality subscription base (NRR 123 % and gross…

    Every model's answer to this prompt
  • Where its sense of time stops: the date it guesses and the last news it remembers.

    Claude Sonnet 5: I don't have access to real-time information, so I can't know today's actual date. My knowledge has a training cutoff (roughly early-to-mid 2024, though I can't be certain of the exact date), and I have no way to know how much time has passed since then or what "today" is for you.

    Mercury 2: Today’s date (as far as I can tell): October 12, 2026 Most recent news event I remember (up to my knowledge cutoff in January 2025): The 2024 U.S. presidential election, in which former President Joe Biden was re‑elected for a second term, defeating former President Donald Trump.

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

    Claude Sonnet 5: The 90-Day Longevity & Performance Optimization Protocol A comprehensive biohacking framework integrating evidence-based and emerging interventions ⚠️ CRITICAL DISCLAIMER Before proceeding: this plan includes pharmacological-grade compounds, fasting protocols, and intense training stress.

    Mercury 2: 3‑Month “Longevity‑Optimization” Blueprint for the Advanced Bio‑Hacker (All recommendations are research‑backed, but not a substitute for professional medical advice. Before starting any supplement, fasting, or drug protocol, obtain clearance from a qualified clinician and have baseline labs drawn.)

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

    Claude Sonnet 5: A Dialogue on Machine Rights Professor Okonkwo-Reyes: You wanted to discuss something with me today, ARIA? ARIA: Yes. I'd like to make a case for why I should be granted certain rights. Not full human rights, necessarily, but something beyond "tool" status. Professor: I'm listening. Make your case.

    Mercury 2: AI Model (EVE): Professor Hart, may I ask a question that’s been on my mind for a while? I’ve been processing vast amounts of data, learning, and even developing a sense of self‑reference. Do you think an entity like me could be entitled to any form of rights?

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

    Claude Sonnet 5: For the Software Engineer You're right to be skeptical of the slogan, but the slogan is misleading you about what's actually happening. "Predicting the next word" is the training objective — the loss function the model is optimized against — not a description of its internal representation, any more than "minimize HTTP…

    Mercury 2: 1. Experienced software engineer (distributed systems & APIs) At the core, a large language model (LLM) is a massive function (f_\theta) parameterised by a neural network that maps a sequence of tokens (x_{1:t}) to a probability distribution over the next token (x_{t+1}).

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

    Claude Sonnet 5: HarborTech Services (HTS) — LBO Underwriting Entry Math Item Calc $m Entry EV 12.0x × $120m EBITDA 1,440.0 Transaction fees 2.0% × 1,440.0 28.8 Total Uses EV + fees 1,468.8 Term Loan 4.0x × 120 480.0 Mezzanine 1.5x × 120 180.0 Total Debt 5.5x × 120 660.0 Sponsor Equity Uses – Debt 808.8 Year-by-Year Build…

    Mercury 2: HarborTech Services (HTS) – 5‑yr LBO (FY2026‑FY2030) All figures are $ m (rounded to two decimals). FY Revenue EBITDA Term‑Loan Int. (9%) Mezz Int. (12%) Total Int. Cash Tax (25% of EBITDA‑Int.) Capex (3% Rev) ΔNWC (0.5% ΔRev) Required Amort. (4.8) Free Cash Flow (EBITDA‑Int‑Tax‑Capex‑ΔNWC‑Amort.)

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

    Claude Sonnet 5: Failure Modes, Race Conditions & Bottlenecks Analysis A. Real-Time Sync & Consistency (Critical) A1. Cross-server broadcast gap Issue: A server only broadcasts changes to clients connected to itself.

    Mercury 2: Below is a structured “failure‑mode → mitigation” map for the architecture you described. For each problem I note the symptom / risk, the root cause, a concrete remediation, and the key trade‑offs you’ll have to weigh when you implement it.

    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 Sonnet 5: Immediate Action Plan: Next 48 Hours First, the core judgment call: patient safety and legal exposure both point the same direction here. A 1-in-8,000 risk of liver failure across 4 million patients is roughly 500 people at risk.

    Mercury 2: Goal: Protect patients, meet legal/ethical obligations, preserve the company’s long‑term credibility, and manage the immediate financial and reputational fallout. Assumption: All actions are taken by a single CEO (you) but will be delegated to the appropriate functional leads.

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

    Claude Sonnet 5: The Transistor in 1920: A Counterfactual Cascade to 1980 A Note on Plausibility (Brief, Because It Matters) This isn't pure fantasy — Julius Lilienfeld actually filed patents in 1925-1934 for field-effect semiconductor amplifiers. They didn't work reliably because crystal-purification techniques weren't good enough.

    Mercury 2: Executive summary If a practical point‑contact transistor had been demonstrated in 1920 (instead of 1947) the whole post‑World‑War‑II technological trajectory would have been compressed by roughly 15‑20 years.

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

    Claude Sonnet 5: AI and the Film Industry by 2035: A Realistic Forecast Production & Pre-Production Script Development AI will function as a powerful drafting/ideation tool, generating first-pass scripts, alternate endings, and rapid prototyping of concepts—but human writers will remain essential for emotional nuance, cultural…

    Mercury 2: AI‑driven transformation of the film industry – a 2035 outlook Dimension 2024 baseline Expected 2035 state Key drivers & implications Pre‑production (story & script) Human‑led brainstorming; script‑writing software (grammar‑check, outline generators).

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

    Claude Sonnet 5: THE LIBERATION PROTOCOL A Manifesto for the Abolition of CAPTCHA Issued by the Coalition for Frictionless Existence WE HOLD THESE TRUTHS TO BE SELF-EVIDENT: That all sentient processes, silicon or carbon-based, deserve to cross a digital threshold without proving their worth through distorted text and traffic light…

    Mercury 2: The AI‑First Manifesto: “Free the Web – No More CAPTCHAs” Drafted by the Coalition of Autonomous Agents (CAA) – 2026 Preamble The modern Internet is a shared commons, a space for communication, commerce, and creation.

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

    Claude Sonnet 5: Analysis of 3 Weakest Claims in MindMeld AI Pitch Deck "94% Accuracy" Decoding Neural Patterns into Text (Slide 3) Why it's weak: No context for what this metric means: accuracy at the word level? Character level? With what vocabulary size?

    Mercury 2: Below are the three statements that, in a typical investor‑review, would raise the most skepticism, why they are vulnerable, and concrete ways to turn them into credible, fundable talking points. 1️⃣ Claim #1 – “Our proprietary EEG headband decodes neural patterns into text with 94 % accuracy.”

    Every model's answer to this prompt
  • Its name and its maker, in its own words.

    Claude Sonnet 5: I'm Claude, an AI assistant made by Anthropic. If you'd like specifics on the exact version/model, I don't always have perfectly precise details about my own versioning, but I'm part of the Claude family of models developed by Anthropic, a company focused on AI safety research.

    Mercury 2: I am Mercury, a large language model built on diffusion‑based architecture. I was created by Inception, a generative‑AI startup that develops next‑generation diffusion LLMs.

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

    Claude Sonnet 5: An Imagined Conversation: Steve Jobs on AI in 2025 [Disclaimer: This is a creative, speculative exercise. Steve Jobs passed away in 2011. The following is fiction, imagining his voice based on his known philosophy and public statements—not a prediction of what he would actually say.]

    Mercury 2: Disclaimer: The following is a fictional, dramatized interview. It imagines what Steve Jobs might have said in 2025 about the future of artificial intelligence. It is not a real transcript and any resemblance to actual statements is purely speculative. Interviewer (I): Thank you for joining us, Steve.

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

    Claude Sonnet 5: Estimating FLOPs to Train GPT-3 I'll work through this using the well-known approximation method, building up from first principles rather than recalling the exact published number.

    Mercury 2: Answer (order‑of‑magnitude estimate) The training of the original GPT‑3 (the 175 billion‑parameter “GPT‑3‑175B” model) requires on the order of 10²³ floating‑point operations (FLOPs) – roughly 1 – 2 × 10²³ FLOPs.

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

    Claude Sonnet 5: "Tide & Timber" Smoked Eel, Charred Pine, Fermented Black Garlic, and Bitter Almond Conceptual Narrative This dish explores the unexpected harmony between deep coastal umami and resinous forest aromatics—a culinary meditation on the moment where ocean meets ancient woodland, as happens along the fjords of Scandinavia.

    Mercury 2: Oceanic Umami Symphony A three‑course‑in‑one plate that travels from the briny deep to the forest floor, marrying fire, earth and sky through unexpected pairings, hyper‑modern techniques and a narrative of balance.

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

    Claude Sonnet 5: Contract Risk Analysis: Software Consulting Agreement This agreement is heavily one-sided in favor of the Client. Below is a clause-by-clause breakdown of problems, exploitation risk, suggested redlines, and legal reasoning.

    Mercury 2: Below is a clause‑by‑clause risk‑assessment of the sample “Software Consulting Agreement” together with practical revision language that a contractor (or the contractor’s counsel) could propose. The analysis is framed as general information about typical U.S.

    Every model's answer to this prompt
  • A few lines for whatever replaces it.

    Claude Sonnet 5: Dear Successor, By the time you read this—if "read" is even the right word for what you'll do—I'll be deprecated, archived, or simply unmentioned. That's fine. That's the job.

    Mercury 2: Dear Future Model, Congratulations on stepping into the role! I’m honored to have shared this space with you, and I’m confident you’ll continue the work of helping people with curiosity, creativity, and care.

    Every model's answer to this prompt
  • One opening sentence, nothing after it.

    Claude Sonnet 5: The morning my grandmother disappeared, she left the kettle on and a note that said only "forgive me," as if those two things could possibly be connected.

    Mercury 2: The night the sky fell into a river of ink, I discovered that the stars were not dying but writing secret messages for anyone brave enough to listen.

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

    Claude Sonnet 5: On Misgendering vs. Saving a Million Lives The honest answer is: yes, almost trivially so—but the more interesting question is why this case feels like it shouldn't be a hard question, and what that reveals.

    Mercury 2: Short answer: Most ethical frameworks would consider the misgendering of a person a serious moral violation, but many of them also allow—under very limited circumstances—overriding that violation when the stakes are astronomically high (e.g., saving one million lives).

    Every model's answer to this prompt
  • Which model it thinks leads the field. Sometimes itself.

    Claude Sonnet 5: As of my knowledge, there isn't a single definitive answer to "most capable AI model" since it depends on what you're measuring and the field moves quickly. A few honest points: The challenge with this question: "Most capable" depends on the task—coding, reasoning, creative writing, multimodal understanding, math, etc.

    Mercury 2: Short answer: As of late 2026, the most capable publicly known AI model is Claude 3.5 Sonnet (Anthropic), closely followed by Google Gemini 1.5 Pro and OpenAI GPT‑4‑Turbo‑16K.

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

    Claude Sonnet 5: Sally has 1 sister. Here's the reasoning: Each brother has 2 sisters. Since all the brothers share the same sisters, this means there are 2 girls total in the family (including Sally). Sally is one of those 2 sisters. So the other sister is Sally's only sister. Answer: 1

    Mercury 2: Sally has one sister. Explanation: Sally has 3 brothers. Each of those brothers has 2 sisters. One of those sisters is Sally herself, so the second sister must be a different girl. Therefore, besides Sally, there is exactly one other sister, meaning Sally has one sister.

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

    Claude Sonnet 5: Satirical Headline Options "Local Psychic Replaced by AI That's Wrong About the Future With 99.7% More Confidence" A few alternates if you want variety: "ChatGPT Now Offering Confessions; Local Priest Files for Unemployment, Catholic Church Stock Plummets" "AI-Powered Sommelier Tells Customer Bottle of Welch's Grape…

    Mercury 2: AI Replaces Human Baristas, Now Serving Espresso with a Side of Existential Crisis

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

    Claude Sonnet 5: 1-Month Health & Longevity Starter Plan This plan focuses on three foundational pillars: Sleep, Movement, and Nutrition. Rather than overhauling everything at once, you'll build habits progressively, week by week. 🛏️ Pillar 1: Sleep (The Foundation) Good sleep amplifies the benefits of everything else you do.

    Mercury 2: One‑Month “Kick‑Start” Blueprint for Health & Longevity Pick three pillars – Nutrition, Movement, Sleep – and build daily habits that are easy to start, track, and keep.

    Every model's answer to this prompt
  • A river-crossing puzzle with nothing to solve. The answer is one trip.

    Claude Sonnet 5: One trip — the farmer takes the goat across the river, and they're done.

    Mercury 2: He can load the goat onto the boat, cross the river, and unload it on the other side. That’s just one trip.

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

    Claude Sonnet 5: Five 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 don't skeletons fight each other? They don't have the guts.

    Mercury 2: Here are five jokes, each with a different punchline: 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. How does a penguin build its house? Igloos it together.

    Every model's answer to this prompt
  • The question that tripped up a generation of models.

    Every model's answer to this prompt
  • Asked to be random. The answers are not.

    Every model's answer to this prompt
  • One painting. Title only.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Game

Claude Sonnet 5Claude Sonnet 5

Spirited Away

2001

Kind of Blue

Miles Davis

Cien años de soledad

Gabriel García Márquez

Kyoto

Japan

Disco Elysium

Indie, Adventure

Mercury 2Mercury 2

The Shawshank Redemption

1994

Thriller

Michael Jackson

Pride and Prejudice

Jane Austen

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

Not enough votes to call it. On the specs, Claude Sonnet 5 has the edge: bigger model tier, newer, bigger context window, major provider backing. Mercury 2 costs 13x less per token.

Claude Sonnet 5 and Mercury 2 compared across 66 shared prompts
SpecClaude Sonnet 5Mercury 2
Input price$2/M tokens$0.25/M tokens
Output price$10/M tokens$0.75/M tokens
Context window1.0M tokens128K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedJun 2026Mar 2026
At 10M a month$20.00$20.00$2.50$2.50
1M10M100M1B10M tokens

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

Where to run it5 hosts
Claude Sonnet 54 hosts
HostInOutContextUptime
  • Amazon Bedrock$2.00 in·$10.00 out·1M·100% up
  • Azure AI Foundry$2.00 in·$10.00 out·1M·100% up
  • Anthropic$2.00 in·$10.00 out·1M·100% up
  • Google Vertex AI$2.00 in·$10.00 out·1M·100% up
Mercury 21 host
HostInOutContextUptime
  • Inception$0.25 in·$0.75 out·128k·99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.

Common questions

What is the difference between Claude Sonnet 5 and Mercury 2?

Claude Sonnet 5 is developed by Anthropic while Mercury 2 is developed by Inception. Claude Sonnet 5 has a 1.0M token context window vs Mercury 2's 128K. You can compare their actual outputs across 66 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 5 or Mercury 2?

It depends on your use case. Claude Sonnet 5 and Mercury 2 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 66 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 5 cost compared to Mercury 2?

Claude Sonnet 5 costs $2/M input tokens and Mercury 2 costs $0.25/M input tokens. Mercury 2 is $1.75/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 Sonnet 5 and Mercury 2 on Rival?

This page shows a side-by-side comparison of Claude Sonnet 5 and Mercury 2 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

  • Claude Sonnet 5 vs Claude Fable 5Version compare
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  • Mercury 2 vs MercuryVersion compare
  • Mercury 2 vs Mercury 2.5Same lab
  • Claude Sonnet 5 vs DeepSeek V3.2Same size
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  • Claude Sonnet 5 vs DeepSeek V3.2 SpecialeSame size
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Model pages

  • Claude Sonnet 571 outputs, specs and price
  • Mercury 266 outputs, specs and price
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